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  • 51.
    Carlhäll, Carljohan
    et al.
    Linköping University, Department of Medicine and Care, Clinical Physiology. Linköping University, Faculty of Health Sciences.
    Hatle, L.
    Department of Cardiology, University Hospital Gasthuisberg, Leuven, Belgium.
    Nylander, Eva
    Linköping University, Department of Medicine and Care, Clinical Physiology. Linköping University, Faculty of Health Sciences.
    A novel method to assess systolic ventricular function using atrioventricular plane displacement: a study in young healthy males and patients with heart disease2004In: Clinical Physiology and Functional Imaging, ISSN 1475-0961, E-ISSN 1475-097X, Vol. 24, no 4, p. 190-195Article in journal (Refereed)
    Abstract [en]

    Analysis of atrioventricular plane displacement (AVPD) is a well established method for assessment of both systolic and diastolic ventricular function. For several years, AVPD has been a clinical tool and there are many current, as well as potential, areas of application. However, clinical work has shown that the traditional method for evaluation of systolic ventricular function, called total AVPD, does not temporally reflect true systole. Systolic AVPD is a new approach for measuring AVPD to assess ventricular systolic function. We wished to apply this new model in healthy subjects and in patients with different common heart diseases. Twenty-eight young healthy males and 30 patients (aortic stenosis, left sided regurgitant lesions, postmyocardial infarction) were enrolled. AVPD was obtained at the four standard sites by M-mode. Total AVPD was measured in the conventional way and systolic AVPD by identifying true systole, by means of mitral- and aortic valve closure respectively. Ventricular volumes were calculated according to biplane Simpson's rule. The systolic AVPD measurements were significantly lower than the total measurements, at both atrioventricular planes in all groups (P<0·001). This discrepancy was greater at the mitral than at the tricuspid annulus in the patients 24·2% vs. 15·5% (P<0·001), but did not differ in the healthy subjects. At the mitral annulus, this discrepancy also seemed to be more pronounced in the patients than in the healthy subjects 24·2% vs. 10·7%. When assessing ventricular systolic function by AVPD, the conventional method overestimates the amplitude in relation to true systolic function in both patients with heart disease and in young healthy males. Thus, there are uncertainties regarding earlier estimations of AVPD in terms of expression of systolic function and regarding previously presented reference values. We recommend the proposed methodology.

  • 52.
    Carlhäll, Carljohan
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Physiology. Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Kindberg, Katarina
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Modelling and Simulation .
    Karlsson, Matts
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Modelling and Simulation .
    Daughters, GT
    Miller, DC
    Ingels, NB
    Regional contribution of mitral annular dynamics to LV filling2006In: Experimental Biology,2006, 2006, p. A1194-A1194Conference paper (Other academic)
  • 53.
    Carlhäll, Carljohan
    et al.
    Linköping University, Department of Medicine and Care, Clinical Physiology. Linköping University, Faculty of Health Sciences.
    Kindberg, Katarina
    Linköping University, Department of Biomedical Engineering. Linköping University, The Institute of Technology.
    Wigström, Lars
    Linköping University, Department of Medicine and Care, Clinical Physiology. Linköping University, Faculty of Health Sciences.
    Daughters, G. T.
    Linköping University, Faculty of Health Sciences.
    Millers, D. C.
    Linköping University, Faculty of Health Sciences.
    Karlsson, Matts
    Linköping University, Department of Biomedical Engineering. Linköping University, The Institute of Technology.
    Ingels Jr, N. B.
    Linköping University, Faculty of Health Sciences.
    Contribution of mitral annular dynamics to LV diastolic filling with alteration in preload and inotropic state2007In: American Journal of Physiology. Heart and Circulatory Physiology, ISSN 0363-6135, E-ISSN 1522-1539, Vol. 293, no 3, p. G1473-H1479Article in journal (Refereed)
    Abstract [en]

    Mitral annular (MA) excursion during diastole encompasses a volume that is part of total left ventricular (LV) filling volume (LVFV). Altered excursion or area variation of the MA due to changes in preload or inotropic state could affect LV filling. We hypothesized that changes in LV preload and inotropic state would not alter the contribution of MA dynamics to LVFV. Six sheep underwent marker implantation in the LV wall and around the MA. After 7–10 days, biplane fluoroscopy was used to obtain three-dimensional marker dynamics from sedated, closed-chest animals during control conditions, inotropic augmentation with calcium (Ca), preload reduction with nitroprusside (N), and vena caval occlusion (VCO). The contribution of MA dynamics to total LVFV was assessed using volume estimates based on multiple tetrahedra defined by the three-dimensional marker positions. Neither the absolute nor the relative contribution of MA dynamics to LVFV changed with Ca or N, although MA area decreased (Ca, P < 0.01; and N, P < 0.05) and excursion increased (Ca, P < 0.01). During VCO, the absolute contribution of MA dynamics to LVFV decreased (P < 0.001), based on a reduction in both area (P < 0.001) and excursion (P < 0.01), but the relative contribution to LVFV increased from 18 ± 4 to 45 ± 13% (P < 0.001). Thus MA dynamics contribute substantially to LV diastolic filling. Although MA excursion and mean area change with moderate preload reduction and inotropic augmentation, the contribution of MA dynamics to total LVFV is constant with sizeable magnitude. With marked preload reduction (VCO), the contribution of MA dynamics to LVFV becomes even more important.

  • 54.
    Carlhäll, Carljohan
    et al.
    Linköping University, Department of Medicine and Care, Clinical Physiology. Linköping University, Faculty of Health Sciences.
    Lindström, Lena
    Linköping University, Department of Medicine and Care, Clinical Physiology. Linköping University, Faculty of Health Sciences.
    Wranne, Bengt
    Linköping University, Department of Medicine and Care, Clinical Physiology. Linköping University, Faculty of Health Sciences.
    Nylander, Eva
    Linköping University, Department of Medicine and Care, Clinical Physiology. Linköping University, Faculty of Health Sciences.
    Atrioventricular plane displacement correlates closely to circulatory dimensions but not to ejection fraction in normal young subjects2001In: Clinical Physiology, ISSN 0144-5979, E-ISSN 1365-2281, Vol. 21, no 5, p. 621-628Article in journal (Refereed)
    Abstract [en]

    Aims Mitral atrioventricular plane displacement (AVPD) provides information about left ventricular systolic function. M-mode of systolic annulus amplitude or tissue Doppler imaging of systolic annulus velocity are the current methods of evaluating AVPD. A correlation to ejection fraction (EF) has been demonstrated in patients with coronary artery disease and left ventricular dysfunction. Our aim was (i) to investigate the mitral AVPD of normal subjects with different physical work capacities and (ii) to further evaluate AVPD as an index of left ventricular systolic function.

    Methods and results Twenty-eight healthy men mean age 28 years (20–39) were included: endurance trained (ET) (n=10), strength trained (ST) (n=9) and untrained (UT) (n=9). The systolic AVPD was recorded at four sites, septal, lateral, anterior and posterior, using M-mode. Left ventricular volumes were calculated according to Simpson’s rule. Systolic AVPD was higher in endurance trained, 16·9 ± 1·5 mm, as compared with both strength trained, 13 ± 1·6 (P<0·001) and untrained, 14 ± 1·6 (P<0·001). Left ventricular systolic AVPD correlated strongly with end-diastolic volume (r=0·82), stroke volume (r=0·80) and maximal oxygen consumption per body weight (r=0·72). The correlation between AVPD and EF was poor (r=0·22).

    Conclusion  In the subjects studied, with a range of normal cardiac dimensions, AVPD correlated to stroke volume, end-diastolic volume and maximal oxygen consumption per body weight, but not to EF. On theoretical grounds, it also seems reasonable that a dimension like AVPD is related to other cardiac dimensions and volumes, rather than to a fraction, like EF. AVPD is one parameter that is useful for evaluation of left ventricular systolic function but is not interchangeable with other measurements such as EF.

  • 55.
    Carlhäll, Carljohan
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Physiology. Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Wigström, Lars
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Physiology. Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Heiberg, Einar
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Physiology. Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Karlsson, M.
    Östergötlands Läns Landsting, Centre for Medical Imaging, Department of Biomedical Engineering in Östergötland. Linköping University, Faculty of Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Bolger, A. F.
    Department of Medicine, Division of Cardiology, University of California, San Francisco, California, USA.
    Nylander, E.
    Linköping University, Department of Medicine and Care. Linköping University, Faculty of Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Reply to article: Misinterpretation About the Contribution of the Left Ventricular Long-Axis Shortening to the Stroke Volume2006In: American Journal of Physiology. Heart and Circulatory Physiology, ISSN 0363-6135, E-ISSN 1522-1539, Vol. 291, no 5, p. 2551-2552Article in journal (Other academic)
    Abstract [en]

       

  • 56.
    Carlhäll, Carljohan
    et al.
    Linköping University, Department of Medicine and Care, Clinical Physiology. Linköping University, Department of Medicine and Care, Center for Medical Image Science and Visualization. Linköping University, Faculty of Health Sciences.
    Wigström, Lars
    Linköping University, Department of Medicine and Care, Clinical Physiology. Linköping University, Department of Medicine and Care, Center for Medical Image Science and Visualization. Linköping University, Faculty of Health Sciences.
    Heiberg, Einar
    Linköping University, Department of Medicine and Care, Clinical Physiology. Linköping University, Department of Medicine and Care, Center for Medical Image Science and Visualization. Linköping University, Faculty of Health Sciences.
    Karlsson, Matts
    Linköping University, Department of Biomedical Engineering. Linköping University, Department of Medicine and Care, Center for Medical Image Science and Visualization. Linköping University, Faculty of Health Sciences.
    Bolger, A. F.
    Department of Medicine/Cardiology, University of California, San Francisco, California.
    Nylander, Eva
    Linköping University, Department of Medicine and Care, Clinical Physiology. Linköping University, Department of Medicine and Care, Center for Medical Image Science and Visualization. Linköping University, Faculty of Health Sciences.
    Contribution of mitral annular excursion and shape dynamics to total left ventricular volume change2004In: American Journal of Physiology. Heart and Circulatory Physiology, ISSN 0363-6135, E-ISSN 1522-1539, Vol. 287, no 4, p. H1836-H1841Article in journal (Refereed)
    Abstract [en]

    The mitral annulus (MA) has a complex shape and motion, and its excursion has been correlated to left ventricular (LV) function. During the cardiac cycle the annulus’ excursion encompasses a volume that is part of the total LV volume change during both filling and emptying. Our objective was to evaluate the contribution of MA excursion and shape variation to total LV volume change. Nine healthy subjects aged 56 ± 11 (means ± SD) years underwent transesophageal echocardiography (TEE). The MA was outlined in all time frames, and a four-dimensional (4-D) Fourier series was fitted to the MA coordinates (3-D+time) and divided into segments. The annular excursion volume (AEV) was calculated based on the temporally integrated product of the segments’ area and their incremental excursion. The 3-D LV volumes were calculated by tracing the endocardial border in six coaxial planes. The AEV (10 ± 2 ml) represented 19 ± 3% of the total LV stroke volume (52 ± 12 ml). The AEV correlated strongly with LV stroke volume (r = 0.73; P < 0.05). Peak MA area occurred during middiastole, and 91 ± 7% of reduction in area from peak to minimum occurred before the onset of LV systole. The excursion of the MA accounts for an important portion of the total LV filling and emptying in humans. These data suggest an atriogenic influence on MA physiology and also a sphincter-like action of the MA that may facilitate ventricular filling and aid competent valve closure. This 4-D TEE method is the first to allow noninvasive measurement of AEV and may be used to investigate the impact of physiological and pathological conditions on this important aspect of LV performance.

