A pocket-sized monitor that takes an ECG can help detect cardiac arrhythmia in patients with palpitations and pre-syncope who get sent home from the ED without a diagnosis, a study shows.

Such patients were 10 times more likely to have a serious condition detected if they had the device that wirelessly connects to an app on their smartphone to record heart rhythm events, according to British researchers.

In the trial, 124 patients aged 16 and older were randomly assigned to receive the US-developed AliveCor heart monitor on discharge and 116 to receive usual care, which was to re-present to an ED for an ECG if symptoms recurred.

Over the next 90 days, an ECG recording of an arrhythmia was captured in 56% of those using the monitor, compared with just 10% of those given usual care.