14-day monitor spots dangerous rhythms after fainting in UK trial

Stephen had already spent a day in hospital after fainting at home. The standard checks found nothing, so the 68-year-old from West Lothian went home. The next day, he passed out on an elliptical trainer. His experience captures the diagnostic problem behind a UK trial: by the time many patients reach the emergency room (ER), their heart rhythm has returned to normal. A 14-day chest monitor offered a longer window, and the trial found dangerous rhythms more often and sooner.

The study involved 2,234 people who arrived at one of 45 UK emergency departments after unexplained fainting. Half received the monitor within 72 hours and wore it continuously for two weeks; the rest received standard care. That usually meant a Holter monitor, a wearable heart recorder worn for only 48 hours, with monitoring starting after a cardiology appointment that could come six weeks to two years after the ER visit.

The difference was visible after one year. Arrhythmias—abnormal heart rhythms—were identified in 22% of the monitored group, against 9% with standard care. They were found after an average of 22 days, compared with 54.5 days. The recordings included complete heart block, ventricular tachycardia and a pause in the heartbeat of more than six seconds. When a serious arrhythmia appeared, clinicians were alerted within 24 working hours after the monitoring period.

Faster and more frequent detection was accompanied by more treatment. 10.8% of patients in the monitor group received antiarrhythmic medication, and 6.8% had a pacemaker implanted, versus 7.3% and 4.6% with standard care. Death rates were 1.5% and 2.9%, respectively. Professor Matthew Reed of the University of Edinburgh said the lower rate was strong evidence that the strategy could save lives; the trial results were presented at the European Society of Cardiology Congress in Munich and published in the New England Journal of Medicine.

And so, concretely? For hospitals, the change is a device placed before a hidden rhythm has time to disappear from the record. For patients, it could mean earlier treatment after a collapse that standard checks miss. It did not reduce the average number of fainting episodes after one year—1.37 with monitoring versus 1.58 with standard care—and the mortality comparison comes from this trial, not a guarantee for every patient. The researchers hope the approach will become standard practice in the NHS, where around 650,000 people visit the ER with unexplained fainting each year.