Atrial fibrillation is a heart rhythm disorder that affects over 30 million people worldwide. The irregular heartbeat can cause blood in the heart's upper chambers – known as the atria - to clot. If such a clot gets into the brain and blocks blood vessels, this can cause a stroke. In older people, atrial fibrillation is one of the most common causes of stroke.
“The big challenge is that atrial fibrillation is often a silent risk factor that can be difficult to detect with current methods. If we are able to better detect atrial fibrillation, then more people could receive treatment for it earlier, and more strokes ought to be prevented,” says Dr. David Gladstone, the study’s principal investigator and stroke neurologist from Sunnybrook Health Sciences Centre and Department of Medicine in the University of Toronto Temerty Faculty of Medicine.
“In clinical practice, we routinely screen for high blood pressure, diabetes, and cholesterol, but proactive screening like this for atrial fibrillation is not currently being done for asymptomatic individuals. New digital health technologies, if used appropriately, hold great promise for improving early detection and treatment of atrial fibrillation, especially for older individuals who are most at risk of developing this arrhythmia,” adds Dr. Gladstone.
The multi-centre, randomised trial, called SCREEN-AF, studied a wearable heart monitor that sticks to the skin, recording every heartbeat and can detect so-called 'silent' atrial fibrillation – atrial fibrillation with no symptoms. The study involved 856 people from 48 GP practices between 2015 and 2019. Participants were 75 years or older and had high blood pressure but no known atrial fibrillation.
Half of the participants received the wearable heart monitor. It was applied to the chest twice for a fortnight at a time. The other half received standard medical care. The device can continuously measure and record someone's heart-beat for a fortnight, after which time it is removed and the data analysed. All participants were followed for six months.
Blood thinners can protect against strokes
The study found that the participants were able to use the device, and that atrial fibrillation was detected ten times more often than in the control group. One out of every 20 patients in the study group was diagnosed with atrial fibrillation. As a result, 75 per cent of those patients were subsequently prescribed blood-thinning medication to protect against strokes.
"The episodes of atrial fibrillation we found were usually several hours long. Blood thinners are generally very effective drugs in those with atrial fibrillation and can reduce stroke risk by almost 70 per cent. However, for the patients we identified, the best possible therapy has not yet been found" says co-study leader Prof. Dr Rolf Wachter from the Heart Center of the University Medical Center Göttingen and the German Centre for Cardiovascular Research (DZHK), Göttingen site.
Around one-third of the participants were contacted in Germany via GP cooperation practices of the DZHK partner institutions Göttingen and Hamburg. "GP practices are ideal partners for future studies on atrial fibrillation screening," adds Prof. Dr Eva Hummers from the Institute of General Medicine at the University Medical Center Göttingen. She led the collaboration with the GP practices.
The study was in JAMA Cardiology.