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Three‐axis seismocardiography using a low‐cost geophone accelerometer
Author(s) -
Shell Jared B,
Peters Randall D,
Russell Michael J
Publication year - 2007
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.21.6.a1261-c
Subject(s) - accelerometer , preload , contractility , geophone , cardiology , supine position , medicine , physics , acoustics , hemodynamics , quantum mechanics
Seismocardiography (SCG) is the non‐invasive measurement of accelerations in the chest wall produced by myocardial movement. Single‐axis SCG has been used to assess ventricular function in post‐MI patients following exercise testing, to monitor contractility in weightless environments, and to monitor myocardial ischemia during magnetic resonance imaging. In the present study we used a low‐cost, low frequency geophone accelerometer in conjunction with a triaxial accelerometer to examine chest wall accelerations in male (n = 15) and female patients (n = 12) considered to have normal cardiac function. Patients were fitted with a single‐lead ECG and a pulse plethysmograph to correlate cardiac timing and pulse information. Accelerations were recorded in three axes: x (left‐right), y (toe‐head), and z ( back‐front) at 1000 Hz. Single‐beat recordings from each axis were averaged over 5 beats and combined to form a three‐dimensional vector diagram representing acceleration magnitude. Comparisons were made between accelerations recorded in supine individuals at rest, during leg elevation (preload), and following a short period of moderate exercise. No change was noted in the magnitude of accelerations produced in the x, y, or z planes with increased preload. Significant increases were noted in both men and women in the y and z axes following moderate exercise, whereas accelerations were unchanged across the x axis. These results show that increased contractility associated with moderate exercise produces quantifiably different acceleratory effects than preload and may provide a novel method for low‐cost, long‐term monitoring of cardiac contractility at the primary care level.