Time-frequency analysis of systolic murmurs

Many pathological conditions produce heart murmurs which may or may not be audible during auscultation. The significance of murmur during auscultation generally alerts the examiner for further medical investigations such as Doppler test, ultrasonic imaging or cardiac catheterisation. This approach, however, has not proved efficient. There are many cases in which auscultation fails to discriminate benign from pathological murmurs. On the other hand the presence of other cardiac sounds may mask pathological murmurs, resulting in exempting potential cardiac patients from further examination. Due to these possibilities, an intermediate objective method capable of estimating the severity of heart murmurs has been always desirable. This paper addresses the characteristics of heart murmurs from signal theory point of view and suggests an appropriate signal analysis method which is capable of describing the dynamics of heart murmurs. The result of a pilot study using the proposed method indicates a distinctive pattern for time-frequency distribution of heart murmurs which is expected to provide information of diagnostic importance.