Patients may one day be able to carry out life-saving heart tests at home - using just a webcam. A new procedure, which includes a 15-second face scan, is being developed which is capable of detecting tiny changes in skin colour. Data gathered from the scan will help doctors determine whether patients are suffering from an irregular heartbeat. With the help of a webcam and new software, the new 15-second test can detect atrial fibrillation (AF), a treatable but potentially dangerous heart condition characterised by irregular heartbeat. The technology records the subtle changes in skin colour which occur due to uneven blood flow caused by AF. These changes are so slight that they are invisible to the naked eye. However the skin on the face is thinner than other parts of the body and blood vessels are closer to the surface, so this is the ideal place to detect AF, say the researchers. AF is one of the most common heart rhythm problems, and affects up to 800,000 people in the UK. It significantly raises the risk of stroke, because it means the upper chambers of the heart do not pump efficiently, potentially causing blood clots. A normal heart rate should be between 60 and 100 beats a minute when at rest. In extreme cases, the condition can cause heart failure and has also been linked to Alzheimer's disease by reducing blood flow to the brain. The technology was developed by the University of Rochester School of Medicine and Dentistry in conjunction with Xerox. Dr Jean-Philippe Couderc, of Rochester University, in the U.S., said the new technology means AF can be diagnosed without hooking the patient up to an electrocardiogram (ECG) machine, as is currently necessary. He said: ‘This technology holds the potential to identify and diagnose cardiac disease using contactless video monitoring.' He added: ‘This is a very simple concept, but one that could enable more people with atrial fibrillation to get the care the care they need.’ The technology works because sensors in digital cameras record the different wavelengths of light: red, green, and blue. Haemoglobin - a component of blood – ‘absorbs’ more of the green spectrum of light and this subtle change can be detected by the camera's sensor. So the camera can detect the uneven blood flow caused by AF by detecting higher levels of haemoglobin. Scientists were able to verify the technology was working accurately by simultaneously hooking patients up to an electrocardiogram (ECG) so results from the facial scan could be compared to the actual electrical activity of the heart. The study, which was published online in the journal Heart Rhythm, found that the colour changes detected by video monitoring corresponded with an individual's heart rate as detected on an ECG. The study found that the video monitoring technique - which researchers have dubbed ‘videoplethymography’ - had an error rate of 20 per cent, compared with the 17 to 29 per cent error rate associated with automated ECG measurements. Researchers are now in the process of evaluating the technology on a larger study population, including those without atrial fibrillation. However Dr Couderc said that the technology could be developed to be more accurate and accessible. He said: ‘This study was intended to be a proof of concept and, as is the case with many new technologies, we believe that we can significantly improve its accuracy and the usability.’ Source
