Wearable electronic devices could provide early warnings of atrial fibrillation (AF), a growing problem for older adults, new research has shown. A study in Germany, Poland and Spain involving 882 people aged between 65 and 90 points to a relatively simple way of heading off the risk of strokes. Participants who had not been diagnosed with the heart arrhythmia were provided with wristbands containing sensors linked to an app on their mobile phones. Monitoring detected the abnormal heartbeat in 44 of them within 28 days.