Analysis of the second heart sound for measurement of split

Abstract

A2 and P2 are the two components of the second heart sound S2. A2 is the sound produced by the closing of the aortic valve and P2 is due to the closing of the pulmonary valve. Usually the pulmonary valve closes after the aortic valve. The closure of the two valves introduces a time delay. This delay is known as split. Discrete wavelet transform (DWT) and continuous wavelet transform (CWT) are used to measure the split between the two components of A2 and P2 of second heart sound of normal and pathological case of Phonocardiogram (PCG) signal. To recognize the split, A2 and P2 are identified and delay between the A2 and P2 are estimated. DWT is used to find the split between the two components and continuous wavelet transform is used to find the number of frequency components of S1 and S2. Split between the two components is measured by the continuous wavelet transform. Also normalized split Zn can be calculated. If Zn is less than one, the split is the normal otherwise, it is pathological split.