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(556) – Change in Acoustic Fingerprints at Increased Pump Speed During Echocardiographic Ramp Test
Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Cardiology in Linköping.ORCID iD: 0000-0001-5485-1052
Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Thoracic and Vascular Surgery.
Skane University Hospital, Lund.
Division of Transplant and Assist Devices at Methodist DeBakey Heart & Vascular Centre, Houston, Texas, USA.
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2014 (English)Conference paper, Poster (with or without abstract) (Refereed)
Abstract [en]

Purpose

The continuous flow mechanical circulatory support HeartMate II (Thoratec Corporation, Inc. Pleasanton, USA) (HMII), generates an auditory signal (acoustic fingerprint) that can be registered by routine auscultation. A temporary or permanent change in sound indicates a change in pump function. Previous mock loop studies have shown that changes in acoustic fingerprint are due to changes in speed, so the aim of this study was to see if the acoustic fingerprint changed during an echocardiographic ramp test.

Methods

Four stable, event-free patients included in the SoundMate study performed an echocardiographic ramp test. The speed was increased stepwise by 400 rpm between 8 000 and 12 000 rpm, and the left ventricular end diastolic diameter, flow, power consumption and blood pressure were measured. Sounds from HMII were recorded using an iPhone™ (Apple Inc. Cupertino, CA, USA) with the stethoscope application iStethPro™ (Dr. Peter J Bentley, UK) and the frequency map analyzed using the Audacity™ program (Unicode, Ash, Chinen and Crook, USA). The acoustic fingerprint is divided into regions (R1: 1 000-6 500, R2: 8 500-14 000, R3: 15 000-21 000 Hz) and peaks (P1: 0-1 000, P2: 6 500-8 500, P4: 21 000-23 000 Hz) in order to facilitate calculations and clarify changes in frequency.

Results

There were significant (p<005) changes in the acoustic fingerprint when increasing the pump speed between 8 000 and 12 000 rpm. In 2/4 patients there were no significant changes in P1, otherwise there were significant changes in all regions and peaks. During the ramp test the power increased in mean 7 W, flow 3,1 L/min and the blood pressure measured with Doppler increased by ~15 mmHg. The left ventricular size decreased with ~2 cm.

Conclusion

The acoustic fingerprint changes with pump speed. This implies that when using sound check for detection of pump dysfunction, a new baseline should be set after every adjustment of speed.

Place, publisher, year, edition, pages
Elsevier, 2014. Vol. 32, no 4S, S206- p.
National Category
Clinical Medicine
Identifiers
URN: urn:nbn:se:liu:diva-114003DOI: 10.1016/j.healun.2014.01.898ISI: 000333866700557OAI: oai:DiVA.org:liu-114003DiVA: diva2:786362
Conference
34th Annual Meeting and Scientific Sessions of the International-Society-for-Heart-and-Lung-Transplantation
Available from: 2015-02-05 Created: 2015-02-05 Last updated: 2017-06-29

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Sundbom, PerAhn, HenrikGranfeldt, Hans

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Division of Cardiovascular MedicineFaculty of Health SciencesDepartment of Cardiology in LinköpingDepartment of Thoracic and Vascular Surgery
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CiteExportLink to record
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