  • 57.
    Carlhäll, Carljohan
    et al.
    Linköping University, Department of Medicine and Care, Clinical Physiology. Linköping University, Faculty of Health Sciences.
    Wranne, Bengt
    Linköping University, Department of Medicine and Care, Clinical Physiology. Linköping University, Faculty of Health Sciences.
    Jurkevicius, R.
    Institute of Cardiology of Kaunas Medical University, Kaunas, Lithuania.
    Is left ventricular postsystolic long-axis shortening a marker for severity of hypertensive heart disease?2003In: American Journal of Cardiology, ISSN 0002-9149, E-ISSN 1879-1913, Vol. 91, no 12, p. 1490-1493Article in journal (Refereed)
    Abstract [en]

    No abstract available.

  • 58.
    Chew, Michelle
    et al.
    Departments of Anaesthesia and Intensive Care, Institute of Experimental Clinical Research, Skejby Sygehus, Aarhus University Hospital, Denmark.
    Brandberg, Joakim
    Linköping University, Department of Biomedical Engineering. Linköping University, The Institute of Technology.
    Bjarum, Steinar
    Department of Biomerical Engineering, Trondheim University, Norway.
    Baek-Jensen, Katrine
    Institute of Experimental Clinical Research, Skejby Sygehus, Aarhus University Hospital, Denmark.
    Sloth, Erik
    Departments of Anaesthesia and Intensive Care, Skejby Sygehus, Aarhus University Hospital, Denmark.
    Ask, Per
    Linköping University, Department of Biomedical Engineering. Linköping University, The Institute of Technology.
    Hasenkam, J. Michael
    Department of Cardiothoracic Surgery, Skejby Sygehus, Aarhus University Hospital, Denmark.
    Janerot Sjöberg, Birgitta
    Linköping University, Department of Medicine and Care, Clinical Physiology. Linköping University, Faculty of Health Sciences.
    Pediatric cardiac output measurement using surface integration of velocity vectors: an in vivo validation study2000In: Critical Care Medicine, ISSN 0090-3493, E-ISSN 1530-0293, Vol. 28, no 11, p. 3664-3671Article in journal (Refereed)
    Abstract [en]

    Objective: To test the accuracy and reproducibility of systemic cardiac output (CO) measurements using surface integration of velocity vectors (SIVV) in a pediatric animal model with hemodynamic instability and to compare SIVV with traditional pulsed-wave Doppler measurements.

    Design: Prospective, comparative study.

    Setting: Animal research laboratory at a university medical center.

    Subjects: Eight piglets weighing 10-15 kg.

    Interventions: Hemodynamic instability was induced by using inhalation of isoflurane and infusions of colloid and dobutamine.

    Measurements: SIVV CO was measured at the left ventricular outflow tract, the aortic valve, and ascending aorta. Transit time CO was used as the reference standard.

    Results: There was good agreement between SIVV and transit time CO. At high frame rates, the mean difference ± 2 sd between the two methods was 0.01 ± 0.27 L/min for measurements at the left ventricular outflow tract, 0.08 ± 0.26 L/min for the ascending aorta, and 0.06 ± 0.25 L/min for the aortic valve. At low frame rates, measurements were 0.06 ± 0.25, 0.19 ± 0.32, and 0.14 ± 0.30 L/min for the left ventricular outflow tract, ascending aorta, and aortic valve, respectively. There were no differences between the three sites at high frame rates. Agreement between pulsed-wave Doppler and transit time CO was poorer, with a mean difference ± 2 sd of 0.09 ± 0.93 L/min. Repeated SIVV measurements taken at a period of relative hemodynamic stability differed by a mean difference ±2 sd of 0.01 ± 0.22 L/min, with a coefficient of variation = 7.6%. Intraobserver coefficients of variation were 5.7%, 4.9%, and 4.1% at the left ventricular outflow tract, ascending aorta, and aortic valve, respectively. Interobserver variability was also small, with a coefficient of variation = 8.5%.

    Conclusions: SIVV is an accurate and reproducible flow measurement technique. It is a considerable improvement over currently used methods and is applicable to pediatric critical care.

  • 59.
    Chew, Michelle
    et al.
    Faculty of Health Science University of Aarhus, Denmark.
    Brandberg, Joakim
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Physiological Measurements.
    Janerot-Sjöberg, Birgitta
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Physiology. Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Sloth, Erik
    Aarhus University Hospital Aarhus Denmark.
    Ask, Per
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Physiological Measurements.
    Hasenkam, Michael
    Aarhus University Hospital Aarhus Denmark.
    Noninvasive cardiac output measurement using Doppler echocardiography; current status and future perspective using Surface Integration of Velocity Vectors (SIVV)1999In: Danish Society of Anesthesiologists,1999, 1999Conference paper (Other academic)
  • 60.
    Chew, Michelle
    et al.
    University of Aarhus Denamrk.
    Brandberg, Joakim
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Physiological Measurements.
    Sloth, Erik
    Aarhus University Hospital Aarhus Denmark.
    Ask, Per
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Physiological Measurements.
    Janerot-Sjöberg, Birgitta
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Physiology. Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Non-invasive cardiac output measurement using colour Doppler ultrasound - the SIVV approach1999In: Acta Anaesthesiologica Scandinavica, ISSN 0001-5172, E-ISSN 1399-6576, Vol. 114, p. 91-92Article in journal (Refereed)
  • 61.
    Dahlin, Lars-Göran
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Thoracic Surgery. Östergötlands Läns Landsting, Heart Centre, Department of Thoracic and Vascular Surgery.
    Kågedahl, Bertil
    Nylander, Eva
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Physiology. Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Olin, Christian
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Thoracic Surgery. Östergötlands Läns Landsting, Heart Centre, Department of Thoracic and Vascular Surgery.
    Rutberg, Hans
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Anaesthesiology. Östergötlands Läns Landsting, Heart Centre, Department of Thoracic and Vascular Surgery.
    Svedjeholm, Rolf
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Thoracic Surgery. Östergötlands Läns Landsting, Heart Centre, Department of Thoracic and Vascular Surgery.
    Unspecific elevation of plasma troponin-T after coronary surgery. Abstract 17th Annual meeting EACTA, 2002 June 12-15, Dublin Ireland2002In: EACTA Abstracts 2002,2002, 2002Conference paper (Refereed)
  • 62.
    Dahlin, Lars-Göran
    et al.
    Linköping University, Department of Medicine and Care, Thoracic Surgery. Linköping University, Faculty of Health Sciences.
    Kågedal, Bertil
    Linköping University, Department of Biomedicine and Surgery, Clinical Chemistry. Linköping University, Faculty of Health Sciences.
    Nylander, Eva
    Linköping University, Department of Medicine and Care, Clinical Physiology. Linköping University, Faculty of Health Sciences.
    Olin, Christian
    Linköping University, Department of Medicine and Care, Thoracic Surgery. Linköping University, Faculty of Health Sciences.
    Rutberg, Hans
    Linköping University, Department of Medicine and Care, Anaesthesiology. Linköping University, Faculty of Health Sciences.
    Svedjeholm, Rolf
    Linköping University, Department of Medicine and Care, Thoracic Surgery. Linköping University, Faculty of Health Sciences.
    An attempt to quantify the plasma levels of troponin-T and CK-MB after coronary surgery caused by release unrelated to permanent myocardial injuryManuscript (preprint) (Other academic)
    Abstract [en]

    Background: Release of biochemical markers of myocardial injury unrelated to permanent myocardial damage has been claimed to explain a major proportion of elevations seen after cardiac surgery. However, little is known about the magnitude of this unspecific release. The aim of this study was to shed light on this issue by serial measurements in patients without permanent myocardial injury after coronary surgery.

    Methods: The unique release kinetics of troponin-T were employed to identify patients with no or minimal permanent myocardial injury. 302 patients undergoing CABG procedures (employing cardiopuhnonary bypass, crystalloid cardioplegia and retransfusion of shed mediastinal blood) were studied.

    Results: 90 patients were found to have normalized troponin-T levels no later than the fourth postoperative day indicating that early elevation of biochemical markers was explained almost purely by unspecific release. In this subgroup troponin-T (2.03±1.36 µg/L; range 0.35-8.99 µg/L) peaked at the 3 hour recording and CK-MB (28.3±10.7 µg/L; range 11.9-86 µg/L) peaked at the 8 hour recording after unclamping the aorta.

    Conclusions: A substantial early release of CK-MB and troponin-T occurred in patients with no or minimal permanent myocardial injury after CABG. The time frame when unspecific release was most pronounced is frequently studied to evaluate myocardial protective strategies or to compare different treatment modalities. Also, differences in unspecific release of biochemical markers can be expected depending on type of surgical procedure or coronary intervention. Therefore, further efforts to hring clarity about diagnostic pitfalls are warranted to prevent inappropriate comparisons and to improve our assessment of myocardial damage in association with revascularisation procedures.

  • 63.
    Dahlin, Lars-Göran
    et al.
    Linköping University, Department of Medicine and Care, Thoracic Surgery. Linköping University, Faculty of Health Sciences.
    Kågedal, Bertil
    Linköping University, Department of Biomedicine and Surgery, Clinical Chemistry. Linköping University, Faculty of Health Sciences.
    Nylander, Eva
    Linköping University, Department of Medicine and Care, Clinical Physiology. Linköping University, Faculty of Health Sciences.
    Olin, Christian
    Linköping University, Department of Medicine and Care, Clinical Physiology. Linköping University, Faculty of Health Sciences.
    Rutberg, Hans
    Linköping University, Department of Medicine and Care, Anaesthesiology. Linköping University, Faculty of Health Sciences.
    Svedjeholm, Rolf
    Linköping University, Department of Medicine and Care, Thoracic Surgery. Linköping University, Faculty of Health Sciences.
    Early Identification of Permanent Myocardial Damage after Coronary Surgery is Aided by Repeated Measurements of CK-MB2002In: Scandinavian Cardiovascular Journal, ISSN 1401-7431, E-ISSN 1651-2006, Vol. 36, no 1, p. 35-40Article in journal (Refereed)
    Abstract [en]

    Objective - ECG diagnosis of myocardial infarction after cardiac surgery is associated with major pitfalls and enzyme diagnosis is interfered by unspecific elevation unrelated to permanent myocardial injury. Sustained release of troponin-T is a marker of permanent myocardial injury if renal function is maintained. However, early identification of perioperative myocardial infarction is desirable and therefore the usefulness of creatine kinase monobasic (CK-MB) kinetics to detect myocardial injury early after coronary surgery was investigated.

    Design - Two hundred and eighty-six patients undergoing coronary surgery were studied with respect to release of enzymes and troponin-T preoperatively and postoperatively 3 and 8 h after unclamping the aorta, and every morning postoperative days 1-4.

    Results - CK-MB peak was found at 3 h ( n = 145), 8 h ( n = 103) and 16-20 h after unclamping ( n = 38). Depending on when the CK-MB peak was recorded different demographic and perioperative characteristics were found. A sustained release of troponin-T was characteristic for the group with the CK-MB peak at 16-20 h after unclamping.

    Conclusion - If CK-MB is measured only once it may be advisable to do it on the first postoperative morning as these measurements provided the best discrimination between patients with and without sustained elevation of troponin-T. However, repeated sampling provides additional information that aids in the early identification of permanent myocardial injury particularly in patients with borderline elevations of CK-MB.

