Diagnostics
Study finds smartwatch ECG results vary in detecting reduced heart function
Smartwatch ECG results differed by device and over time, so a single negative reading should not rule out reduced heart pumping function.
A Korean study found that artificial intelligence analysis of smartwatch ECG recordings could identify signs of reduced heart pumping function, but results varied by watch brand and across recordings. The preliminary findings were presented at the American Heart Association's Scientific Sessions 2026, according to Medical Xpress.
Among 2,211 patients referred for echocardiography, 9% had different results from the Apple and Samsung watches. MedPage Today reported that 158 people tested positive only on Apple Watch and 42 only on Galaxy Watch. MedPage said 146 people took ECG readings at home, and 49.3% had both positive and negative readings in the same week. Medical Xpress's automatically generated summary instead gave 108 home users and reported that requiring repeated positive results halved false positives but missed two additional cases.
The study defined reduced heart pumping function as an ejection fraction of 40% or less. MedPage reported that the study was conducted at one center and did not assess screening in people without symptoms or heart failure. Researchers said larger studies are needed to determine how smartwatch readings should guide further evaluation.
