Listening for disease: heart sound maps provide low-cost diagnosis Shri Radhe Shri Radhe

 stenosis, the narrowing of the aortic valve, is one of the most common and serious heart valve dysfunctions. Usually caused by a build-up of calcium deposits (or sometimes due to a congenital heart defect), this narrowing restricts blood flow from the left ventricle to the aorta and, in severe cases, can lead to heart failure.

The development of sensitive, cost-effective techniques to identify the condition is paramount, particularly for use in remote areas without access to sophisticated technology. To meet this challenge, researchers from India and Slovenia have created an accurate, easy-to-use and low-cost method to identify heart valve dysfunction using complex network analysis.

“Many rural health centres don’t have the necessary technology for analysing diseases like this,” explains team member M S Swapna from the University of Nova Gorica, in a press statement. “For our technique, we just need a stethoscope and a computer.”

Hear the difference

A healthy person produces two heart sounds: the first (“lub”) due to the closing of mitral and tricuspid valves and the second (“dub”) as the aortic and pulmonary valves close, with a pause (the systolic region) in between. These signals contain carry information about the blood flow through the heart, with variations in pitch, intensity, location and timing of the sounds providing essential information related to a patient’s health.

Swapna and colleagues – Vijayan Vijesh, K Satheesh Kumar and S Sankararaman from the University of Kerala – aimed to develop a simple method based on graph theory to identify aortic stenosis heart murmur. To do this, they examined 60 digital heart sound signals from normal hearts (NMH) and hearts with aortic stenosis (ASH). They subjected the signals to fast Fourier transform (FFT), complex network analyses and machine-learning-based classification, reporting their findings in the Journal of Applied Physics.

The researchers first converted each audio signal into a time series. The signal from a representative healthy heart clearly showed the two heart sounds and the separation between them, while signals from hearts with aortic stenosis displayed diamond-shaped murmurs....