  • 64.
    Dahlin, Lars-Göran
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Thoracic Surgery. Östergötlands Läns Landsting, Heart Centre, Department of Thoracic and Vascular Surgery.
    Kågedal, Bertil
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Biomedicine and Surgery, Clinical Chemistry. Östergötlands Läns Landsting, Centre for Laboratory Medicine, Department of Clinical Chemistry.
    Nylander, Eva
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Physiology. Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Olin, Christian
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Thoracic Surgery.
    Rutberg, Hans
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Anaesthesiology. Östergötlands Läns Landsting, Heart Centre, Department of Thoracic and Vascular Surgery.
    Svedjeholm, Rolf
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Thoracic Surgery. Östergötlands Läns Landsting, Heart Centre, Department of Thoracic and Vascular Surgery.
    Unspecific elevation of plasma troponin-T and CK-MB after coronary surgery2003In: Scandinavian Cardiovascular Journal, ISSN 1401-7431, E-ISSN 1651-2006, Vol. 37, no 5, p. 283-287Article in journal (Refereed)
    Abstract [en]

    Objective - Biochemical markers of myocardial injury are frequently elevated after cardiac surgery. It is generally accepted that release unrelated to permanent myocardial damage explains a proportion of these elevations. However, little is known about the magnitude and temporal characteristics of this diagnostic noise. One way to address this issue would be to study a group without permanent myocardial injury. Design - The unique release kinetics of troponin-T (permanent myocardial injury causes a sustained release of structurally bound troponin) were used to identify patients with no or minimal permanent myocardial injury. Blood was sampled from patients undergoing coronary artery bypass grafting (CABG) with cardiopulmonary bypass (CPB) before surgery, 3 and 8 h after unclamping the aorta, and each morning until postoperative day 4, for analysis of enzymes and troponin-T. From 302 consecutive patients a subgroup was identified that fulfilled the following criteria: (a) normalized troponin-T levels =postoperative day 4, (b) no ECG changes indicating myocardial injury. Results - Seventy-seven patients fulfilled the criteria above and in this subgroup troponin-T (2.08 ▒ 1.42 ╡g/ 1, range 0.35-8.99 ╡g/l) peaked at the 3 h recording and creatine kinase monobasic (CK-MB) (28.6 ▒ 11.3 ╡g/l, range 11.9-86.0 ╡g/l) peaked at the 8 h recording after unclamping the aorta. Conclusion - Substantial early elevations of plasma CK-MB and troponin-T occurred in patients with no or minimal permanent myocardial injury after CABG. Unspecific release was most pronounced during the timeframe that is usually studied to evaluate myocardial protective strategies or to compare revascularization procedures.

  • 65.
    Debasso, Rachel
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Physiology.
    Åstrand, Håkan
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Physiology.
    Bjarnegård, Niclas
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Physiology.
    Ryden Ahlgren, A
    Sandgren, T
    Länne, Toste
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care. Östergötlands Läns Landsting, Heart Centre, Department of Thoracic and Vascular Surgery.
    The popliteal artery, an unusual muscular artery with wall properties similar to the aorta: Implications for susceptibility to aneurysm formation?2004In: Journal of Vascular Surgery, ISSN 0741-5214, E-ISSN 1097-6809, Vol. 39, no 4, p. 836-842Article in journal (Refereed)
    Abstract [en]

    Objective: The popliteal artery is, after the aorta, the most common site for aneurysm formation. Why the popliteal artery is more susceptible than other peripheral muscular arteries is unknown. An important factor may be differences in arterial wall composition as compared with other peripheral muscular arteries, which in turn affect wall properties. These are however unknown. We studied the mechanical wall properties of the popliteal artery in healthy subjects. Material and Methods: An ultrasound echo-tracking system was used to measure pulsatile changes in popliteal diameter in 108 healthy subjects (56 female, 52 male, age range, 9-82 years). In combination with blood pressure, stiffness (β), strain, cross-sectional artery wall compliance coefficient (CC), and distensibility coefficient (DC) were calculated. Intima-media thickness (IMT) was registered with a Philips P700 ultrasound scanner. Results: The popliteal diameter increased with age, and was larger in male subjects than in female subjects (P < .001). Fractional diameter change (strain) decreased with age (P < .001), and strain values were lower in male subjects than in female subjects (P < .01). Accordingly, stiffness increased with age (P < .001), with higher stiffness values in male subjects (P < .01). DC decreased with age (P < .001), with lower DC values in male subjects (P < .01). CC decreased with age, with no difference between genders (P < .001). IMT increased with age (P < .001), with higher IMT values in male subjects (P < .001). The increase in IMT did not affect distensibility. Conclusion: The wall properties of the popliteal artery are affected by age and gender, not only with an increase in diameter, but also with an age-related decrease in distensibility, with male subjects having lower distensibility than in female subjects. This seems not to be the behavior of a true muscular artery, but of a central elastic artery, such as the aorta, and might have implications for susceptibility to arterial dilatation, as well as the association of aneurysm formation between the aorta and the popliteal artery.

  • 66.
    Dyverfeldt, Petter
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Physiology. Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Escobar Kvitting, John-Peder
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Physiology. Östergötlands Läns Landsting, Centre of Surgery and Oncology, Department of Surgery in Östergötland.
    Sigfridsson, Andreas
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Physiology. Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Engvall, Jan
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Physiology. Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Bolger, Ann F
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Physiology.
    Ebbers, Tino
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Physiology. Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Assessment of Turbulent Flow using Magnetic Resonance Imaging2007In: IX Svenska Kardiovaskulära Vårmötet,2007, 2007Conference paper (Other academic)
    Abstract [en]

      

  • 67.
    Dyverfeldt, Petter
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Health Sciences, Clinical Physiology . Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Escobar Kvitting, John-Peder
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Physiology. Östergötlands Läns Landsting, Centre of Surgery and Oncology, Department of Surgery in Östergötland.
    Sigfridsson, Andreas
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Health Sciences, Clinical Physiology . Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Engvall, Jan
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Health Sciences, Clinical Physiology . Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Bolger, Ann F
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Health Sciences, Clinical Physiology . Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Ebbers, Tino
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Health Sciences, Clinical Physiology . Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Improved image acquisition and processing allow accurate 4D flow investigations of the right ventricle2008In: Medicinteknikdagarna,2008, 2008Conference paper (Other academic)
    Abstract [en]

      

  • 68.
    Dyverfeldt, Petter
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Physiology. Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Sigfridsson, Andreas
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Physiology. Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Escobar Kvitting, John-Peder
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Physiology. Östergötlands Läns Landsting, Centre of Surgery and Oncology, Department of Surgery in Östergötland.
    Ebbers, Tino
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Physiology. Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Quantification of Turbulence Intensity by Generalizing Phase-Contrast MRI2006In: Proc. Intl. Soc. Mag. Reson. Med. 14,2006, 2006, p. 870-870Conference paper (Refereed)
    Abstract [en]

      

  • 69.
    Ebbers, Tino
    et al.
    Linköping University, Department of Biomedical Engineering. Linköping University, The Institute of Technology.
    Brandt, Einar
    Linköping University, Department of Biomedical Engineering. Linköping University, Department of Medicine and Care, Clinical Physiology. Linköping University, Faculty of Health Sciences.
    Wigström, Lars
    Linköping University, Department of Biomedical Engineering. Linköping University, Department of Medicine and Care, Clinical Physiology. Linköping University, The Institute of Technology.
    Karlsson, Matts
    Linköping University, Department of Biomedical Engineering. Linköping University, The Institute of Technology.
    Myocordial segmentation of time-resolved 3D phase-contrast MRIManuscript (preprint) (Other academic)
    Abstract [en]

    Time-resolved three-dimensional (3D) phase-contrast MRI can be used to study 3D cardiac blood flow patterns and myocardial motion. The image contrast between myocardium and blood in 3D MRl is often inadequate for clear orientation and border delineation, however. To improve the accuracy and ease of segmentation, we developed a method based on a particle trace technique for time-resolved 3D cardiac velocity vector fields. A particle trace trajectory that follows the blood flow and the myocardial motion is obtained by integration of the velocity field over time. The myocardium can be differentiated by using the magnitude image data in combination with the trajectory's velocities and the expected behavior of the myocardial particle traces, that is, that traces starting in the myocardium will return to their starting point at the end of a cardiac cycle. The myocardial probability obtained in this way can be used for visualization, which eliminates the need for acquiring additional two-dimensional images. It also serves as the basis for border delineation, allowing quantification of important clinical parameters such as ventricular volume and mass.

  • 70.
    Ebbers, Tino
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Physiology. Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Fyrenius, Anna
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Physiology.
    Wigström, Lars
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Physiology. Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Bolger, Ann F
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Physiology. Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Karlsson, Matts
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Modelling and Simulation .
    Calculation of relative cardiac pressure along streamlines using time-resolved 3D phase contrast MRI1999In: Journal of Cardiovascular Magnetic Resonance,1999, 1999, p. 290-291Conference paper (Other academic)
  • 71.
    Ebbers, Tino
    et al.
    Linköping University, Department of Biomedical Engineering. Linköping University, The Institute of Technology.
    Wigström, Lars
    Linköping University, Department of Biomedical Engineering. Linköping University, Department of Medicine and Care, Clinical Physiology. Linköping University, Faculty of Health Sciences.
    Bolger, Ann
    Department of Medicine, University of California−San Francisco, San Francisco, CA.
    Engvall, Jan
    Linköping University, Department of Medicine and Care, Clinical Physiology. Linköping University, Faculty of Health Sciences.
    Karlsson, Matts
    Linköping University, Department of Biomedical Engineering. Linköping University, The Institute of Technology.
    Estimation of relative cardiovascular pressures using time-resolved three-dimensional phase contrast MRI2001In: Magnetic Resonance in Medicine, ISSN 0740-3194, E-ISSN 1522-2594, Vol. 45, no 5, p. 872-879Article in journal (Refereed)
    Abstract [en]

    Accurate, easy-to-use, noninvasive cardiovascular pressure registration would be an important addition to the diagnostic armamentarium for assessment of cardiac function. A novel noninvasive and three-dimensional (3D) technique for estimation of relative cardiovascular pressures is presented. The relative pressure is calculated using the Navier-Stokes equations along user-defined lines placed within a time-resolved 3D phase contrast MRI dataset. The lines may be either straight or curved to follow an actual streamline. The technique is validated in an in vitro model and tested on in vivo cases of normal and abnormal transmitral pressure differences and intraaortic flow. The method supplements an intuitive visualization technique for cardiovascular flow, 3D particle trace visualization, with a quantifiable diagnostic parameter estimated from the same dataset.

  • 72.
    Ebbers, Tino
    et al.
    Linköping University, Department of Medicine and Care, Clinical Physiology. Linköping University, Department of Biomedical Engineering. Linköping University, Faculty of Health Sciences.
    Wigström, Lars
    Linköping University, Department of Medicine and Care, Clinical Physiology. Linköping University, Department of Biomedical Engineering. Linköping University, Faculty of Health Sciences.
    Bolger, Ann
    Department of Medicine, University of California, San Francisco, CA.
    Wranne, Bengt
    Linköping University, Department of Medicine and Care, Clinical Physiology. Linköping University, Faculty of Health Sciences.
    Karlsson, Matts
    Linköping University, Department of Biomedical Engineering. Linköping University, Faculty of Health Sciences.
    Noninvasive measurement of time-varying three-dimensional relative pressure fields within the human heart2002In: Journal of Biomechanical Engineering, ISSN 0148-0731, E-ISSN 1528-8951, Vol. 124, no 3, p. 288-293Article in journal (Refereed)
    Abstract [en]

    Understanding cardiac blood flow patterns is important in the assessment of cardiovascular function. Three-dimensional flow and relative pressure fields within the human left ventricle are demonstrated by combining velocity measurements with computational fluid mechanics methods. The velocity field throughout the left atrium and ventricle of a normal human heart is measured using time-resolved three-dimensional phase-contrast MRL. Subsequently, the time-resolved three-dimensional relative pressure is calculated from this velocity field using the pressure Poisson equation. Noninvasive simultaneous assessment of cardiac pressure and flow phenomena is an important new tool for studying cardiac fluid dynamics.

