Detection of the Third Heart Sound Using Hilbert-Huang Transform

Existence of the third heart sound is an indication of heart failure. In this paper, a novel method is proposed to detect the presence of the third heart sound. A time-frequency analysis method, Hilbert-Huang transform, was used to decompose the signal adaptively and to acquire the instantaneous frequency. Further extraction of the maximal instantaneous frequency and its magnitude is performed to a heart sound signal to distinguish the third heart sound which is usually with lower frequency as well as lower amplitude. A frequency-magnitude distribution was plotted, and the results showed the difference between a normal heart sound and a heart sound with the third heart sound.