Coronary artery disease is a major cause of death in industrialised nations. Approximately 13 million people in the United States alone are estimated to suffer from it.

The condition is caused by the thickening and hardening of arterial walls as substances such as fat, cholesterol and calcium, accumulate in the arteries. This causes them to become narrow, potentially leading to chest pain, heart attacks and sudden death.

There is an urgent need for a non-invasive way to detect these conditions, says John Semmlow at the University of Medicine and Dentistry of New Jersey, who has developed a smart stethoscope connected to a computer that could do the trick.

His idea is based on the principle that blood flow through restricted arteries sounds different to the flow through healthy vessels. The device listens to the noise that the blood makes as it flows though the heart, filters out any unwanted background noise and then looks for the telltale signs that artery disease is present.
(source : http://www.newscientist.com/blog/invention )