  • 73.
    Ebbers, Tino
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Physiology. Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Wigström, Lars
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Physiology. Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Fyrenius, Anna
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Physiology.
    Bolger, Ann F
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Physiology. Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Karlsson, Matts
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Modelling and Simulation .
    Particle trace visualization of cardiac flow patterns using 3D phase contrast MRI: an in vitro comparison with streamlines created using dye.1999In: Proc Intl Soc Magn Reson Med 7,1999, 1999, p. 2025-2025Conference paper (Other academic)
  • 74. EIDENVALL, L
    et al.
    Ask, Per
    Linköping University, Department of Biomedical Engineering, Physiological Measurements. Linköping University, The Institute of Technology.
    Loyd, Dan
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, The Institute of Technology.
    Wranne, Bengt
    Linköping University, Department of Medicine and Care, Clinical Physiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Clinical Physiology in Linköping.
    DETERMINATION OF REGURGITANT FLOW IN A PULSATILE MODEL BY INTEGRATING VELOCITIES FROM THE ENTIRE 3D PROXIMAL VELOCITY-FIELD1993In: Circulation, ISSN 0009-7322, E-ISSN 1524-4539, Vol. 88, no 4, 2Article in journal (Refereed)
  • 75.
    Eidenvall, Lars
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Physiological Measurements.
    Ask, Per
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Physiological Measurements.
    Loyd, Dan
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering, Applied Thermodynamics and Fluid Mechanics.
    Wranne, Bengt
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Physiology. Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Determination of regurgitant flow and volume by integrating actual proximal velocities over hemispheres (IPROV) in two orthogonal planes1996In: Journal of the American Society of Echocardiography, ISSN 0894-7317, E-ISSN 1097-6795, Vol. 9, no 4, p. 527-538Article in journal (Refereed)
  • 76.
    Eidenvall, Lars
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Physiological Measurements.
    Ask, Per
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Physiological Measurements.
    Loyd, Dan
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering, Applied Thermodynamics and Fluid Mechanics.
    Wranne, Bengt
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Physiology. Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Determination of regurgitant flow in a pulsatile model by integrating velocities from the entire 3D proximal velocity field1992In: American Heart Association,1993, 1992Conference paper (Refereed)
  • 77.
    Eidenvall, Lars
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Physiological Measurements.
    Barclay, S A
    Loyd, Dan
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering, Applied Thermodynamics and Fluid Mechanics.
    Wranne, Bengt
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Physiology. Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Ask, Per
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Physiological Measurements.
    Regurgitant heart valve flow from 3D proximal velocity field - continued search for the ideal method1995In: Medical & Biological Engineering & Computing, ISSN 0140-0118, Vol. 33, p. 131-139Article in journal (Refereed)
  • 78.
    Eidenvall, Lars E. J.
    Linköping University, Department of Biomedical Engineering. Linköping University, Department of Medicine and Care, Clinical Physiology. Linköping University, Department of Mechanical Engineering. Linköping University, The Institute of Technology.
    Cardiovascular modelling and ultrasound heart flow quantification: aortic flow and mitral regurgitation1993Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The primary objective of this thesis was to model and simulate aortic flow and mitral regurgitation and to improve quantitative ultrasound measurements. The tools used were; theoretical analysis, computer simulation, model experiments, image analysis and clinical evaluation.

    The flow in the aorta is known to be influenced by both cardiac function and vascular characteristics. The influence of vascular characteristics were investigated in a three parameter windkessel model. Peak aortic velocity and acceleration were studied when these parameters were changed. The results indicate that aortic peak flow velocity is related to the compliance of the arterial system while the peak flow acceleration is inversely related to the characteristic impedance of the aorta and large vessels.

    To obtain a correct aortic flow velocity profile from a two dimensional colour flow echocardiographic investigation, a unit which incrementally delayed the ECG signal was designed and used to control the ultrasound scanning. By combining velocity data from incrementally delayed images in a software program, a time corrected profile was obtained.

    In order to determine regurgitant heart valve flow volume, the intensity of the ultrasound continuous wave signal has been suggested as a potential method. Measurements in a hydraulic model showed, however, that the intensity of the signal was, in addition to volume, also related to peak velocity, measuring angle and machine settings. Hence, conclusions drawn about regurgitant grade from the intensity signal require caution.

    Another method for determination of valve regurgitation is to study the laminar and nondisturbed flow in the region of acceleration proximal to the valve, normally the distance from orifice to the first aliased velocity. This was tested first in a steady flow model using colour M mode and colour 2D information, and later in a pulsatile flow model. Four different methods using velocity data from the entire reconstructed 2D velocity vector field were investigated. Model experiments and error calculation showed that flow was best determined by integrating velocities along hemi-spherical lines in two perpendicular planes within an angle of ±45° from the orifice centre line at a distance of approximately 1.2 to 1.4 times the orifice diameter, corresponding to velocities between 0.15 and 0.45 m/s. By combining 2D flow and spectral velocity data, regurgitant volume could be estimated for both circular, diagonal and crescent orifices to within + 15 to -11% from true volume.

  • 79.
    Eidenvall, Lars
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Physiological Measurements.
    Janerot-Sjöberg, Birgitta
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Physiology. Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Ask, Per
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Physiological Measurements.
    Loyd, Dan
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering, Applied Thermodynamics and Fluid Mechanics.
    Wranne, Bengt
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Physiology. Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    2D Doppler Flowvelocity profiles can be time corrected with an external ECG delay device1992In: Journal of the American Society of Echocardiography, ISSN 0894-7317, E-ISSN 1097-6795, Vol. 5, p. 405-413Article in journal (Refereed)
  • 80. Eidenvall, Lars
    et al.
    Sjöberg, Birgitta Janero
    Linköping University, Department of Medical and Health Sciences, Clinical Physiology. Linköping University, Faculty of Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV). Östergötlands Läns Landsting, Heart and Medicine Center, Department of Clinical Physiology in Linköping.
    Ask, Per
    Linköping University, Department of Biomedical Engineering, Physiological Measurements. Linköping University, The Institute of Technology.
    Loyd, Dan
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, The Institute of Technology.
    Wranne, Bengt
    Linköping University, Department of Medicine and Care, Clinical Physiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Clinical Physiology in Linköping.
    Two-dimensional color Doppler flow velocity profiles can be time corrected with an external ECG-delay device.1992In: Journal of the American Society of Echocardiography, ISSN 0894-7317, E-ISSN 1097-6795, Vol. 5, no 4, p. 405-413Article in journal (Refereed)
    Abstract [en]

    Although two-dimensional ultrasound color flow imaging is often considered to be a real-time technique, the acquisition time for two-dimensional color images may be up to 200 msec. Time correction is therefore necessary to obtain correct flow velocity profiles. We have developed a time-correction method in which a specially designed unit detects the QRS complex from the patient and creates a trig pulse that is delayed incrementally in relation to the QRS complex. This trig pulse controls the acquisition of the ultrasound images. A number of consecutively delayed images, with known incremental delay between the sweeps, can thus be stored in the memory of the echocardiograph and transferred digitally to a computer. The time-corrected flow velocity profile is obtained by interpolation of data from the time-delayed profiles. The system was evaluated in a Doppler string phantom test. With this technique it is possible to study time-corrected flow velocity profiles without the need to alter existing ultrasound Doppler equipment.

  • 81. Eidenvall, Lars
    et al.
    Sjöberg, Birgitta Janero
    Linköping University, Department of Medical and Health Sciences, Clinical Physiology. Linköping University, Faculty of Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV). Östergötlands Läns Landsting, Heart and Medicine Center, Department of Clinical Physiology in Linköping.
    Wranne, Bengt
    Linköping University, Department of Medicine and Care, Clinical Physiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Clinical Physiology in Linköping.
    Loyd, Dan
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, The Institute of Technology.
    Ask, Per
    Linköping University, Department of Biomedical Engineering, Physiological Measurements. Linköping University, The Institute of Technology.
    INFORMATION IN THE AORTIC BLOOD VELOCITY SIGNAL - A SIMULATION STUDY1991In: PROCEEDINGS OF THE ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY, VOL 13, PTS 1-5, 1991, p. 2248-2249Conference paper (Refereed)
  • 82.
    Eintrei, Christina
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Anaesthesiology. Östergötlands Läns Landsting, Anaesthesiology and Surgical Centre, Department of Intensive Care UHL.
    Bergdahl, Björn
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care. Östergötlands Läns Landsting, Heart Centre, Department of Cardiology.
    Fyrenius, Anna
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Physiology.
    Hultman, Per
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Molecular and Clinical Medicine, Molecular and Immunological Pathology. Östergötlands Läns Landsting, Centre for Laboratory Medicine, Department of Clinical Pathology and Clinical Genetics.
    Theodorsson, Elvar
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Biomedicine and Surgery, Division of clinical chemistry. Östergötlands Läns Landsting, Centre for Laboratory Medicine, Department of Clinical Chemistry.
    Revising a medical PBL-curriculum - the Linköping strategy2004In: Association for Medical Education in Europe,2004, 2004Conference paper (Other academic)
  • 83.
    Ekberg, Stefan
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Radiation Physics. Östergötlands Läns Landsting, Centre of Surgery and Oncology, Department of Radiation Physics.
    Olsson, Anna
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Radiation Physics.
    Hellerström, Sabine
    Linköping University, Department of Medicine and Care, Clinical Physiology. Östergötlands Läns Landsting, Heart Centre, Department of Cardiology.
    Quality control of gamma cameras with statistical process control2004In: European Association of Nuclear Medicine,2004, 2004Conference paper (Other academic)
  • 84.
    Ekelund, Ulf
    et al.
    Unit of Preventive Nutrition, Department of Medical Nutrition / Biosciences, Karolinska Institutet, Stockholm, Sweden and Department of Physical Education and Health, Örebro University, Örebro, Sweden.
    Tingström, Pia
    Linköping University, Department of Medicine and Care, Cardiology. Linköping University, Faculty of Health Sciences.
    Kamwendo, Kitty
    Department of Caring Sciences, Örebro University, Örebro, Sweden.
    Krantz, Monica
    Linköping University, Faculty of Health Sciences.
    Nylander, Eva
    Linköping University, Department of Medicine and Care, Clinical Physiology. Linköping University, Faculty of Health Sciences.
    Sjöström, Michael
    Unit of Preventive Nutrition, Department of Medical Nutrition / Biosciences, Karolinska Institutet, Stockholm, Sweden.
    Bergdahl, Björn
    Linköping University, Department of Medicine and Care, Cardiology. Linköping University, Faculty of Health Sciences.
    The validity of the Computer Science and Applications activity monitor for use in coronary artery disease patients during level walking2002In: Clinical Physiology and Functional Imaging, ISSN 1475-0961, E-ISSN 1475-097X, Vol. 22, no 4, p. 248-253Article in journal (Refereed)
    Abstract [en]

    The principal aim of the present study was to examine the validity of the Computer Science and Applications (CSA) activity monitor during level walking in coronary artery disease (CAD) patients. As a secondary aim, we evaluated the usefulness of two previously published energy expenditure (EE) prediction equations. Thirty-four subjects (29 men and five women), all with diagnosed CAD, volunteered to participate. Oxygen uptake (VO2) was measured by indirect calorimetry during walking on a motorized treadmill at three different speeds (3·2, 4·8 and 6·4 km h−1). Physical activity was measured simultaneously using the CSA activity monitor, secured directly to the skin on the lower back (i.e. lumbar vertebrae 4–5) with an elastic belt. The mean (±SD) activity counts were 1208 ± 429, 3258 ± 753 and 5351 ± 876 counts min−1, at the three speeds, respectively (P<0·001). Activity counts were significantly correlated to speed (r=0·92; P<0·001), VO2 (ml kg−1 min−1; r=0·87; P<0·001) and EE (kcal min−1; r=0·85, P<0·001). A stepwise linear regression analysis showed that activity counts and body weight together explained 75% of the variation in EE. Predicted EE from previously published equations differed significantly when used in this group of CAD patients. In conclusion, the CSA activity monitor is a valid instrument for assessing the intensity of physical activity during treadmill walking in CAD patients. Energy expenditure can be predicted from body weight and activity counts.

