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  • 1. Order onlineBuy this publication >>
    Carlén, Anna
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart and Medicine Center, Department of Clinical Physiology in Linköping.
    Exercise Testing in Firefighters: Work Capacity and Cardiovascular Risk Assessment in a Low-Risk Population2019Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Background. Firefighting is one of the most physically demanding occupations and it requires a high cardiorespiratory fitness level.

    Pre-duty medical evaluation of firefighters includes fitness testing and assessment of cardiac health to ensure that firefighters meet the minimum physical fitness standard and to ensure that they are not at increased risk of cardiac events. The medical evaluation methods for Swedish firefighters are regulated by the Swedish Work Environment Authority and include a 6 min constant workload treadmill (TM) test for fitness evaluation in which the firefighter wears full smoke diving equipment and a maximal effort exercise electrocardiography test (ExECG) at cycle ergometer (CE) for assessment of cardiac health. Previously, fitness was also evaluated by cycle ergometry.

    The standard parameter for evaluation of ischaemic heart disease (IHD) is exercise-induced ST depression. In general, exercise testing of asymptomatic low-risk individuals is discouraged due to low sensitivity and specificity for IHD, generating both false-positive and false-negative test results. Heart rate (HR) adjustment of the ST-segment response has been shown to be superior to simple ST depression to evaluate cardiac ischaemia in some populations, but has not been extensively evaluated in an occupational setting.

    Methods. We retrospectively analysed a cohort of 774 firefighters who were asymptomatic at the time of the testing.

    In paper I, test approval, HR response, and calculated oxygen uptake from TM tests and CE tests for 424 firefighters (44±10 years) were compared.

    Paper II methodologically described the process for data extraction, processing, and calculation of ExECG data from a clinical database. Procedures for noise assessment, error checking, and computerized calculation of ST/HR parameters were described.

    In paper III, ExECG and medical records of 521 male firefighters (44±10 years) were studied. During 8.4 ± 2.1 years of follow-up, IHD was verified angiographically in 12 subjects. The predictive value of HR-adjusted ST variables (ST/HR index, ST/HR slope, and ST/HR loop) for IHD was evaluated.

    In paper IV, subjects with objectively verified IHD were excluded and factors associated with exercise-induced nonischaemic ST depression were studied in the remaining 509 males (46±11 years).

     

    Results. The firefighters had an average maximal exercise capacity of 281 ± 36 W (range 186-467 W) achieved by incremental CE exercise. To enable comparison, the maximal workload was converted to the workload sustainable for 6 min. It was more common to pass the 6 min TM fitness test but to fail the supposedly equivalent CE test rather than vice versa.

    Twenty percent of the firefighters developed an ST depression of ≥o.1 mV in at least one lead during exercise and half of the firefighters had a horizontal or downsloping ST depression. While an abnormal ST response associated with an increased risk for IHD only in V4, both an abnormal ST/HR index and an abnormal ST/HR slope associated with IHD in three leads each. Clockwise rotation of the ST/HR loop was infrequent in all precordial leads (1%), but it associated with an increased risk for IHD.

    In the subgroup without evidence of coronary artery disease, age and the HR response associated with ST depression, whereas hypertension, hyperlipidaemia, diabetes, blood pressure response, and exercise capacity did not.

     

    Conclusions. Even though the calculated oxygen uptake was higher for the TM test than for the supposedly equivalent CE test, the higher treadmill approval rate may indicate that the fitness requirement for Swedish firefighters has been lowered by changing the test modality.

    Exercise-induced ST depression was common in asymptomatic physically active men, although there were only a few cases of IHD during follow-up. If performing ExECG in asymptomatic, low-risk populations, ST/HR analysis could be given more importance. However, the limited clinical value of ExECG in low-risk populations was emphasised and needs to be reconsidered.

    In asymptomatic, physically active men without coronary artery disease, false-positive ST depressions can be partially explained by HR variables rather than by common cardiovascular risk factors and blood pressure response to exercise.

    List of papers
    1. Loaded treadmill walking and cycle ergometry to assess work capacity: a retrospective comparison in 424 firefighters.
    Open this publication in new window or tab >>Loaded treadmill walking and cycle ergometry to assess work capacity: a retrospective comparison in 424 firefighters.
    2017 (English)In: Clinical Physiology and Functional Imaging, ISSN 1475-0961, E-ISSN 1475-097X, Vol. 37, no 1, p. 37-44Article in journal (Refereed) Published
    Abstract [en]

    The fitness of firefighters is regularly evaluated using exercise tests. We aimed to compare, with respect to age and body composition, two test modalities for the assessment work capacity. A total of 424 Swedish firefighters with cycle ergometer (CE) and treadmill (TM) tests available from Jan 2004 to Dec 2010 were included. We compared results from CE (6 min at 200 W, 250 W or incremental ramp exercise) with TM (6 min at 8° inclination, 4·5 km h(-1) or faster, wearing 24-kg protective equipment). Oxygen requirements were estimated by prediction equations. It was more common to pass the TM test and fail the supposedly equivalent CE test (20%), than vice versa (0·5%), P<0·001. Low age and tall stature were significant predictors of passing both CE and TM tests (P<0·05), while low body mass predicted accomplishment of TM test only (P = 0·006). Firefighters who passed the TM but failed the supposedly equivalent CE test within 12 months had significantly lower body mass, lower BMI, lower BSA and shorter stature than did those who passed both tests. Calculated oxygen uptake was higher in TM tests compared with corresponding CE tests (P<0·001). Body constitution affected approval differently depending on the test modality. A higher approval rate in TM testing suggests lower cardiorespiratory requirements compared with CE testing, even though estimated oxygen uptake was higher during TM testing. The relevance of our findings in relation to the occupational demands needs reconsidering.

