34 Cardiac Murmur Classification Based on Analysis of the Phonocardiogram to Estimate the Number of Degrees of Freedom of the Heart Modelled as a Nonlinear System

Almost all cardiac abnormalities manifest themselves as an aberration in the normal phonocardiogram (PCG). Such aberrations are called murmurs, and locating a cardiac murmur in the PCG, to study physical characteristics of the underlying abnormality, is the first step in computer assisted cardiac diagnosis. In this paper we present a method to quantify visual simplicity of heart sounds that is independent of the sound absolute amplitude and frequency, while resulting in better characterization of murmurs. Then, we show that the simplicity of the systolic time interval assumes well defined patterns in the presence of systolic murmurs that can be used to classify them according to their location in systole and their most probable mechanism of production.