  • 85.
    Ekman, A
    et al.
    Kalmar.
    Brudin, Lars
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Physiology.
    Sandin, R
    Kalmar.
    A comparison of bispectral index and rapidly extracted auditory evoke potentials index responses to noxious stimulation during sevoflurane anesthesia2004In: Anesthesia and Analgesia, ISSN 0003-2999, E-ISSN 1526-7598, Vol. 99, p. 1141-1146Article in journal (Refereed)
    Abstract [en]

       

  • 86.
    Emilsson, Kent
    Linköping University, Department of Medicine and Care, Clinical Physiology. Linköping University, Faculty of Health Sciences.
    Mitral annulus motion in left ventricular pumping2001Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis focus on the role of the mitral annulus motion (MAM) versus outer contour changes in the short axis, in left ventricular (LV) pumping. The influence of atrial contraction on LV dimensions and volumes and the relation between MAM and ejection fraction (EF) in sinus rhythm and in atrial fibrillation was also studied.

    Echocardiography was used in all studies and in the study about circumflex artery motion angiography was also used.

    In a study including 20 healthy adults the role of MAM, i.e. the systolic shortening of the left ventricle in the long axis, as the main mechanism of LV pumping was confirmed. There was also, however, a significant contribution to the stroke volume from an outer contour decrease in the short axis during systole. At the chordae tendineae level a cross sectional area decrease of 24% was measured. From calculations based on measures of the long axis shortening of the LV, the outer short axis diameter of the LV and calculated stroke volume, a mean systolic cross sectional area decrease of about 6% was found along the whole length of the ventricle. The higher cross-sectional area decrease at the chordae level is thougth to be caused by regional differences.

    In previous studies the relation between EF and MAM has been assumed to be linear, but in a meta-analysis of 434 patients it was shown that the relation is non-linear and that a linear regression model overestimates EF in the low range of MAM. It was shown that the relation between EF and MAM in adults is influenced by age but only in the normal range of EF or MAM and not in patients with decreased EF (EF <0.5 or MAM < 10mm). The relation was also shown to be influenced by the LV wall thickness.

    In 20 patients with atrial fibrillation the ratio EF/MAM was shown to be higher than in 20 age- and gender matched patients with sinus rhythm, due to a decrease in MAM, caused by the loss of atrial contraction.

    The relation between EF and MAM is thus complex and it therefore seems logical not to "translate" MAM to EF. MAM should be used as such related to reference values in the assessment of LV systolic function.

    In 13 patients who had atrial fibrillation the stroke volume was shown to increase after successful direct-current cardioversion due to an increase in long axis diastolic elongation of the LV and thereby increased diastolic volume, when atrial contraction was regained.

    In 28 patients the angiographic measure of circumflex artery motion amplitude tended to be higher than MAM in the higher range of amplitudes while the opposite was found in the lower range of amplitudes.

    In 13 patients with normal EF it was shown that the motion amplitude of a site epicardially at the most basal lateral part of the LV wall was significantly (P < 0.001) higher than endocardially, but in 13 patients with decreased EF (< 0.5) there was no significant difference between the two sites. The motion amplitude epicardially corresponds to the motion amplitude of the circumflex artery.

    In the 13 patients with normal EF the motion amplitude of the closed mitral valves was significantly lower than the motion amplitude epi- and endocardially during systole, with a rather conic shape of the atrioventricular plane at the onset of systole. In end-systole the different parts of the left atrioventricular plane, the epicardial part, the endocardial part (mitral annulus) and the valves were almost on the same level.

    List of papers
    1. The mode of left ventricular pumping: is there an outer contour change in addition to the atrioventricular plane displacement?
    Open this publication in new window or tab >>The mode of left ventricular pumping: is there an outer contour change in addition to the atrioventricular plane displacement?
    2001 (English)In: Clinical Physiology, ISSN 0144-5979, E-ISSN 1365-2281, Vol. 21, no 4, p. 437-446Article in journal (Refereed) Published
    Abstract [en]

    The outer contour of the heart has in some studies been shown to be constant during the heart cycle and the epicardial apex almost stationary whilst the base of the ventricles moves towards apex during systole. The base of the left ventricle has been regarded as a cylinder with constant cross-sectional area with changes in height during the heart cycle, the latter corresponding to the amplitude of mitral annulus motion (MAM). In this echocardiographic study, including 20 healthy adults, the stroke volume calculated by the cylinder model was significantly lower than by a reference method (modified Simpson’s rule). MAM explained 82% of the stroke volume and 18% must, therefore, be explained by an inward motion of the outer left ventricular wall. A mean outer diameter shortening of about 3% (about 2 mm) was calculated.

    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-80940 (URN)10.1046/j.1365-2281.2001.00343.x (DOI)
    Available from: 2012-09-04 Created: 2012-09-04 Last updated: 2017-12-07Bibliographically approved
    2. The relation between mitral annulus motion and ejection fraction changes with age and heart size
    Open this publication in new window or tab >>The relation between mitral annulus motion and ejection fraction changes with age and heart size
    2000 (English)In: Clinical Physiology, ISSN 0144-5979, E-ISSN 1365-2281, Vol. 20, no 1, p. 38-43Article in journal (Refereed) Published
    Abstract [en]

    Mitral annulus motion (MAM) has recently been introduced as an index of left ventricular function. Several echocardiographic studies have shown good agreement between ejection fraction (EF) and MAM × 5, where MAM is the total mitral annulus motion, measured in mm, and EF is expressed as a percentage. This means that if MAM is used for estimation of left ventricular function, the conversion factor 5 is used, if the function is expressed as EF. In these studies, the mean age of the patients was over 60 years. The present study, including 102 patients, shows that in patients aged 20–40 years, the conversion factor is about 4·3, in patients aged 41–60 years it is about 4·6 and in patients aged 61–80 years it is about 5·0. It was also found that the ratio EF/MAM decreases with increasing height and left ventricular diameter, both variables closely connected to heart size. The results suggest that when MAM is used in assessment of left ventricular function, it is unwise to express the function in terms of EF. It is preferable to use MAM as a direct index of ventricular function, using reference values referred to aged and height. If the estimated function is expressed in terms of EF, different converting factors must be used depending on the age of the patients.

    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-26881 (URN)10.1046/j.1365-2281.2000.00221.x (DOI)11504 (Local ID)11504 (Archive number)11504 (OAI)
    Available from: 2009-10-08 Created: 2009-10-08 Last updated: 2017-12-13Bibliographically approved
    3. The relation between mitral annulus motion and ejection fraction: A nonlinear function
    Open this publication in new window or tab >>The relation between mitral annulus motion and ejection fraction: A nonlinear function
    2000 (English)In: Journal of the American Society of Echocardiography, ISSN 0894-7317, E-ISSN 1097-6795, Vol. 13, no 10, p. 896-901Article in journal (Refereed) Published
    Abstract [en]

    In previous studies of the relation between mitral annulus motion (MAM) and left ventricular ejection fraction (EF), a linear relationship has been suggested. In this meta-analysis of 434 patients, we show that the relation is nonlinear and that a linear regression model overestimates EF in the lower range of MAM. The relation is better described by an S function and is influenced by age and heart size.

    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-26880 (URN)10.1067/mje.2000.107253 (DOI)11503 (Local ID)11503 (Archive number)11503 (OAI)
    Available from: 2009-10-08 Created: 2009-10-08 Last updated: 2017-12-13Bibliographically approved
    4. The relation between mitral annulus motion and left ventricular ejection fraction in atrial fibrillation
    Open this publication in new window or tab >>The relation between mitral annulus motion and left ventricular ejection fraction in atrial fibrillation
    2000 (English)In: Clinical Physiology, ISSN 0144-5979, E-ISSN 1365-2281, Vol. 20, no 1, p. 44-49Article in journal (Refereed) Published
    Abstract [en]

    Mitral annulus motion (MAM) has recently been introduced as an index of left ventricular function. Previous studies have shown a good agreement between MAM (mm) × 5 and ejection fraction in middle-aged and elderly patients. These studies only included patients with sinus rhythm, while patients with atrial fibrillation were excluded. In the present study, MAM was reduced in patients with atrial fibrillation while ejection fraction (EF) did not differ from age-matched control patients with sinus rhythm. The ‘conversion factor’ (EF/MAM) was 7·2 in the group with atrial fibrillation and 5·1 in controls with sinus rhythm. This difference must be taken into account when MAM is used to estimate left ventricular function in patients with atrial fibrillation. Patients with atrial fibrillation had lower stroke volume and higher heart rate than patients with sinus rhythm. A decreased systolic long-axis shortening was found (P<0·005) compared to patients with sinus rhythm, but no difference in short-axis diameter shortening.

    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-26878 (URN)10.1046/j.1365-2281.2000.00222.x (DOI)11501 (Local ID)11501 (Archive number)11501 (OAI)
    Available from: 2009-10-08 Created: 2009-10-08 Last updated: 2017-12-13Bibliographically approved
    5. The relation between ejection fraction and mitral annulus motion before and after direct-current electrical cardioversion
    Open this publication in new window or tab >>The relation between ejection fraction and mitral annulus motion before and after direct-current electrical cardioversion
    2000 (English)In: Clinical Physiology, ISSN 0144-5979, E-ISSN 1365-2281, Vol. 20, no 3, p. 218-224Article in journal (Refereed) Published
    Abstract [en]

    Mitral annulus motion (MAM) and the relation between left ventricular ejection fraction (EF) and MAM has been shown to differ between patients with sinus rhythm and patients with atrial fibrillation. However, it has not been investigated how the relation between EF and MAM changes on direct-current (DC) electrical cardioversion to sinus rhythm. Therefore, 31 consecutive patients on the waiting list for DC electrical cardioversion were examined by echocardiography before DC electrical cardioversion, and those who maintained sinus rhythm (13 patients) were examined again 4–8 weeks after cardioversion. The conversion factor (CF) (ratio EF/MAM) decreased from 8·4 ± 1·7 before to 5·8 ± 0·8 SD after cardioversion (P<0·001). The EF increased slightly (P<0·05) but the MAM had a much greater increase (P<0·001), resulting in the decrease in CF. There was no significant difference in CF between patients after cardioversion and age- and gender-matched control patients with sinus rhythm, indicating that CF is normalized or almost normalized 4–8 weeks after cardioversion. This indicates that when MAM is used for investigation of the left ventricular function, and the function is expressed as EF, the same CF as in other patients with sinus rhythm can be used 4–8 weeks after DC electrical cardioversion.

