Per Sundbom1,2, Michael Roth3, Hans Granfeldt2,4, Daniel M Karlsson5, Henrik Ahn2,4, Fredrik Gustafsson3, Laila Hubbert2,6. 1. 1 Department of Medicine and Geriatrics, Höglandssjukhuset, Eksjö, Sweden. 2. 2 Department of Medicine and Health Sciences, Linköping University, Linköping, Sweden. 3. 3 Department of Electrical Engineering, Linköping University, Linköping, Sweden. 4. 4 Department of Thoracic and Vascular Surgery, Linköping University, Linköping, Sweden. 5. 5 Department of Biomedical Engineering, Linköping University, Linköping, Sweden. 6. 6 Heart and Vascular Theme, Karolinska University Hospital and Department of Medicine, Solna, Karolinska Institutet, Stockholm, Sweden.
Abstract
INTRODUCTION: The use of left ventricular assist device (LVAD) has grown rapidly. Adverse events do continue to occur. In recent years, analysis of LVAD sound recordings emerged as a means to monitor pump function and detect pump thrombosis. The aim of this study was to characterize the sounds from HeartMate II and to evaluate the use of handheld iOS devices for sound recordings. METHOD: Signal analysis of LVAD sound recordings, with dedicated recording equipment and iOS devices, was performed. Two LVADs running in mock loop circuits were compared to an implanted LVAD. Spectral analysis and parametric signal models were explored to quantify the sound and potentially detect changes in it. RESULTS: The sound recordings of two LVADs in individual mock loop circuits and a third one implanted in a patient appeared to be similar. Qualitatively, sound characteristics were preserved following changes in pump speed. Recordings using dedicated equipment showed that HeartMate II sound comprises low-frequency components corresponding to pump impeller rotation, as well as high-frequency components due to a pulse width modulation of the electric power to the pump. These different signal components interact and result in a complicated frequency spectrum. The iPhone and iPod recordings could not reproduce the sounds as well as the dedicated equipment. In particular, lower frequencies were affected by outside disturbances. DISCUSSION: This article outlines a systematic approach to LVAD sound analysis using signal processing methods to quantify and potentially detect changes, and describes some of the challenges, for example, with the use of inexpensive recording devices.
INTRODUCTION: The use of left ventricular assist device (LVAD) has grown rapidly. Adverse events do continue to occur. In recent years, analysis of LVAD sound recordings emerged as a means to monitor pump function and detect pump thrombosis. The aim of this study was to characterize the sounds from HeartMate II and to evaluate the use of handheld iOS devices for sound recordings. METHOD: Signal analysis of LVAD sound recordings, with dedicated recording equipment and iOS devices, was performed. Two LVADs running in mock loop circuits were compared to an implanted LVAD. Spectral analysis and parametric signal models were explored to quantify the sound and potentially detect changes in it. RESULTS: The sound recordings of two LVADs in individual mock loop circuits and a third one implanted in a patient appeared to be similar. Qualitatively, sound characteristics were preserved following changes in pump speed. Recordings using dedicated equipment showed that HeartMate II sound comprises low-frequency components corresponding to pump impeller rotation, as well as high-frequency components due to a pulse width modulation of the electric power to the pump. These different signal components interact and result in a complicated frequency spectrum. The iPhone and iPod recordings could not reproduce the sounds as well as the dedicated equipment. In particular, lower frequencies were affected by outside disturbances. DISCUSSION: This article outlines a systematic approach to LVAD sound analysis using signal processing methods to quantify and potentially detect changes, and describes some of the challenges, for example, with the use of inexpensive recording devices.
Entities:
Keywords:
HeartMate II; left ventricular assist device; sound; spectral analysis
Authors: Beren Semiz; Sinan Hersek; Maziyar Baran Pouyan; Cynthia Partida; Leticia Blazquez-Arroyo; Van Selby; Georg Wieselthaler; James M Rehg; Liviu Klein; Omer T Inan Journal: IEEE J Biomed Health Inform Date: 2020-01-13 Impact factor: 5.772