Detection of Normal and Paradoxical Splitting in Second Heart Sound (S2) using a Wearable Accelerometer Contact Microphone.

Second heart sound (S2) splitting can potentially be used as an indicator for diagnosis of cardiovascular diseases. One example is S2 paradoxical splitting, which can occur when the pulmonic sound (P2) occurs before the aortic sound (A2). However, current means of capturing S2 sounds are not sensitive enough for quantification of A2 and P2. In this paper, we present that S2's acoustic signatures can be captured accurately using a wearable hermetically sealed sensitive accelerometer contact microphone (ACM) MEMS device. Smoothed Pseudo Wigner-Ville distribution is used to extract the S2 splitting interval. This methodology has been used to capture S2 splitting from patients with varying BMI and used to identify paradoxical splitting from patients with known heart diseases such as aortic stenosis.