    National Category
    Sport and Fitness Sciences
    Identifiers
    urn:nbn:se:liu:diva-120004 (URN)10.1111/cpf.12265 (DOI)000390688200006 ()26096157 (PubMedID)
    Note

    Funding agencies: ALF grants; County Council of Ostergotland, Sweden; Olav Axelssons memorial fund

    Available from: 2015-07-02 Created: 2015-07-02 Last updated: 2019-08-21
    2. ST/HR variables in firefighter exercise ECG: relation to ischemic heart disease
    Open this publication in new window or tab >>ST/HR variables in firefighter exercise ECG: relation to ischemic heart disease
    2019 (English)In: Physiological Reports, E-ISSN 2051-817X, Vol. 7, no 2, article id e13968Article in journal (Refereed) Published
    Abstract [en]

    Exercise electrocardiography (ExECG) is regularly performed by Swedish firefighters by law. Heart rate-corrected analysis of ST segment variables (ST/HR) has shown improved prediction of ischemic heart disease (IHD) compared to ST depression alone. This has not previously been extensively studied in asymptomatic persons with a low probability of IHD. We therefore evaluated the predictive performance of ST/HR analysis in firefighter ExECG. ExECG was studied in 521 male firefighters. During 8.4 ± 2.1 years, 2.3% (n = 12) were verified with IHD by catheterization or myocardial scintigraphy (age 51.5 ± 5.5 years) and were compared with firefighters without imaging proof of IHD (44.2 ± 10.1 years). The predictive value of ST depression, ST/HR index, ST/HR slope, and area and rotation of the ST/HR loop was calculated as age-adjusted odds ratios (OR), in 10 ECG leads. Predictive accuracy was analyzed with receiver operating characteristics (ROC) analysis. ST/HR index ≤-1.6 μV/bpm and ST/HR slope ≤-2.4 μV/bpm were associated with increased IHD risk in three individual leads (all OR > 1.0, P < 0.05). ST/HR loop area lower than the fifth percentile of non-IHD subjects indicated IHD risk in V4, V5, aVF, II, and -aVR (P < 0.05). ST depression ≤-0.1 mV was associated with IHD only in V4 (OR, 9.6, CI, 2.3-40.0). ROC analysis of each of these variables yielded areas under the curve of 0.72 or lower for all variables and leads. Clockwise-rotated ST/HR loops was associated with increased risk in most leads compared to counterclockwise rotation. The limited clinical value of ExECG in low-risk populations was emphasized, but if performed, ST/HR analysis should probably be given more importance.

    Place, publisher, year, edition, pages
    John Wiley & Sons, 2019
    Keywords
    Electrocardiography, ST depression, ST/HR variables, low risk
    National Category
    Cardiac and Cardiovascular Systems
    Identifiers
    urn:nbn:se:liu:diva-159752 (URN)10.14814/phy2.13968 (DOI)000457188800007 ()30688031 (PubMedID)2-s2.0-85060598157 (Scopus ID)
    Available from: 2019-08-20 Created: 2019-08-20 Last updated: 2020-03-25Bibliographically approved
    3. Exercise-induced ST depression in an asymptomatic population without coronary artery disease
    Open this publication in new window or tab >>Exercise-induced ST depression in an asymptomatic population without coronary artery disease
    2019 (English)In: Scandinavian Cardiovascular Journal, ISSN 1401-7431, E-ISSN 1651-2006, Vol. 53, no 4, p. 206-212Article in journal (Refereed) Published
    Abstract [en]

    Objectives. Exercise electrocardiogram (ExECG) in low risk populations frequently generates false positive ST depression. We aimed to characterize factors that are associated with exercise-induced ST depression in asymptomatic men without coronary artery disease. Design. Cycle ergometer exercise tests from 509 male firefighters without imaging proof of significant coronary artery disease were analysed. Analysed test data included heart rate at rest before exercise, and workload, blood pressure, heart rate, ST depression and ST segment slope at peak exercise. ST depression of amp;gt;0.1 mV was considered significant (STdep). With a mean follow-up of 6.1 +/- 1.7 years, medical records were reviewed for cardiovascular diagnoses, hyperlipidemia and diabetes. Logistic regression analysis was used for risk assessment. Results. In total, 22% had STdep in amp;gt;= 1 lead. Subjects with STdep were older than those with normal ExECG (p amp;lt; .001). Downsloping STdep was more common in extremity leads (9%) than in precordial leads (2%). STdep was categorized according to location (precordial/extremity) and slope direction into eight categories. Larger age-adjusted heart rate increase predicted STdep in seven categories (p amp;lt; .05). Age-adjusted peak heart rate correlated with STdep in five categories, predominantly where the ST slope was positive. Peak blood pressure and exercise capacity were both associated with STdep in few categories. We found no association between STdep and hypertension, hyperlipidemia or diabetes (all p amp;gt; .05). Conclusions. In asymptomatic men with a physically demanding occupation and no coronary artery disease, both age and heart rate response were associated with ST depression, whereas common cardiovascular risk factors, blood pressure response and exercise capacity were not.

