Teams from the University of Edinburgh and NHS Lothian carried out the first randomised control trial of the device - the AliveCor KardiaMobile - with 243 people presenting with heart palpations or near blackout at 15 Emergency Departments across the UK.
It enabled doctors to diagnose the cause of the palpitations in over 40 per cent more patients than standard tests alone. The device, which can record a patient's heartbeat at home, was also quicker at detecting the cause of palpitations and cut the cost of diagnosis. The researchers, from the University of Edinburgh and NHS Lothian, said it could help save lives.
"We've shown that this device is an easy, cheap way to diagnose heart rhythm problems which usually see people attending emergency departments several times before they're diagnosed," lead author Dr Matthew Reed, from Edinburgh Royal Infirmary, said.
"For those with harmless palpitations this device can quickly give reassurance, whilst for those with serious underlying heart conditions it can act as a lifesaver. We are now calling for this technology to be rolled out in emergency departments across the country."
ECG technology was included in last year's Apple Watch and it could detect a number of heart conditions, such as a low heart rate or arrhythmic beating.
While palpitations are often not serious, they are sometimes caused by underlying heart rhythm disorders such as atrial fibrillation, which can lead to a stroke. However, by the time someone reaches A&E, their symptoms have often subsided and their ECG is normal.
The researchers also gave 124 patients the KardiaMobile device to take home. The device is stuck to the back of a smartphone or tablet and is activated by the patient when they experience a palpitation. The ECG result from the device can then be taken or sent electronically to a doctor to help diagnose the problem.
Meanwhile, 116 patients were given standard tests and, if undiagnosed, told to return to A&E or visit their GP if they experienced more symptoms. After 90 days, the smartphone device helped doctors diagnose 56 per cent of patients, in an average time of 9.5 days. However, only 10 per cent of patients given standard care were diagnosed, in an average time of 43 days.
The technology also cut the cost of diagnosis from £1,395 to £474, the researchers said.
Professor Jeremy Pearson, associate medical director with the British Heart foundation, which co-funded the study, said: "By taking advantage of the tech that we carry around in our pockets every day, this cutting-edge device makes sure that it's easy for people experiencing palpitations to directly record their heartbeat.
"They can then relay the information rapidly to a doctor and improve their diagnosis. This device could spare people from further anxiety, save the NHS money and, more importantly, save lives."