    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-26879 (URN)10.1046/j.1365-2281.2000.00249.x (DOI)11502 (Local ID)11502 (Archive number)11502 (OAI)
    Available from: 2009-10-08 Created: 2009-10-08 Last updated: 2017-12-13Bibliographically approved
    6. Comparison between circumflex artery motion and mitral annulus motion
    Open this publication in new window or tab >>Comparison between circumflex artery motion and mitral annulus motion
    2001 (English)In: Scandinavian Cardiovascular Journal, ISSN 1401-7431, E-ISSN 1651-2006, Vol. 35, no 5, p. 318-325Article in journal (Refereed) Published
    Abstract [en]

    OBJECTIVE:

    To compare mitral annulus motion (MAM) with circumflex artery motion (CXM) and the motion amplitude at an endocardial site (representing MAM) with an epicardial site (representing CXM) at the most basal lateral part of the atrioventricular plane (AVP).

    DESIGN:

    MAM and CXM were obtained in 28 patients examined by echocardiography and coronary angiography. The motion amplitude epicardially and endocardially was recorded by echocardiography in 13 patients with normal ejection fraction (EF) (> or = 0.50) and in 13 patients with decreased EF (<0.50).

    RESULTS:

    CXM was higher than MAM in most patients with normal EF but lower than MAM in most patients with decreased EF. The motion amplitude epicardially was significantly higher (p < 0.001) than endocardially in patients with normal EF. while there was no significant difference in patients with decreased EF.

    CONCLUSION:

    CXM represents the motion of the epicardial part of the AVP and differs from MAM, which represents the endocardial part of the wall. This must be considered when CXM is used for assessment of left ventricular systolic function.

    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-26983 (URN)10.1080/140174301317116299 (DOI)11618 (Local ID)11618 (Archive number)11618 (OAI)
    Available from: 2009-10-08 Created: 2009-10-08 Last updated: 2017-12-13Bibliographically approved
  • 87.
    Engvall, Jan
    Linköping University, Department of Medicine and Care, Clinical Physiology. Linköping University, Faculty of Health Sciences.
    Aortic coarctation: Physiological and model studies1993Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    In 22 patients, referred for the assessment of significant native- or re-coarctation, the systolic cuff blood pressure difference between arm and ankle at rest and after three different subrnaximal exercise tests and one maximal test was compared with invasive blood pressure. Reference values of cuff blood pressure were obtained from 19 healthy adult volunteers. The cuff blood pressure difference at rest correlated closely with the invasive pressure difference and the degree of constriction as assessed by angiography. The cuff blood pressure difference one minute after the different exercise tests varied with the load. A pressure difference of 50 mm Hg one minute after submaximal treadmill exercise identified all individuals with an invasive pressure difference exceeding 50 mm Hg during supine exercise. After maximal exercise, a large difference was seen between arm and ankle in healthy subjects as well as in patients.

    Theoretical analysis and pressure measurements across a constriction in a physical flow model showed a relation between mean pressure and flow that could be expressed as a power function. Pressure recovery was 0-4 mm Hg in the model and of similar magnitude in patients.

    Simulations in a computer model of the central circulation showed that the downstream pressure and flow depended strongly on the properties of the collaterals. The length and diameter of the collateral influenced the transmission of pressure and flow, while collateral wall stiffness did not. The resistance and wall stiffness in the upstream circulation exerted an important influence upon the upstream pressure.

    Twenty patients, of whom 16 had undergone coarctation surgery, were investigated with bi-plane transoesophageal echocardiography (TEE) as well as with continuous wave Doppler from the suprasternal notch and magnetic resonance imaging (MRI). Seventeen healthy volunteers were investigated with MRI to obtain reference values. MRI in the axial plane showed the largest coarctation diameter, mean difference between methods 1.4±3.5 mm. Coarctation systolic velocity was 0.23 m/s higher with Doppler than with MRI. MRI peak flow ratio between the descending and ascending aorta showed a linear correlation with Doppler velocity and is proposed as a new measure of obstruction to flow.

    Twenty-four-hour non-invasive ambulatory blood pressure monitoring, performed on the 20 patients mentioned above, showed a significant negative correlation between the systolic blood pressure level and coarctation diameter, suggesting a remaining influence of the coarctation on the blood pressure even in patients who had undergone surgery.

  • 88.
    Engvall, Jan
    et al.
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV). Östergötlands Läns Landsting, Heart and Medicine Center, Department of Clinical Physiology in Linköping.
    Ask, Per
    Linköping University, Department of Biomedical Engineering, Physiological Measurements. Linköping University, The Institute of Technology.
    Loyd, Dan
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, The Institute of Technology.
    Wranne, Bengt
    Linköping University, Department of Medicine and Care, Clinical Physiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Clinical Physiology in Linköping.
    Coarctation of the aorta--a theoretical and experimental analysis of the effects of a centrally located arterial stenosis.1991In: Medical and Biological Engineering and Computing, ISSN 0140-0118, E-ISSN 1741-0444, Vol. 29, no 3, p. 291-296Article in journal (Refereed)
    Abstract [en]

    Aortic coarctation is a local constriction of the aorta that may severely affect haemodynamics. It is therefore important to quantify these effects. Using Bernoulli's equation and the momentum theorem, the pressure drop is described including the pressure recovery distal to the coarctation and the effects of collateral flow; both laminar and turbulent. Assuming the coarctation and collaterals to be stiff, a quadratic relationship between flow and pressure drop is expected for flow through the coarctation and for turbulent collateral flow. For laminar collateral flow, a linear relationship is expected. The coarctation flow was studied in a model consisting of a rigid tube with local constriction, connected to a flooded-level tank, containing a 36 per cent by weight solution of sucrose, with a viscosity equivalent to that of blood at body temperature. The pressure drop across the constriction showed a quadratic relationship to flow in agreement with theoretical expectations. Pressure recovery in this model was very slight (0-4 mm Hg). Nine patients with aortic coarctation were catheterised. Cardiac output and pressure drop across the coarctation were measured at rest and during supine cycle exercise at two different workloads. The relationship between mean pressure drop and cardiac output tended to be either 'parabolic' or, in some cases, approximately linear, suggesting that the flow situation in aortic coarctation can be quantified by expressions that either linearly or quadratically relate pressure and flow.

  • 89.
    Engvall, Jan
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Physiology. Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Karlsson, Matts
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Modelling and Simulation.
    Ask, Per
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Physiological Measurements.
    Loyd, Dan
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering, Applied Thermodynamics and Fluid Mechanics.
    Nylander, Eva
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Physiology. Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Wranne, Bengt
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Physiology. Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Importance of collateral vessels in aortic coarctation: Computer simulation at rest and exercise using transmission line elements1994In: Medical & Biological Engineering & Computing, ISSN 0140-0118, Vol. 32, p. 115-122Article in journal (Refereed)
  • 90.
    Engvall, Jan
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Physiology. Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Nyström, Fredrik
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Biomedicine and Surgery, Surgery. Östergötlands Läns Landsting, MKC-2, GE: endomed.
    Daytime ambulatory blood pressure correlates strongly with the echocardiographic diameter of aortic coarctation2001In: Scandinavian Cardiovascular Journal, ISSN 1401-7431, E-ISSN 1651-2006, Vol. 35, no 5, p. 335-339Article in journal (Refereed)
    Abstract [en]

    Objective.-To relate the echocardiographic aortic arch-diameter to ambulatory and clinic blood pressure (BP) in patients with aortic coarctation. Design.-Eighteen adult patients (50% men) were recruited from the coarctation registry of the Linkoping Heart Centre. Biplane-trans-oesophageal echocardiography (TEE) was performed with Acuson XP 128/10, ambulatory BP was recorded with Spacelab models 90202/90205. Results.-Systolic clinic and ambulatory BP levels were higher in patients than in the 36 controls (clinic BP: 146 ▒ 25 mmHg vs 119 ▒ 10 mmHg, p = 0.0009, ambulatory BP: 140 ▒ 18 mmHg vs 124 ▒ 11 mmHg, p = 0.009). The differences in diastolic BP levels were less obvious (clinic BP: 87 ▒ 16 mmHg vs 76 ▒ 8 mmHg, p = 0.02, ambulatory BP: 84 ▒ 13 mmHg vs 77 ▒ 9 mmHg, p = 0.052). Daytime ambulatory BP was more strongly related than clinic BP to the coarctation diameter (AD) (systolic BP r = -0.73, p = 0.0006 and r = -0.61, p = 0.007, respectively). In surgically corrected patients (n = 14) only the correlations between ambulatory systolic daytime (r = -0.61, p = 0.02) and night-time (r = -0.58, p = 0.03) BP to AD was statistically significant. Conclusion.-Ambulatory BP correlates strongly with aortic coarctation measured by TEE and would thus be the preferred technique for evaluating BP in this patient category.

  • 91.
    Escobar Kvitting, John-Peder
    Linköping University, Department of Medicine and Care, Clinical Physiology. Linköping University, Department of Medicine and Care, Center for Medical Image Science and Visualization. Linköping University, Faculty of Health Sciences.
    Quantification of cardiovascular flow and motion: aspects of regional myocardial function and flow patterns in the aortic root and the aorta2004Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Quantification of cardiovascular flow and motion is essential in the diagnosis, treatment and follow-up of cardiovascular disease. The accuracy and quantification of many imaging methods used in this field have important shortfalls, however, that result from limitations in spatial and temporal dimensions. Improvement in application of these methods requires an in-depth understanding of the technical and perceptual aspects that contribute to errors in their use.

    Visual assessment of echocardiographic images for asynchrony in regional myocardial motion during systolic contraction is an example of the need for better definition of limitations. The discernible delay in wall motion improved from 89 ms to 71 ms by allowing side-by-side comparison to normal motion. Clinically important delays are almost certainly missed with current "eyeballing" methods. Different and more quantitative approaches to this problem have been developed. Anatomic M-mode (AMM) assesses motion along an arbitrary line within a two-dimensional (2D) image, and was demonstrably robust in the clinical setting when used with second harmonic imaging at a depth less than 20 cm and with angle correction ofless than 60°. Doppler myocardial (DMI) imaging and strain rate imaging (SRI) were also shown to reliably demonstrate the effects of inotropic stimulation, total and severe ischemia on asynchrony in a closed chest pig model. Quantification of the changes induced by inotropy and total ischemia was possible with both methods, but the effects of stunning were not. Regional myocardial function and cardiovascular flow can also be assessed with time-resolved, three-directional, three-dimensional (3D) velocity data acquired using phase contrast magnetic resonance imaging (PC-MRI). This multidimensional data demonstrated longitudinal velocity gradients along all four walls of the left ventricle, with miuirnal apical longitudinal motion. The 3D velocity vector from single points in the ventricular wall shows that the motion over the cardiac cycle is complex in all dimensions. The flow patterns in the aortic root were also studied using time-resolved 3D PC-MRI in normal volunteers and patients who had undergone aortic-valve sparing surgery using straight Dacron grafts. In normals, vortices appeared in the sinuses of Valsalva in late systole, increased in size with the deceleration of aortic outflow and moved together as the valve closed in early diastole. These normal flow structures have never before been demonstrated in three dimensions in man. In the postoperative patients, lacking both sinuses and sinotubular junction, vortices were not observed.

    Many imaging methods can be improved by a critical definition of the limits oftheir reliability. This can prompt the modifications and new methods which allow us to move beyond the original shortcomings and contribute new knowledge regarding the pathophysiology of cardiovascular disease.

