Application of the cone-kernel distribution to study the effect ofmyocardial contractility in the genesis of the first heart sound in dog

摘要

In order to examine the effect of myocardial contractility in theproduction of the first heart sound (S1), the cone-kernel distribution(CKD) was applied to the thoracic S1 in dogs under various cardiaccontractile states. The results showed that the dominant components ofS1 are highly concentrated in a specific frequency band between 30 and50 Hz with a horizontal flat or a semi-lunar shape, independent of themyocardial contractile state. There was no systematic increasingfrequency component in the signal distributions like that found in themuscle sound. These results suggest that the myocardial contribution inS1 may be absent. However, there is some evidence that the myocardialcontribution may be obscured by the other stronger components, and thuscannot be detected by the time-frequency representation (TFR) techniques