Heart sounds based measures of cardiac status for heart failure patient management

Heart sounds based measurements such as S3 amplitude and systolic timing intervals (STIs) are known to be indicative of cardiac dysfunction. In this paper we investigate the correlation of these measurements from pacemaker device implant locations to echocardiographic hemodynamic metrics of E wave deceleration time (EDT), Ejection Fraction (EF) and Stroke Volume (SV). Simultaneous heart sounds and echocardiography measurements were made in 6 heart failure patients with cardiac resynchronization therapy (CRT) devices prior to CRT activation (baseline) and at 3 and 6 months post-CRT. In N=17 datasets, S3 amplitude was correlated to EDT (r=-0.86, p<0.05). Similarly STIs such as heart sounds based pre-ejection period (HSPEP) was correlated with EF (r = -0.81, p<0.01) and ejection time (HSET) with SV (r = 0.65, p=0.01). Longitudinal analysis in each patient showed consistent changes between % increase in S3 vs. % decrease in EDT (r= -0.83, p<0.01), % change in HSPEP vs. % change in EF (r= -0.80, p=0.03) and % change in SV (r= -0.72, p< 0.01). These results show proof of concept for using pacemaker derived measurements for monitoring HF patients. Further study is needed to determine their efficacy for chronic monitoring of HF patients.