Could the stethoscope be on its way to becoming a quaint instrument from yesteryear? Well, maybe. German scientists are reporting success in using radar to monitor people’s heartbeats, and the technology could allow for more accurate diagnoses of heart maladies.
One of the problems with stethoscopes is the fact that when it comes to diagnosing conditions such as heart murmurs, the assessment is based on the opinion and experience of the doctor who’s listening to the patient’s heartbeat.
That’s why electronic engineers from Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU) developed what they claim is a more objective radar-based system. Created in a partnership with the Brandenburg University of Technology and Universitätsklinikum Erlangen, it measures micrometer-scale vibrations of the patient’s chest, which are caused by the beating of the heart.
"In principle, we’re using a similar method to detecting speed in road traffic," says FAU doctoral candidate Christoph Will. "During this process, a radar wave is aimed at the surface of an object and reflected. If the object moves, the phase of the reflecting wave changes. This is used to calculate the strength and frequency of the movement – of the chest in our case."
When tested on volunteers who were either resting or who had just performed vigorous activities, the radar system was found to have a 92-percent correlation rate with an electrocardiograph (ECG). The slight discrepancy was reportedly due to the fact that the radar system couldn’t read the same part of the chest at the same time as the ECG.
It is now hoped that once developed further, the technology could be used as a human-error-free alternative to stethoscopes, digitally detecting and assessing tiny variations in the heartbeat that could indicate problems.
Scientists from Japan’s Kyoto University are also working on a radar-based heart rate-tracking system.