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HKU study finds that home blood pressure machine may give false detection of atrial fibrillation in young people

28 Jan 2015

Researcher from the Li Ka Shing Faculty of Medicine, The University of Hong Kong (HKU) found that a home blood pressure machine designed to automatically detect irregular heartbeat caused by atrial fibrillation may give false detection in young people.  The result has been published recently in the British Medical Journal Case Reports.

Research Implications
“Finding atrial fibrillation in elderly people will help to prevent future strokes, but we should not use automatic atrial fibrillation detection in younger patients because of the high chance of false alarm,” said Professor Bernard Cheung Man-yung, Sun Chieh Yeh Heart Foundation Professor in Cardiovascular Therapeutics, Clinical Professor of Department of Medicine, Li Ka Shing Faculty of Medicine, HKU.

Research Findings
This research is a school project using the blood pressure machine to check the blood pressure in schoolboys.  A total of 60 normal healthy male teenagers, aged 13-18 years have participated in the project.  Results showed that the machine detected normal variation in the heart rate as atrial fibrillation in 18% of the boys.  Having a variable heart rate is a sign of good health.  The false positives may therefore cause unnecessary worry and medical consultations.

Research Background
A home blood pressure machine with built-in atrial fibrillation detection is recommended by experts and UK guidelines so that patients with atrial fibrillation but without symptoms can be identified for treatment with the new oral anticoagulants to prevent stroke.  This is a good idea in the elderly amongst whom atrial fibrillation is common, but in younger persons in whom atrial fibrillation is exceedingly rare, this function is best switched off because of the false alarms.

About Atrial Fibrillation (AF)
AF is a common disorder in the heart rhythm in the elderly, affecting about 7% of the elderly in the general population.  The heart beat becomes totally irregular.  Patients with this condition may complain of palpitations and breathlessness.  In AF, blood clots can form in the atrium of the heart and if these travel to the brain, can cause stroke.  An anticoagulant is often given to these patients to prevent this type of complication.  However, it is quite uncommon of AF among young people, fewer than 0.1%.