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Computerised stethoscope helps doctors diagnose heart defects

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GPs have a new diagnostic tool at their finger-tips: a computerised stethoscope which analyses heartbeats on a standard PC. The stethoscope, designed and built by the University's Heart Sound Group, can be used by GPs in their surgeries to pick up possible heart defects. Patient trials of the device were started this summer. Over 50 cardiac patients at the Royal Sussex County Hospital have volunteered so far to take part.

The stethoscope works by listening to the heartbeats and digitising the sound. The digital data is recorded on computer disk where it is analysed to extract key features. Doctors can examine the screen to spot changes in rhythm which they might not have picked up with an ordinary stethoscope. Each recording is stored so that it can be compared with others made at a later date, revealing whether the condition of the heart has changed.

"The problem with conventional stethoscopes is that they provide very subjective information," says Dr John Torry, head of the Heart Sound Group. "Doctors' impressions of what they are hearing are far less reliable than a quantified digital reading. Most importantly, a computerised stethoscope enables a non-subjective record to be kept of past investigations. Building up a long-term record of the state of the heart makes diagnosing problems easier."

Echocardiograms, machines which bounce ultrasound off the beating heart to produce an on-screen 3D computer image, also help predict heart defects. But their cost of £100,000 puts them out of reach of most general practices. The computerised stethoscope cannot replace the echocardiogram, but at a cost of £2000, it is a cheap and useful tool for GPs.

Two doctoral students, Ed Hebden and Ali Haghighi-Mood, are currently assisting Dr Torry in building up a database of patients' heartbeats. "Classification is the starting-point for diagnosis," said Dr Torry. "The data which we are compiling from hundreds of patients will give GPs a clear idea of what to look for when faced with a possible heart defect."

In particular, the team is trying to identify what kind of trace is typical of sufferers from aortic stenosis, a hardening of one of the valves in the heart. In a year's time they hope to offer GPs software which will recognise the problem in a new patient's trace and assess how far the condition has developed.

This week, at 'Mednet 96' at the Brighton Centre, the team are discussing how heart sound data can be made available to a wider audience using the Internet. Researchers across Europe will be able to examine their material, offering useful medical feedback via the Internet.

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Friday October 18th 1996