The advent of smartwatches that retrieve heart physiology both excites and worries physicians. In addition to Apple, a number of companies make wearable ECG monitors for home use.
So are these wearables worth it?
Conclusive evidence about their accuracy and cost effectiveness is lacking, though an Apple-sponsored study from 2019 published in The New England Journal of Medicine suggested they may help to detect some kinds of abnormal heart rhythms, particularly in the elderly. A slew of additional studies is underway, including ones to assess whether a smartwatch can actually help to save lives, or whether mobility measures such as step count lead to fewer heart attacks and hospitalizations.
Most of these at-home ECG watches are designed to record heart rate and detect atrial fibrillation. A-fib, as it’s called, increases the risk of strokes, leading to 150,000 deaths and 450,000 hospitalizations a year. But doctors say that many people have an irregular heartbeat every now and then that doesn’t have clinical implications. Like many new technologies that uncover things in the body that doctors don’t yet fully understand, these devices may alert the user about an irregular heartbeat, but not all irregularities are dangerous.
“It’s like we just invented the microscope and are seeing microorganisms, and we don’t know what they are,” said Dr Harlan Krumholz, director of the Center for Outcomes Research and Evaluation at Yale. Most watches wait to send an alert until there have been about five abnormal beats within an hour or so, rather than after every altered rhythm. Still, that doesn’t mean the abnormality is dangerous.
The American Heart Association agrees that smartwatch monitors could be beneficial, even lifesaving, for some, but Dr Mariell Jessup, the group’s chief science and medical officer, said, “we do not have enough data yet to recommend it for everyone.”
Even electrocardiograms performed at a doctor’s office aren’t routinely recommended for everyone. The U.S. Preventive Services Task Force, a group of experts that advises on screening tests, says there is not enough evidence to show that routine ECGs are effective and worries about the costs, and potential dangers, of further testing.
And doctors worry that as more and more people wear these devices that might spot meaningless heart arrhythmias, there could be a flood of unnecessary follow-up testing and too much treatment.