    List of papers
    1. How accurate is visual assessment of synchronicity in myocardial motion? An in vitro study with computer-simulated regional delay in myocardial motion: clinical implications for rest and stress echocardiography studies
    Open this publication in new window or tab >>How accurate is visual assessment of synchronicity in myocardial motion? An in vitro study with computer-simulated regional delay in myocardial motion: clinical implications for rest and stress echocardiography studies
    1999 (English)In: Journal of the American Society of Echocardiography, ISSN 0894-7317, E-ISSN 1097-6795, Vol. 12, no 9, p. 698-705Article in journal (Refereed) Published
    Abstract [en]

    Asynchronicity in echocardiographic images is normally assessed visually. No prior quantitative studies have determined the limitations of this approach. To quantify visual recognition of myocardial asynchronicity in echocardiographic images, computer-simulated delay phantom loops were generated from a 3.3 MHz digital image data from a normal left ventricular short-axis heart cycle acquired at 55 frames per second. Six expert observers visually assessed 30 abnormal and 3 normal loops with differing computer-induced delay patterns on 3 occasions and in this optimally simulated environment could recognize only single delays of 89 ms or more. This was improved to 71 ms or more by use of side-by-side (normal versus abnormal) comparative review. Thus visual assessment of clinically important regional delay in rest or stress echo images is limited.

    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-26982 (URN)10.1016/S0894-7317(99)70019-2 (DOI)11617 (Local ID)11617 (Archive number)11617 (OAI)
    Available from: 2009-10-08 Created: 2009-10-08 Last updated: 2017-12-13
    2. Anatomic M-mode echocardiography: a new approach to assess regional myocardial function - A comparative in vivo and in vitro study of both fundamental and second harmonic imaging modes
    Open this publication in new window or tab >>Anatomic M-mode echocardiography: a new approach to assess regional myocardial function - A comparative in vivo and in vitro study of both fundamental and second harmonic imaging modes
    Show others...
    1999 (English)In: Journal of the American Society of Echocardiography, ISSN 0894-7317, E-ISSN 1097-6795, Vol. 12, no 5, p. 300-307Article in journal (Refereed) Published
    Abstract [en]

    Objective: To evaluate the accuracy of anatomic M-mode echocardiography (AMM).

    Methods: Eight phantoms were rotated on a device at different insonation depths (IDs) in a water beaker. They were insonated with different transducer frequencies in fundamental imaging (FI) and second harmonic imaging (SHI), and the diameters were assessed with conventional M-mode echocardiography (CMM) and AMM with the applied angle correction (AC) after rotation. In addition, left ventricular wall dimensions were measured with CMM and AMM in FI and SHI in 10 volunteers.

    Results: AC had the greatest effect on the measurement error in AMM followed by ID (AC: R2 = 0.295, ID: R2 = 0.268; P < .0001). SHI improved the accuracy, and a difference no longer existed between CMM and AMM with an AC up to 60 degrees. In vivo the limit of agreement between AMM and CMM was -1.7 to +1.8 mm in SHI.

    Conclusion: Within its limitations (AC < 60 degrees; ID < 20 cm), AMM could be a robust tool in clinical practice.

    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-26981 (URN)10.1016/S0894-7317(99)70050-7 (DOI)11616 (Local ID)11616 (Archive number)11616 (OAI)
    Available from: 2009-10-08 Created: 2009-10-08 Last updated: 2017-12-13
    3. Regional asynchrony in acute ischemia and stunning: an experimental myocardial velocity and strain rate imaging study
    Open this publication in new window or tab >>Regional asynchrony in acute ischemia and stunning: an experimental myocardial velocity and strain rate imaging study
    Show others...
    (English)Manuscript (preprint) (Other academic)
    Abstract [en]

    Objective: To quantify motion and deformation asynchrony using Doppler myocardial imaging (DMI) during acute total ischemia, and stunning of the posterior left ventricular wall (PW) in comparison with the interventricular septum (IVS).

    Methods: Ischemia of the PW was induced in closed-chest pigs using an angioplasty balloon positioned in the circumflex coronary artery. Animals were divided into three groups: normal controls (Group I - n = 6), total ischemia (Group II - n = 8), and stunning (Group III - n = 6) induced by coronary occlusion with distal coronary perfusion maintained via a perfusion catheter coupled to a roller pump (Group III). In addition, a 2-step dobutamine challenge (5 and 10 µg.kg-1 .min-1) was performed in groups I and III. Doppler myocardial velocity and strain rate cineloops were acquired from a parasternal short axis view.

    Results: The pre-ejection time (T1) and the duration of regional mechanical systole (SYS) became shorter with inotropic stimulation. During total ischemia T1 was prolonged and SYS shortened significantly compared to baseline values [62 ± 14 vs. 55 ± 13 ms (P < 0.05)], [164 ± 13 vs. 240 ± 27 ms (P < 0.001)], respectively. The fraction T1/SYS was accordingly higher. No changes were observed for the contra lateral non-ischemic wall. In group III, the post-ischemic myocardium had a similar response as non-ischemic myocardium to the dobutamine challenge.

    Conclusion: Consistent changes in local pre-ejection time and regional mechanical systole are induced by intropic stimulation and by total ischemia. However, the response to intropic stimulation did not differ between normal and stunned myocardium.

    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-84958 (URN)
    Available from: 2012-10-29 Created: 2012-10-29 Last updated: 2012-10-29
    4. Three-directional myocardial motion assessed using 3D phase contrast MRI
    Open this publication in new window or tab >>Three-directional myocardial motion assessed using 3D phase contrast MRI
    Show others...
    2004 (English)In: Journal of Cardiovascular Magnetic Resonance, ISSN 1097-6647, E-ISSN 1532-429X, Vol. 6, no 3, p. 627-636Article in journal (Refereed) Published
    Abstract [en]

    Regional myocardial function is a complex entity consisting of motion in three dimensions (3D). Besides magnetic resonance imaging (MRI), no other noninvasive technique can give a true 3D description of cardiac motion. Using a time‐resolved 3D phase contrast technique, three‐dimensional image volumes containing myocardial velocity data in six normal volunteers were acquired. Coordinates and velocity information were extracted from nine points placed in different myocardial segments in the left ventricle (LV), and decomposed into longitudinal (VL), radial (VR), and circumferential (VC) velocity components. Our findings confirm a longitudinal apex‐to‐base gradient for the LV, with only a small motion of the apex. The mean velocity for VL for all the basal segments was higher compared to the midsegments during systole [3.5 ± 1.2 vs. 2.5 ± 1.7 cm/s (p < 0.01)], early filling [− 6.9 ± 1.8 vs. − 4.9 ± 1.8 cm/s (p < 0.001)], and during atrial contraction [− 2.2 ± 1.4 vs. − 1.6 ± 1.3 cm/s (p < 0.05)]. A similar pattern was observed when comparing velocities from the midsegments to the apex. Radial velocity was higher during early filling in the midportion of the lateral [− 4.9 ± 2.7 vs. − 3.2 ± 1.6 cm/s (p < 0.05)] wall compared to the basal segments, no difference was observed for the septal [− 2.0 ± 1.5 vs. − 0.3 ± 2.5 cm/s (p = 0.15)], anterior [− 5.8 ± 3.3 vs. − 4.0 ± 1.7 cm/s (p = 0.17)], and posterior [− 2.3 ± 2.1 vs. − 2.5 ± 1.0 cm/s (p = 0.78)] walls. When observing the myocardial velocity in a single point and visualizing the movement of the main direction of the velocities in this point as vectors in velocity vector plots like planes, it is clear that myocardial movement is by no means one dimensional. In conclusion, our time‐resolved 3D, phase contrast MRI technique makes it feasible to extract myocardial velocities from anywhere in the myocardium, including all three velocity components without the need for positioning any slices at the time of acquisition.

    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-24306 (URN)10.1081/JCMR-120038692 (DOI)3929 (Local ID)3929 (Archive number)3929 (OAI)
    Available from: 2009-10-07 Created: 2009-10-07 Last updated: 2017-12-13
    5. Flow patterns in the aortic root and the aorta studied with time-resolved, 3-dimensional, phase-contrast magnetic resonance imaging: implications for aortic valve–sparing surgery
    Open this publication in new window or tab >>Flow patterns in the aortic root and the aorta studied with time-resolved, 3-dimensional, phase-contrast magnetic resonance imaging: implications for aortic valve–sparing surgery
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    2004 (English)In: Journal of Thoracic and Cardiovascular Surgery, ISSN 0022-5223, E-ISSN 1097-685X, Vol. 127, no 6, p. 1602-1607Article in journal (Refereed) Published
    Abstract [en]

    Objective

    Sparing the aortic valve has become a surgical option for patients who require repair of aortic root ectasia and have normal valve leaflets. Surgical approaches to valve sparing differ with regard to preservation of the native sinuses of Valsalva. The role of the sinuses and the importance of maintaining them remain controversial.

    Methods

    By using a time-resolved, 3-dimensional, phase-contrast magnetic resonance imaging technique, aortic root and aortic blood velocity data were acquired from 2 patients with Marfan syndrome 6 months after aortic valve–sparing surgery with straight Dacron grafts and contrasted with data from 6 normal volunteers.

    Results

    In normal aortas vortical blood flow became apparent in the individual sinuses after peak systole. The vortices filled the available space behind the valve leaflets and persisted until diastole, expanding and moving inward during aortic valve closure. In contrast, no vortices were observed in the postoperative patients with Marfan syndrome with negligible sinuses.

    Conclusions

    Changes in supravalvular flow accompany loss of sinus architecture. Whether the presence, size, and velocity of supravalvular vortices affects the function or durability of the preserved aortic valve remains to be studied.

    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-24305 (URN)10.1016/j.jtcvs.2003.10.042 (DOI)3927 (Local ID)3927 (Archive number)3927 (OAI)
    Available from: 2009-10-07 Created: 2009-10-07 Last updated: 2017-12-13
  • 92.
    Escobar Kvitting, John-Peder
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Physiology. Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Brandt, Einar
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Physiology. Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Wigström, Lars
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Physiology. Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Engvall, Jan
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Physiology. Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Visualization of flow in the aorta using time-resolved 3D phase contrast MRI2001In: Proc. Intl. Soc. Mag. Reson. Med.,2001, 2001, p. 378-378Conference paper (Refereed)
  • 93.
    Escobar Kvitting, John-Peder
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Physiology. Östergötlands Läns Landsting, Centre of Surgery and Oncology, Department of Surgery in Östergötland.
    Dyverfeldt, Petter
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Health Sciences, Clinical Physiology . Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Boano, G
    Sigfridsson, Andreas
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Health Sciences, Clinical Physiology . Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Engvall, Jan
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Health Sciences, Clinical Physiology . Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Bolger, Ann F
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Health Sciences, Clinical Physiology . Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Ebbers, Tino
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Health Sciences, Clinical Physiology . Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Multidimensional Turbulence Mapping in Mitral Insufficiency2008In: Soc Cardiovascular Magn Reson. 11th Scientific Sessions,2008, 2008Conference paper (Other academic)
  • 94.
    Escobar Kvitting, John-Peder
    et al.
    Linköping University, Department of Medicine and Care, Clinical Physiology. Linköping University, Department of Medicine and Care, Center for Medical Image Science and Visualization. Linköping University, Faculty of Health Sciences.
    Ebbers, Tino
    Linköping University, Department of Medicine and Care, Clinical Physiology. Linköping University, Department of Medicine and Care, Center for Medical Image Science and Visualization. Linköping University, Faculty of Health Sciences.
    Engvall, Jan
    Linköping University, Department of Medicine and Care, Clinical Physiology. Linköping University, Department of Medicine and Care, Center for Medical Image Science and Visualization. Linköping University, Faculty of Health Sciences.
    Sutherland, George R.
    Department of Cardiology, University Hospital Gasthuisberg, Leuven, Belgium.
    Wranne, Bengt
    Linköping University, Department of Medicine and Care, Clinical Physiology. Linköping University, Department of Medicine and Care, Center for Medical Image Science and Visualization. Linköping University, Faculty of Health Sciences.
    Wigström, Lars
    Linköping University, Department of Medicine and Care, Clinical Physiology. Linköping University, Department of Medicine and Care, Center for Medical Image Science and Visualization. Linköping University, Faculty of Health Sciences.
    Three-directional myocardial motion assessed using 3D phase contrast MRI2004In: Journal of Cardiovascular Magnetic Resonance, ISSN 1097-6647, E-ISSN 1532-429X, Vol. 6, no 3, p. 627-636Article in journal (Refereed)
    Abstract [en]

