News

Treating silent killer cuts risk of stroke and death


20 June 2014

Opportunistic detection of asymptomatic atrial fibrillation (AF) and treating it with anticoagulants can greatly reduce the risk of stroke and premature death, a new landmark study reveals.

AF is a common abnormal heart rhythm that poses the risk of blood clots forming inside the heart. When clots break off they usually travel to the brain, causing severe strokes.

Published in the latest issue of Thrombosis and Haemostasis, the study is the first to reveal the serious risk of stroke, heart attack and death associated with incidentally detected AF.

It shows that finding previously undetected asymptomatic AF carries a doubling of the risk of stroke and a doubling of premature death compared to age and gender matched control subjects.

More positively, the study reveals that treating asymptomatic AF with an oral anticoagulant drug (warfarin) almost completely reversed the increased risk of stroke, and partially reversed the increased risk of death.

It also shows that treating asymptomatic AF with aspirin did not significantly reduce either stroke or death, but still predisposed people to bleeding.

"This study indicates that widespread screening for asymptomatic atrial fibrillation could cost effectively reduce strokes and their associated disability, and help save lives," says study co-author, University of Sydney Cardiology Professor Ben Freedman.

AF is a common and serious heart arrhythmia accounting for 30 per cent of strokes. In 20 to 45 per cent of AF-related strokes this heart arrhythmia hadn't been detected prior to stroke as it is often asymptomatic.

Also, incidentally detected AF isn't usually associated with palpitations or elevated heart rate, which may explain why stroke can be an unexpected and serious first sign of AF.

In another recent study, Freedman and colleagues showed that AF could be detected easily and accurately with a simple, inexpensive ECG using a novel hand-held device attached to an iPhone. The iPhone-based ECG device can diagnose AF within 30 seconds.

"Given such easy ways to detect AF, and our demonstration of the poor outcomes that can be substantially modified by treatment, our results would make a reasonable case to screen for this abnormal heart rhythm in the population, as well as in the clinic," Professor Freedman says.

Fast Facts on atrial fibrillation, screening and treatment:
• Atrial fibrillation (AF) is responsible for one third of all strokes.
• 20 to 45 per cent of AF-related strokes aren't detected prior to stroke because AF is often asymptomatic (no apparent symptioms)
• AF-related strokes are more severe and cause greater disability than non-AF strokes
• Widespread screening for asymptomatic AF among people aged 65 years and over would be a potent way to prevent strokes and the burden of stroke-related harm because AF-related strokes are largely preventable by treatment with oral anticoagulant drugs.

Study co-authors: Dr Carlos Martinez and Anja Katholingfrom the Institute for Epidemiology, Statistics and Informatics, Germany.


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