    Place, publisher, year, edition, pages
    Taylor & Francis, 2019
    Keywords
    Stress test; false positive; electrocardiography; heart rate; ST segment deviation; firefighters; low risk
    National Category
    Cardiac and Cardiovascular Systems
    Identifiers
    urn:nbn:se:liu:diva-158872 (URN)10.1080/14017431.2019.1626021 (DOI)000472278700001 ()31144537 (PubMedID)
    Note

    Funding Agencies|County Council of Ostergotland, Sweden [LIO-711261]; ALF grant [700731]

    Available from: 2019-07-15 Created: 2019-07-15 Last updated: 2019-11-07
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  • 2.
    Carlén, Anna
    et al.
    Linköping University, Department of Health, Medicine and Caring Sciences, Division of Diagnostics and Specialist Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart Center, Department of Clinical Physiology in Linköping.
    Eklund, Gustaf
    Linköping University, Department of Health, Medicine and Caring Sciences. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart Center, Department of Clinical Physiology in Linköping.
    Andersson, August
    Linköping University, Department of Health, Medicine and Caring Sciences. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart Center, Department of Clinical Physiology in Linköping.
    Carlhäll, Carljohan
    Linköping University, Department of Health, Medicine and Caring Sciences, Division of Diagnostics and Specialist Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart Center, Department of Clinical Physiology in Linköping.
    Ekström, Magnus
    Lund Univ, Sweden.
    Hedman, Kristofer
    Linköping University, Department of Health, Medicine and Caring Sciences, Division of Diagnostics and Specialist Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart Center, Department of Clinical Physiology in Linköping.
    Systolic Blood Pressure Response to Exercise in Endurance Athletes in Relation to Oxygen Uptake, Work Rate and Normative Values2022In: Journal of Cardiovascular Development and Disease, ISSN 2308-3425, Vol. 9, no 7, article id 227Article in journal (Refereed)
    Abstract [en]

    Work rate has a direct impact on the systolic blood pressure (SBP) during aerobic exercise, which may be challenging in the evaluation of the SBP response in athletes reaching high work rates. We aimed to investigate the exercise SBP response in endurance athletes in relation to oxygen uptake (VO2), work rate and to recent reference equations for exercise SBP in the general population. Endurance athletes with a left-ventricular end-diastolic diameter above the reference one performed a maximal bicycle cardiopulmonary exercise test. The increase in SBP during exercise was divided by the increase in VO2 (SBP/VO2 slope) and in Watts, respectively (SBP/W slope). The maximum SBP (SBPmax) and the SBP/W slope were compared to the predicted values. In total, 27 athletes (59% men) were included; mean age, 40 +/- 10 years; mean VO2max, 50 +/- 5 mL/kg/min. The mean SBP/VO2 slope was 29.8 +/- 10.2 mm Hg/L/min, and the mean SBP/W slope was 0.27 +/- 0.08 mm Hg/W. Compared to the predicted normative values, athletes had, on average, a 12.2 +/- 17.6 mm Hg higher SBPmax and a 0.12 +/- 0.08 mm Hg/W less steep SBP/W slope (p &lt; 0.01 and p &lt; 0.001, respectively). In conclusion, the higher SBPmax values and the less steep SBP/W slope highlight the importance of considering work rate when interpreting the SBP response in endurance athletes and suggest a need for specific normative values in athletes to help clinicians distinguish physiologically high maximal blood pressure from a pathological blood pressure response.

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  • 3.
    Carlén, Anna
    et al.
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart and Medicine Center, Department of Clinical Physiology in Linköping.
    Gustafsson, Mikael
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart and Medicine Center, Department of Cardiology in Linköping.
    Åström, Meriam
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart and Medicine Center, Department of Clinical Physiology in Linköping.
    Nylander, Eva
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart and Medicine Center, Department of Clinical Physiology in Linköping.
    Exercise-induced ST depression in an asymptomatic population without coronary artery disease2019In: Scandinavian Cardiovascular Journal, ISSN 1401-7431, E-ISSN 1651-2006, Vol. 53, no 4, p. 206-212Article in journal (Refereed)
    Abstract [en]