    Regional myocardial function is a complex entity consisting of motion in three dimensions (3D). Besides magnetic resonance imaging (MRI), no other noninvasive technique can give a true 3D description of cardiac motion. Using a time‐resolved 3D phase contrast technique, three‐dimensional image volumes containing myocardial velocity data in six normal volunteers were acquired. Coordinates and velocity information were extracted from nine points placed in different myocardial segments in the left ventricle (LV), and decomposed into longitudinal (VL), radial (VR), and circumferential (VC) velocity components. Our findings confirm a longitudinal apex‐to‐base gradient for the LV, with only a small motion of the apex. The mean velocity for VL for all the basal segments was higher compared to the midsegments during systole [3.5 ± 1.2 vs. 2.5 ± 1.7 cm/s (p < 0.01)], early filling [− 6.9 ± 1.8 vs. − 4.9 ± 1.8 cm/s (p < 0.001)], and during atrial contraction [− 2.2 ± 1.4 vs. − 1.6 ± 1.3 cm/s (p < 0.05)]. A similar pattern was observed when comparing velocities from the midsegments to the apex. Radial velocity was higher during early filling in the midportion of the lateral [− 4.9 ± 2.7 vs. − 3.2 ± 1.6 cm/s (p < 0.05)] wall compared to the basal segments, no difference was observed for the septal [− 2.0 ± 1.5 vs. − 0.3 ± 2.5 cm/s (p = 0.15)], anterior [− 5.8 ± 3.3 vs. − 4.0 ± 1.7 cm/s (p = 0.17)], and posterior [− 2.3 ± 2.1 vs. − 2.5 ± 1.0 cm/s (p = 0.78)] walls. When observing the myocardial velocity in a single point and visualizing the movement of the main direction of the velocities in this point as vectors in velocity vector plots like planes, it is clear that myocardial movement is by no means one dimensional. In conclusion, our time‐resolved 3D, phase contrast MRI technique makes it feasible to extract myocardial velocities from anywhere in the myocardium, including all three velocity components without the need for positioning any slices at the time of acquisition.

  • 95.
    Escobar Kvitting, John-Peder
    et al.
    Linköping University, Department of Medicine and Care, Clinical Physiology. Linköping University, Faculty of Health Sciences.
    Ebbers, Tino
    Linköping University, Department of Medicine and Care, Clinical Physiology. Linköping University, Faculty of Health Sciences.
    Wigström, Lars
    Linköping University, Department of Medicine and Care, Clinical Physiology. Linköping University, Faculty of Health Sciences.
    Engvall, Jan
    Linköping University, Department of Medicine and Care, Clinical Physiology. Linköping University, Faculty of Health Sciences.
    Olin, Christian L.
    Linköping University, Department of Medicine and Care, Thoracic Surgery. Linköping University, Faculty of Health Sciences.
    Bolger, Ann F.
    Department of Medicine, University of California San Francisco, San Francisco, Calif, USA.
    Flow patterns in the aortic root and the aorta studied with time-resolved, 3-dimensional, phase-contrast magnetic resonance imaging: implications for aortic valve–sparing surgery2004In: Journal of Thoracic and Cardiovascular Surgery, ISSN 0022-5223, E-ISSN 1097-685X, Vol. 127, no 6, p. 1602-1607Article in journal (Refereed)
    Abstract [en]

    Objective

    Sparing the aortic valve has become a surgical option for patients who require repair of aortic root ectasia and have normal valve leaflets. Surgical approaches to valve sparing differ with regard to preservation of the native sinuses of Valsalva. The role of the sinuses and the importance of maintaining them remain controversial.

    Methods

    By using a time-resolved, 3-dimensional, phase-contrast magnetic resonance imaging technique, aortic root and aortic blood velocity data were acquired from 2 patients with Marfan syndrome 6 months after aortic valve–sparing surgery with straight Dacron grafts and contrasted with data from 6 normal volunteers.

    Results

    In normal aortas vortical blood flow became apparent in the individual sinuses after peak systole. The vortices filled the available space behind the valve leaflets and persisted until diastole, expanding and moving inward during aortic valve closure. In contrast, no vortices were observed in the postoperative patients with Marfan syndrome with negligible sinuses.

    Conclusions

    Changes in supravalvular flow accompany loss of sinus architecture. Whether the presence, size, and velocity of supravalvular vortices affects the function or durability of the preserved aortic valve remains to be studied.

  • 96.
    Escobar Kvitting, John-Peder
    et al.
    Linköping University, Department of Medicine and Care, Clinical Physiology. Linköping University, Faculty of Health Sciences.
    Jamal, Fadi
    Department of Cardiology, University Hospital Gasthuisberg, Leuven, Belgium.
    Weidemann, Frank
    Department of Cardiology, University Hospital Gasthuisberg, Leuven, Belgium.
    Kukulski, Tomasz
    Department of Cardiology, University Hospital Gasthuisberg, Leuven, Belgium.
    Strotmann, Jörg M.
    Department of Cardiology, University Hospital of Würzburg, Germany.
    Wranne, Bengt
    Linköping University, Department of Medicine and Care, Clinical Physiology. Linköping University, Faculty of Health Sciences.
    Sutherland, George R.
    Department of Cardiology, University Hospital Gasthuisberg, Leuven, Belgium.
    Regional asynchrony in acute ischemia and stunning: an experimental myocardial velocity and strain rate imaging studyManuscript (preprint) (Other academic)
    Abstract [en]

    Objective: To quantify motion and deformation asynchrony using Doppler myocardial imaging (DMI) during acute total ischemia, and stunning of the posterior left ventricular wall (PW) in comparison with the interventricular septum (IVS).

    Methods: Ischemia of the PW was induced in closed-chest pigs using an angioplasty balloon positioned in the circumflex coronary artery. Animals were divided into three groups: normal controls (Group I - n = 6), total ischemia (Group II - n = 8), and stunning (Group III - n = 6) induced by coronary occlusion with distal coronary perfusion maintained via a perfusion catheter coupled to a roller pump (Group III). In addition, a 2-step dobutamine challenge (5 and 10 µg.kg-1 .min-1) was performed in groups I and III. Doppler myocardial velocity and strain rate cineloops were acquired from a parasternal short axis view.

    Results: The pre-ejection time (T1) and the duration of regional mechanical systole (SYS) became shorter with inotropic stimulation. During total ischemia T1 was prolonged and SYS shortened significantly compared to baseline values [62 ± 14 vs. 55 ± 13 ms (P < 0.05)], [164 ± 13 vs. 240 ± 27 ms (P < 0.001)], respectively. The fraction T1/SYS was accordingly higher. No changes were observed for the contra lateral non-ischemic wall. In group III, the post-ischemic myocardium had a similar response as non-ischemic myocardium to the dobutamine challenge.

    Conclusion: Consistent changes in local pre-ejection time and regional mechanical systole are induced by intropic stimulation and by total ischemia. However, the response to intropic stimulation did not differ between normal and stunned myocardium.

  • 97.
    Escobar Kvitting, John-Peder
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Physiology. Östergötlands Läns Landsting, Centre of Surgery and Oncology, Department of Surgery in Östergötland.
    Sandström, Per
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Biomedicine and Surgery, Division of surgery. Östergötlands Läns Landsting, Centre of Surgery and Oncology, Department of Surgery in Östergötland.
    Thorelius, Lars
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Medical Radiology.
    Kullman, Eric
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Biomedicine and Surgery, Division of surgery. Östergötlands Läns Landsting, Centre of Surgery and Oncology, Department of Surgery in Östergötland.
    Borch, Kurt
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Biomedicine and Surgery, Division of surgery. Östergötlands Läns Landsting, Centre of Surgery and Oncology, Department of Surgery in Östergötland.
    Svanvik, Joar
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Biomedicine and Surgery, Division of surgery. Östergötlands Läns Landsting, Centre of Surgery and Oncology, Department of Surgery in Östergötland.
    Radiofrequency ablation of a liver metastasis complicated by extensive liver necrosis and sepsis caused by gas gangrene2006In: Surgery, ISSN 0039-6060, E-ISSN 1532-7361, Vol. 139, no 1, p. 123-125Article in journal (Refereed)
    Abstract [en]

    [No abstract available]

  • 98.
    Escobar Kvitting, John-Peder
    et al.
    Linköping University, Department of Medicine and Care, Clinical Physiology. Linköping University, Faculty of Health Sciences.
    Wigström, Lars
    Linköping University, Department of Medicine and Care, Clinical Physiology. Linköping University, Faculty of Health Sciences.
    Strotmann, Jörg M.
    Sutherland, George
    How accurate is visual assessment of synchronicity in myocardial motion? An in vitro study with computer-simulated regional delay in myocardial motion: clinical implications for rest and stress echocardiography studies1999In: Journal of the American Society of Echocardiography, ISSN 0894-7317, E-ISSN 1097-6795, Vol. 12, no 9, p. 698-705Article in journal (Refereed)
    Abstract [en]

    Asynchronicity in echocardiographic images is normally assessed visually. No prior quantitative studies have determined the limitations of this approach. To quantify visual recognition of myocardial asynchronicity in echocardiographic images, computer-simulated delay phantom loops were generated from a 3.3 MHz digital image data from a normal left ventricular short-axis heart cycle acquired at 55 frames per second. Six expert observers visually assessed 30 abnormal and 3 normal loops with differing computer-induced delay patterns on 3 occasions and in this optimally simulated environment could recognize only single delays of 89 ms or more. This was improved to 71 ms or more by use of side-by-side (normal versus abnormal) comparative review. Thus visual assessment of clinically important regional delay in rest or stress echo images is limited.

  • 99. Fogel, WA
    et al.
    Andrzejewski, W
    Sasiak, K
    Granerus, Göran
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Physiology. Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Lönnqvist, Birgitta
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Physiology.
    Tuomisto, L
    Tarhanen, J
    Can urinary N-tele methylimidazoleacetic acid (t-MeImAA) serve as a marker of histaminergic activity in hepatic encephalopathy (HE)?2002In: Inflammation Research, ISSN 1023-3830, E-ISSN 1420-908X, Vol. 51, no SUPPL.1Article in journal (Refereed)
  • 100. Forsum, E
    et al.
    Löf, M
    Boström, K
    Janerot-Sjöberg, Birgitta
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Physiology. Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Changes in basal metabolic rate during pregnancy in relation to body size and composition, circulatory changes and fetal growth.2001In: Int. Congress on Nutrition, Wien 2001,2001, 2001, p. 100-100Conference paper (Refereed)
123456 51 - 100 of 294
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