Smartwatch app can detect heart abnormality, study says
A smartwatch app that monitors heart activity can detect atrial fibrillation, a common heart abnormality that can lead to stroke, according to a study released Wednesday by UCSF researchers.
The study, which will be published in JAMA Cardiology, enrolled 9,750 people — including some who had already been diagnosed with atrial fibrillation before participating in the study— between 2016 and 2017. Participants wore Apple Watches that had the mobile app Cardiogram, which monitors heart rate using a sensor that detects one’s pulse.
The participants with atrial fibrillation wore the smartwatch before and after a treatment known as car-
dioversion, a nonemergency procedure that shocks the heart back into a normal rhythm temporarily. The app was able to distinguish the difference between a normal heart rhythm and and an irregular atrial fibrillation rhythm, the study found.
There have been other examinations into whether smartwatches can detect atrial fibrillation, including by Fitbit, but UCSF’s study is believed to be the first peer-reviewed research indicating so.
An estimated 34 million people worldwide have atrial fibrillation, one of the leading risk factors for stroke, and it often goes undiagnosed because not everyone who has it shows symptoms.
“This is important because atrial fibrillation is extremely common and it’s an important cause of stroke and has been shown to predict heart attack, kidney disease and dementia,” said the study’s senior author, Dr. Greg Marcus, a UCSF cardiologist. “We know blood thinners can prevent stroke and death ... We need to identify the people with atrial fibrillation first. That’s been a major challenge from a public health perspective.”
Tim Allen, a San Francisco resident who participated in the study, was diagnosed with atrial fibrillation two years ago. Allen, 65, said he sometimes feels faint as a result of the condition. He recently underwent a surgical procedure, ablation, that relieved some of the symptoms of atrial fibrillation, but the results may not be permanent, and he continues to take blood thinners to help prevent a stroke.
“Maybe if I had a reliable way to tell (atrial fibrillation) had come back, maybe I wouldn’t have to take a blood thinner preventatively,” Allen said.
Marcus, the cardiologist, said it is too early to recommend using a heart-monitoring app to help diagnose atrial fibrillation.
“The hope is not that these devices are going to make a diagnosis by themselves, but rather will help screen for atrial fibrillation,” he said. “Still, the ultimate diagnosis would need to be made with conventional testing in partnership with a health care professional.”