Multi-sensor stethoscope excels at detecting faulty heart valves

Valvular heart disease (VHD) is a potentially fatal condition, yet it's difficult to diagnose with a regular stethoscope. A possibly life-saving new multi-sensor stethoscope is claimed to be much better at the job, with the added benefit that it can be used by just about anyone.

VHD occurs when one or more of the heart's four valves don't open or close properly, leading to blood flow issues. According to the American Heart Association, the malady ranks among the highest contributors to global deaths from cardiovascular disease.

Unfortunately, the condition can be quite advanced by the time symptoms become noticeable. Even then, those symptoms are often misdiagnosed as being caused by respiratory ailments – this can happen even when a general practitioner listens to the patient's heart with a conventional single-sensor stethoscope.

Performing an echocardiogram is the best way of diagnosing VHD, but it requires specialized, expensive, hospital-based equipment operated by trained personnel. As a result, patients often have to wait up to several months before they can get tested.

That's where the new electronic stethoscope is intended to come in.

Developed by Prof. Anurag Agarwal and colleagues at the University of Cambridge, the flexible handheld device is about the size and shape of a drink coaster, and it incorporates not one but six vibration-detecting piezoelectric sensors.

An exploded view of the stethoscope, with the six piezoelectric sensors visible in a pentagon pattern at the bottom

Those sensors are separated from one another by a vibration-absorbing silicone gel, allowing each one to operate completely independent of the others. Signal-quality-assessing algorithms automatically select the sensors that are receiving the best readings, ignoring those that lack sufficient diagnostic quality.

This multi-sensor design reportedly makes the device much better at detecting the telltale heart sounds associated with VHD, enough so that it can be used overtop of clothing by people with little training – possibly even by the patients themselves.

Its recordings are analyzed by a machine-learning-based algorithm on a hardwired computer, which in the future could be replaced by a Bluetooth-linked smartphone. So far, computer models indicate that the algorithm should outperform general practitioners at accurately diagnosing VHD.

The device has already been tested on 40 healthy test subjects of various body sizes, half of them male and half of them female. Plans now call for clinical trials to be performed on VHD patients, with the readings being compared to those obtained via echocardiograms.

"To help get waiting lists down, and to make sure we’re diagnosing heart valve disease early enough that simple interventions can improve quality of life, we wanted to develop an alternative to a stethoscope that is easy to use as a screening tool," says Agarwal. "If successful, this device could become an affordable and scalable solution for heart health screening, especially in areas with limited medical resources."

A paper on the research was recently published in the IEEE Journal of Biomedical and Health Informatics.

Source: University of Cambridge

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