Tried and tested technique
When a doctor listens to the heart with their stethoscope they place it on various points on the chest to pick up the heart valve sounds and their training will enable them to pick up the underlying sounds inside. ‘What we are doing,’ Plumbley explains, is using ‘the fact that the heart sound pretty much repeats itself.’ They line up the heart valve sounds using a technique called independent component analysis.

The Digiscope is connected, preferably wirelessly, to a laptop running the software. The heart sounds change very slightly depending on whether the patient is breathing in or breathing out, so the software will look for the best alignment, which is presented graphically.  

Remote heart screening
Plumbley believes that this technology will make it easier for cardiologists to find abnormalities more quickly. ‘With this heart sound separation technology, once it’s been tested, it will make it easier to spot things on a chart or if there is a query, the recordings can be sent off to an expert in another hospital for a second opinion.’

At the moment a couple of the prototypes are being tested in hospitals in Portugal and in Brazil. The next stage is to make it more robust and get the sound synchronisation technology more automated so it can ignore sounds not heart-generated such as the doctor moving the DigiScope. They also want to test it in a wider range of hospitals to see how people use it. Plumbley is very positive about his team’s experience, ‘from our point of view it is great to be involved in this type of collaborative multi-national interdisciplinary project. We are working with medical research experts so that means that we can get work done that wouldn’t be possible in any one group alone.’