    Objectives. Exercise electrocardiogram (ExECG) in low risk populations frequently generates false positive ST depression. We aimed to characterize factors that are associated with exercise-induced ST depression in asymptomatic men without coronary artery disease. Design. Cycle ergometer exercise tests from 509 male firefighters without imaging proof of significant coronary artery disease were analysed. Analysed test data included heart rate at rest before exercise, and workload, blood pressure, heart rate, ST depression and ST segment slope at peak exercise. ST depression of amp;gt;0.1 mV was considered significant (STdep). With a mean follow-up of 6.1 +/- 1.7 years, medical records were reviewed for cardiovascular diagnoses, hyperlipidemia and diabetes. Logistic regression analysis was used for risk assessment. Results. In total, 22% had STdep in amp;gt;= 1 lead. Subjects with STdep were older than those with normal ExECG (p amp;lt; .001). Downsloping STdep was more common in extremity leads (9%) than in precordial leads (2%). STdep was categorized according to location (precordial/extremity) and slope direction into eight categories. Larger age-adjusted heart rate increase predicted STdep in seven categories (p amp;lt; .05). Age-adjusted peak heart rate correlated with STdep in five categories, predominantly where the ST slope was positive. Peak blood pressure and exercise capacity were both associated with STdep in few categories. We found no association between STdep and hypertension, hyperlipidemia or diabetes (all p amp;gt; .05). Conclusions. In asymptomatic men with a physically demanding occupation and no coronary artery disease, both age and heart rate response were associated with ST depression, whereas common cardiovascular risk factors, blood pressure response and exercise capacity were not.

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  • 4.
    Carlén, Anna
    et al.
    Linköping University, Department of Health, Medicine and Caring Sciences, Division of Diagnostics and Specialist Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart Center, Department of Clinical Physiology in Linköping.
    Lindow, Thomas
    Reg Kronoberg, Sweden; Lund Univ, Sweden.
    Cauwenberghs, Nicholas
    Univ Leuven, Belgium.
    Elmberg, Viktor
    Blekinge Hosp, Sweden; Lund Univ, Sweden.
    Brudin, Lars
    Kalmar Cty Hosp, Sweden.
    Ekstrom, Magnus
    Lund Univ, Sweden.
    Hedman, Kristofer
    Linköping University, Department of Health, Medicine and Caring Sciences, Division of Diagnostics and Specialist Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart Center, Department of Clinical Physiology in Linköping.
    Exercise systolic blood pressure response during cycle ergometry is associated with future hypertension in normotensive individuals2024In: European Journal of Preventive Cardiology, ISSN 2047-4873, E-ISSN 2047-4881Article in journal (Refereed)
    Abstract [en]

    Aims We aimed to investigate the association between the exercise systolic blood pressure (SBP) response and future hypertension (HTN) in normotensive individuals referred for cycle ergometry, with special regard to reference exercise SBP values and exercise capacity.Methods and results In this longitudinal cohort study, data from 14 428 exercise tests were cross-linked with Swedish national registries on diagnoses and medications. We excluded individuals with a baseline diagnosis of cardiovascular disease or HTN. The peak exercise SBP (SBPpeak) was recorded and compared with the upper limit of normal (ULN) derived from SBP(pea)k reference equations incorporating age, sex, resting SBP, and exercise capacity. To evaluate the impact of exercise capacity, three SBP to work rate slopes (SBP/W-slopes) were calculated, relative to either supine or seated SBP at rest or to the first exercise SBP. Adjusted hazard ratios [HRadjusted (95% confidence interval, CI)] for incident HTN during follow-up, in relation to SBP response metrics, were calculated. We included 3895 normotensive individuals (49 +/- 14 years, 45% females) with maximal cycle ergometer tests. During follow-up (median 7.5 years), 22% developed HTN. Higher SBP(peak )and SBPpeak &gt; ULN were associated with incident HTN [HRadjusted 1.19 (1.14-1.23) per 10 mmHg, and 1.95 (1.54-2.47), respectively]. All three SBP/W-slopes were positively associated with incident HTN, particularly the SBP/W-slope calculated as supine-to-peak SBP [HRadjusted 1.25 (1.19-1.31) per 1 mmHg/10 W].Conclusion Both SBPpeak &gt; ULN based on reference values and high SBP/W-slopes were associated with incident HTN in normotensive individuals and should be considered in the evaluation of the cycle ergometry SBP response.Lay summary We examined the systolic blood pressure (SBP) response during maximal bicycle exercise testing in individuals without hypertension (HTN) or established cardiovascular disease and found that:center dot When applying reference values for peak SBP during cycling exercise, accounting for age, sex, resting blood pressure (BP), and exercise capacity, exceeding the upper limit of normal was associated with twice as high relative risk of future HTN, compared with having a peak SBP within normal limits.center dot A steep increase in exercise SBP in relation to the increase in work rate was also associated with future HTN but did not always coincide with elevated peak SBP.

