Analysing paediatric heart murmurs with discriminant analysis

Heart murmurs are sounds produced by the turbulent flow of blood in the cardiovascular system which result from certain conditions in the heart. Atrial Septal Defect (ASD) and Ventricular Septal Defect (VSD) are two common heart diseases found in children causing murmurs during systole. The acoustic qualities of the two murmurs are, however, somewhat different. The aim of this paper is to characterise these two kinds of murmurs and the normal systolic sounds so that classification can be carried out more easily. Three groups of patients with the above heart conditions were studied. The systolic signals were characterised in the time-frequency domain by a representation based on the averaged spectrogram from which the spectral features were extracted to form feature vectors. Discriminant analysis was then performed to project the higher dimensional spectral features onto a two-dimensional space, in which the three groups form natural clusters and can be linearly classified.