  • 5.
    Carlén, Anna
    et al.
    Linköping University, Department of Health, Medicine and Caring Sciences, Division of Diagnostics and Specialist Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart Center, Department of Clinical Physiology in Linköping.
    Nylander, Eva
    Linköping University, Department of Health, Medicine and Caring Sciences, Division of Diagnostics and Specialist Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart Center, Department of Clinical Physiology in Linköping.
    Gustafsson, Mikael
    Linköping University, Department of Health, Medicine and Caring Sciences, Division of Diagnostics and Specialist Medicine. Linköping University, Faculty of Medicine and Health Sciences. Hjärtspecialisterna i Linköping, Sverige.
    Oklar nytta av upprepade arbets-EKG hos brandmän [Pre-duty medical assessment in fire-fighters requires modernization - relevance of exercise ECG is questioned]2020In: Läkartidningen, ISSN 0023-7205, E-ISSN 1652-7518, Vol. 117Article in journal (Refereed)
    Abstract [en]

    Medical assessment of Swedish smoke diving firefighters includes cardiac evaluation by maximal exercise testing with ECG recording. The exercise ECG procedure for firefighters was introduced in 1986, and remains consistent in the recently updated guidelines from 2019.  Exercise ECG is a non-invasive and easily available method for detection of chronic coronary syndromes, but due to the declining population risk in high-income countries, its ability to accurately detect disease has decreased. Thus, the clinical relevance of exercise ECG in firefighters is questioned and the pre-duty medical assessment requires modernization.

  • 6.
    Carlén, Anna
    et al.
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart and Medicine Center, Department of Clinical Physiology in Linköping.
    Nylander, Eva
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart and Medicine Center, Department of Clinical Physiology in Linköping.
    Åström Aneq, Meriam
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart and Medicine Center, Department of Clinical Physiology in Linköping.
    Gustafsson, Mikael
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart and Medicine Center, Department of Cardiology in Linköping.
    ST/HR variables in firefighter exercise ECG: relation to ischemic heart disease2019In: Physiological Reports, E-ISSN 2051-817X, Vol. 7, no 2, article id e13968Article in journal (Refereed)
    Abstract [en]

    Exercise electrocardiography (ExECG) is regularly performed by Swedish firefighters by law. Heart rate-corrected analysis of ST segment variables (ST/HR) has shown improved prediction of ischemic heart disease (IHD) compared to ST depression alone. This has not previously been extensively studied in asymptomatic persons with a low probability of IHD. We therefore evaluated the predictive performance of ST/HR analysis in firefighter ExECG. ExECG was studied in 521 male firefighters. During 8.4 ± 2.1 years, 2.3% (n = 12) were verified with IHD by catheterization or myocardial scintigraphy (age 51.5 ± 5.5 years) and were compared with firefighters without imaging proof of IHD (44.2 ± 10.1 years). The predictive value of ST depression, ST/HR index, ST/HR slope, and area and rotation of the ST/HR loop was calculated as age-adjusted odds ratios (OR), in 10 ECG leads. Predictive accuracy was analyzed with receiver operating characteristics (ROC) analysis. ST/HR index ≤-1.6 μV/bpm and ST/HR slope ≤-2.4 μV/bpm were associated with increased IHD risk in three individual leads (all OR > 1.0, P < 0.05). ST/HR loop area lower than the fifth percentile of non-IHD subjects indicated IHD risk in V4, V5, aVF, II, and -aVR (P < 0.05). ST depression ≤-0.1 mV was associated with IHD only in V4 (OR, 9.6, CI, 2.3-40.0). ROC analysis of each of these variables yielded areas under the curve of 0.72 or lower for all variables and leads. Clockwise-rotated ST/HR loops was associated with increased risk in most leads compared to counterclockwise rotation. The limited clinical value of ExECG in low-risk populations was emphasized, but if performed, ST/HR analysis should probably be given more importance.

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  • 7.
    Carlén, Anna
    et al.
    Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart and Medicine Center, Department of Clinical Physiology in Linköping. Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine.
    Åström Aneq, Meriam
    Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart and Medicine Center, Department of Clinical Physiology in Linköping. Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine.
    Nylander, Eva
    Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart and Medicine Center, Department of Clinical Physiology in Linköping. Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine.
    Gustafsson, Mikael
    Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart and Medicine Center, Department of Cardiology in Linköping. Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine.
    Loaded treadmill walking and cycle ergometry to assess work capacity: a retrospective comparison in 424 firefighters.2017In: Clinical Physiology and Functional Imaging, ISSN 1475-0961, E-ISSN 1475-097X, Vol. 37, no 1, p. 37-44Article in journal (Refereed)
    Abstract [en]

    The fitness of firefighters is regularly evaluated using exercise tests. We aimed to compare, with respect to age and body composition, two test modalities for the assessment work capacity. A total of 424 Swedish firefighters with cycle ergometer (CE) and treadmill (TM) tests available from Jan 2004 to Dec 2010 were included. We compared results from CE (6 min at 200 W, 250 W or incremental ramp exercise) with TM (6 min at 8° inclination, 4·5 km h(-1) or faster, wearing 24-kg protective equipment). Oxygen requirements were estimated by prediction equations. It was more common to pass the TM test and fail the supposedly equivalent CE test (20%), than vice versa (0·5%), P<0·001. Low age and tall stature were significant predictors of passing both CE and TM tests (P<0·05), while low body mass predicted accomplishment of TM test only (P = 0·006). Firefighters who passed the TM but failed the supposedly equivalent CE test within 12 months had significantly lower body mass, lower BMI, lower BSA and shorter stature than did those who passed both tests. Calculated oxygen uptake was higher in TM tests compared with corresponding CE tests (P<0·001). Body constitution affected approval differently depending on the test modality. A higher approval rate in TM testing suggests lower cardiorespiratory requirements compared with CE testing, even though estimated oxygen uptake was higher during TM testing. The relevance of our findings in relation to the occupational demands needs reconsidering.

  • 8.
    Gustafsson, Charlotte Eklund
    et al.
    Vaxjo Cent Hosp, Sweden.
    Ekstrom, Magnus
    Lund Univ, Sweden.
    Ugander, Martin
    Univ Sydney, Australia; Karolinska Univ Hosp, Sweden.
    Brudin, Lars
    Linköping University, Department of Health, Medicine and Caring Sciences, Division of Diagnostics and Specialist Medicine. Linköping University, Faculty of Medicine and Health Sciences. Kalmar Cty Hosp, Sweden.
    Carlén, Anna
    Linköping University, Department of Health, Medicine and Caring Sciences, Division of Diagnostics and Specialist Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart Center, Department of Clinical Physiology in Linköping.
    Hedman, Kristofer
    Linköping University, Department of Health, Medicine and Caring Sciences, Division of Diagnostics and Specialist Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart Center, Department of Clinical Physiology in Linköping.
    Lindow, Thomas
    Vaxjo Cent Hosp, Sweden; Univ Sydney, Australia; Lund Univ, Sweden.
    Prognostic value of peak work rate indexed by left ventricular diameter2023In: Scientific Reports, E-ISSN 2045-2322, Vol. 13, no 1Article in journal (Refereed)
    Abstract [en]

    Left ventricular diameter (LVEDD) increases with systematic endurance training but also in various cardiac diseases. High exercise capacity associates with favorable outcomes. We hypothesized that peak work rate (W-peak) indexed to LVEDD would carry prognostic information and aimed to evaluate the association between W-peak/LVEDDrest and cardiovascular mortality. W-peak/LVEDDrest (W/mm) was calculated in patients with an echocardiographic examination within 3 months of a maximal cycle ergometer exercise test. Low W-peak/LVEDDrest was defined as a value below the sex- and age-specific 5th percentile among lower-risk subjects. The association with cardiovascular mortality was evaluated using Cox regression. In total, 3083 patients were included (8.0 [5.4-11.1] years of follow-up, 249 (8%) cardiovascular deaths). W-peak/LVEDDrest (W/mm) was associated with cardiovascular mortality (adjusted hazard ratio (HR) 0.28 [0.22-0.36]), similar to W-peak in % of predicted, with identical prognostic strength when adjusted for age and sex (C-statistics 0.87 for both). A combination of low W-peak/LVEDDrest and low W-peak was associated with a particularly poor prognosis (adjusted HR 6.4 [4.0-10.3]). W-peak/LVEDDrest was associated with cardiovascular mortality but did not provide incremental prognostic value to W-peak alone. The combination of a low W-peak/LVEDDrest and low W-peak was associated with a particularly poor prognosis.

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  • 9.
    Hedman, Kristofer
    et al.
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart and Medicine Center, Department of Clinical Physiology in Linköping.
    Carlén, Anna
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart and Medicine Center, Department of Clinical Physiology in Linköping.
    Sunnerud, Sofia
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart and Medicine Center, Department of Cardiology in Linköping.
    Nylander, Eva
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart and Medicine Center, Department of Clinical Physiology in Linköping.
    Janzon, Magnus
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart and Medicine Center, Department of Cardiology in Linköping.
    Hjärtscreening av elitidrottare: Låg följsamhet till RF:s rekommendationer2018In: Idrottsmedicin, ISSN 1103-7652, Vol. 1/18, p. 16-19Article in journal (Other academic)
  • 10.
    Hedman, Kristofer
    et al.
    Linköping University, Department of Health, Medicine and Caring Sciences, Division of Diagnostics and Specialist Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart Center, Department of Clinical Physiology in Linköping.
    Lindow, Thomas
    Lund Univ, Sweden; Univ Sydney, Australia.
    Cauwenberghs, Nicholas
    Univ Leuven, Belgium.
    Carlén, Anna
    Linköping University, Department of Health, Medicine and Caring Sciences, Division of Diagnostics and Specialist Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart Center, Department of Clinical Physiology in Linköping.
    Elmberg, Viktor
    Blekinge Hosp, Sweden; Lund Univ, Sweden.
    Brudin, Lars
    Kalmar Cty Hosp, Sweden.
    Ekstrom, Magnus
    Lund Univ, Sweden.
    Reply to "Blood pressure during moderate or maximal exercise: hardly two sides of the same coin"2022In: Journal of Hypertension, ISSN 0263-6352, E-ISSN 1473-5598, Vol. 40, no 6, p. 1244-1245Article in journal (Other academic)
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  • 11.
    Hedman, Kristofer
    et al.
    Linköping University, Department of Health, Medicine and Caring Sciences, Division of Diagnostics and Specialist Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart Center, Department of Clinical Physiology in Linköping.
    Lindow, Thomas
    Lund Univ, Sweden; Univ Sydney, Australia.
    Cauwenberghs, Nicholas
    Univ Leuven, Belgium.
    Carlén, Anna
    Linköping University, Department of Health, Medicine and Caring Sciences, Division of Diagnostics and Specialist Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart Center, Department of Clinical Physiology in Linköping.
    Elmberg, Viktor
    Blekinge Hosp, Sweden; Lund Univ, Sweden.
    Brudin, Lars
    Kalmar Cty Hosp, Sweden.
    Ekstrom, Magnus
    Lund Univ, Sweden.
    Reply to Pulse pressure amplification is one of the important factors evaluating peripheral blood pressure during exercise2022In: Journal of Hypertension, ISSN 0263-6352, E-ISSN 1473-5598, Vol. 40, no 6, p. 1245-1246Article in journal (Other academic)
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  • 12.
    Hedman, Kristofer
    et al.
    Linköping University, Faculty of Medicine and Health Sciences. Linköping University, Department of Health, Medicine and Caring Sciences, Division of Diagnostics and Specialist Medicine. Region Östergötland, Heart Center, Department of Clinical Physiology in Linköping.
    Lindow, Thomas
    Department of Clinical Physiology, Växjö Central Hospital, Clinical Sciences, Clinical Physiology, Lund University, Department of Research and Development, Region Kronoberg, Sweden; Kolling Institute, Royal North Shore Hospital, University of Sydney, Sydney, New South Wales, Australia.
    Cauwenberghs, Nicholas
    Research Unit Hypertension and Cardiovascular Epidemiology, Department of Cardiovascular Sciences, University of Leuven, Leuven, Belgium.
    Carlén, Anna
    Linköping University, Faculty of Medicine and Health Sciences. Linköping University, Department of Health, Medicine and Caring Sciences, Division of Diagnostics and Specialist Medicine. Region Östergötland, Heart Center, Department of Clinical Physiology in Linköping.
    Elmberg, Viktor
    Department of Clinical Physiology, Blekinge Hospital, Karlskrona, Lund University, Faculty of Medicine, Department of Clinical Sciences Lund, Respiratory Medicine and Allergology, Lund, Sweden.
    Brudin, Lars
    Department of Clinical Physiology, Kalmar County Hospital, Kalmar.
    Ekström, Magnus
    Lund University, Faculty of Medicine, Department of Clinical Sciences Lund, Respiratory Medicine and Allergology, Lund, Sweden.
    Peak exercise SBP and future risk of cardiovascular disease and mortality2022In: Journal of Hypertension, ISSN 0263-6352, E-ISSN 1473-5598, Vol. 40, no 2, p. 300-309Article in journal (Refereed)
    Abstract [en]

    Objectives: This study aimed to evaluate the risk of all-cause mortality and incident cardiovascular disease associated with peak systolic blood pressure (PeakSBP) at clinical exercise testing.

    Methods: Data from 10 096 clinical exercise tests (54% men, age 18-85 years) was cross-linked with outcome data from national registries. PeakSBP was compared with recently published reference percentiles as well as expressed as percentage predicted PeakSBP using reference equations.Natural cubic spline modelling and Cox regression were used to analyse data stratified by sex and baseline cardiovascular risk profile.

    Results: Median [IQR] follow-up times were 7.9 [5.7] years (all-cause mortality) and 5.6 [5.9] years (incident cardiovascular disease), respectively. The adjusted risk of all-cause mortality [hazard ratio, 95% confidence interval (95% CI)] for individuals with PeakSBP below the 10th percentile was 2.00 (1.59-2.52) in men and 2.60 (1.97-3.44) in women, compared with individuals within the 10th--90th percentile. The corresponding risk for incident cardiovascular disease was 1.55 (1.28-1.89, men) and 1.34 (1.05-1.71, women). For males in the upper 90th percentile, compared with individuals within the 10th--90th percentile, the adjusted risks of all-cause death and incident cardiovascular disease were 0.35 (0.22-0.54) and 0.72 (0.57-0.92), respectively, while not statistically significant in women. Spline modelling revealed a continuous increase in risk with PeakSBP values less than 100% of predicted in both sexes, with no increase in risk more than 100% of predicted.

    Conclusion: Low, but not high, PeakSBP was associated with an increased risk of mortality and future cardiovascular disease. Using reference standards for PeakSBP could facilitate clinical risk stratification across patients of varying sex, age and exercise capacity.

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  • 13.
    Hedman, Kristofer
    et al.
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart and Medicine Center, Department of Clinical Physiology in Linköping.
    Sunnerud, Sofia
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart and Medicine Center, Department of Cardiology in Linköping.
    Carlén, Anna
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart and Medicine Center, Department of Clinical Physiology in Linköping.
    Janzon, Magnus
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart and Medicine Center, Department of Cardiology in Linköping.
    Nylander, Eva
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart and Medicine Center, Department of Clinical Physiology in Linköping.
    From guidelines to the sidelines: implementation of cardiovascular preparticipation evaluation in sports clubs is lagging.2019In: British Journal of Sports Medicine, ISSN 0306-3674, E-ISSN 1473-0480, Vol. 53, no 1, p. 3-4Article in journal (Other academic)
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  • 14.
    Lindow, Thomas
    et al.
    Lund Univ, Sweden.
    Ekstrom, Magnus
    Lund Univ, Sweden.
    Brudin, Lars
    Kalmar Cty Hosp, Sweden.
    Carlén, Anna
    Linköping University, Department of Health, Medicine and Caring Sciences, Division of Diagnostics and Specialist Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart Center, Department of Clinical Physiology in Linköping.
    Elmberg, Viktor
    Lund Univ, Sweden; Blekinge Hosp, Sweden.
    Hedman, Kristofer
    Linköping University, Department of Health, Medicine and Caring Sciences, Division of Diagnostics and Specialist Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart Center, Department of Clinical Physiology in Linköping.
    Typical angina during exercise stress testing improves the prediction of future acute coronary syndrome2021In: Clinical Physiology and Functional Imaging, ISSN 1475-0961, E-ISSN 1475-097X, Vol. 41, no 3, p. 281-291Article in journal (Refereed)
    Abstract [en]

    Introduction The prognostic value of angina during exercise stress testing is controversial, possibly due to previous studies not differentiating typical from non-typical angina. We aimed to assess the prognostic value of typical angina alone, or in combination with ST depression, during exercise stress testing for predicting cardiovascular events. Methods We conducted a prospective observational cohort study including all patients who performed a clinical exercise stress test at the department of Clinical Physiology, Kalmar County Hospital between 2005 and 2012. The association between typical angina/ST depression and incident acute coronary syndrome (ACS) and cardiovascular mortality were analysed using Cox regression for long-term and 1-year follow-up. Results Out of 11605 patients (median follow-up 6.7 years), 623 (5.4%) developed ACS and 319 (2.7%) died from cardiovascular causes. Compared to patients with no angina and no ST depression, typical angina and ST depression were associated with increased risk of future ACS; hazard ratio (HR) 3.5 ([95%CI] 2.6-4.7). This association was even stronger for ACS within one year (typical angina with and without concomitant ST depression; HR 20.8 (13.9-31.3) and 9.7 (6.1-15.4), respectively). Concordance statistics for ST depression in predicting ACS during long-term follow-up was 0.58 (0.56-0.60) and 0.69 (0.65-0.73) for ACS within one year, and 0.64 (0.62-0.66) and 0.77 (0.73-0.81), respectively, when typical angina was added to the model. Conclusions Typical angina during exercise stress testing is predictive of future ACS, especially in combination with ST depression, and during the first year after the test.

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  • 15.
    Nordlinder, Johanna Hall
    et al.
    Vaxjo Cent Hosp, Sweden.
    Ekström, Magnus
    Lund Univ, Sweden.
    Brudin, Lars
    Kalmar Cty Hosp, Sweden.
    Elmberg, Viktor
    Lund Univ, Sweden; Blekinge Hosp, Sweden.
    Carlén, Anna
    Linköping University, Department of Health, Medicine and Caring Sciences, Division of Diagnostics and Specialist Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart Center, Department of Clinical Physiology in Linköping.
    Hedman, Kristofer
    Linköping University, Department of Health, Medicine and Caring Sciences, Division of Diagnostics and Specialist Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart Center, Department of Clinical Physiology in Linköping.
    Lindow, Thomas
    Lund Univ, Sweden; Vaxjo Cent Hosp, Sweden; Univ Sydney, Australia.
    Paediatric reference values for the work rate-indexed systolic blood pressure response during exercise2022In: European Journal of Preventive Cardiology, ISSN 2047-4873, E-ISSN 2047-4881, Vol. 29, no 8, p. e283-e285Article in journal (Other academic)
    Abstract [en]

    n/a

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  • 16.
    Sunnerud, Sofia
    et al.
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart and Medicine Center, Department of Cardiology in Linköping.
    Nylander, Eva
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart and Medicine Center, Department of Clinical Physiology in Linköping.
    Janzon, Magnus
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart and Medicine Center, Department of Cardiology in Linköping.
    Carlén, Anna
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart and Medicine Center, Department of Clinical Physiology in Linköping.
    Hedman, Kristofer
    Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart and Medicine Center, Department of Clinical Physiology in Linköping. Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine.
    Låg följsamhet till rekommenderad hjärtscreening av elitidrottare - Lägesanalys i Östergötland2018In: Läkartidningen, ISSN 0023-7205, E-ISSN 1652-7518, Vol. 115, p. 185-187, article id EWLMArticle in journal (Refereed)
    Abstract [en]

    Low adherence to recommended pre-participation cardiac evaluation of Swedish athletes Pre-participation cardiac evaluation of athletes is recommended by international organizations like the European Society of Cardiology and the American Heart Association, as well as by the Swedish Sports Confederation. The purpose of the evaluation is to prevent sudden cardiac death in athletes by early identification of individuals at risk. To our knowledge, no previous study has been made regarding the implementation of pre-participation cardiac evaluation of athletes in Sweden. We performed an electronical survey addressing sports clubs in one out of 21 districts in which the Swedish Sports Confederation is geographically divided. Only four out of 22 responding clubs with elite athletes preformed cardiac evaluation. Lack of knowledge about the recommendations as well as how to perform the evaluation were mentioned as reasons not to evaluate the athletes. Our results indicate the need for more information about pre-participation cardiac evaluation of athletes in Sweden.

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