An artificial intelligence (AI) model that analyzes heart signals from smartwatches may help detect left ventricular systolic dysfunction (LVSD), a condition in which the heart's main pumping chamber does not contract effectively, according to preliminary research presented at the American Heart Association's Scientific Sessions 2026. The study, which was independent and late-breaking, evaluated whether AI could identify people who need further screening, such as an echocardiogram.
LVSD is defined in the study as a left ventricular ejection fraction of 40% or less, meaning the heart pumps out no more than 40% of the blood it contains with each beat. It can be present without symptoms and, if untreated, may lead to symptomatic heart failure. The research, conducted at Incheon Sejong Hospital in South Korea, involved two groups of adults. In the first group, 2,211 adults scheduled for an echocardiogram had ECGs recorded on both an Apple Watch and a Samsung Galaxy Watch during the same visit. The AI model distinguished people with and without LVSD about equally well on both watches. However, when the same AI-score cutoff was applied, 200 participants (9%) were classified as positive on one watch and negative on the other.
A second group of 146 adults recorded ECGs at home using their own smartwatches, with 94% using a Galaxy Watch. Among 108 participants who recorded on at least five days in the first week, requiring positive results on at least 2 of 3 consecutive days halved false-positive classifications compared to acting on a single positive day (from 18 to 9 among 70 people without LVSD). This approach identified 31 of 38 participants with LVSD, compared with 33 when single-positive days were analyzed, meaning two additional cases were missed. The findings suggest that smartwatch ECGs analyzed with AI may help flag individuals who need additional heart screening, but more research is needed before these readings can replace traditional exams.
"Some people have reduced heart pumping function without noticeable symptoms," said study author Hak Seung Lee, M.D., FAHA, chief medical officer of Medical AI Co., Ltd., which developed the AI model, and a cardiologist at the Digital Healthcare Institute, Sejong Medical Research Institute in Incheon, South Korea. "Our study explored whether AI analysis of smartwatch ECGs could help identify people who may benefit from additional screening for LVSD or other heart conditions." Lee also noted, "A single smartwatch ECG is a snapshot, and repeated recordings can give different results. Requiring repeated positive results reduced false positives in our study, yet it also missed some additional cases that should have been positive. Larger studies are needed to determine how best to use these results to guide further evaluation."
The study has several limitations: it was conducted at a single hospital and included patients referred for echocardiography, so results may not apply to the general population; the comparison of repeat-testing rules included only 108 participants; and the study did not determine whether using these AI results leads to earlier treatment, fewer hospitalizations, or improved survival. The findings are considered preliminary until published as a full manuscript in a peer-reviewed journal, and the abstract is available in the American Heart Association's Online Program Planner.
For readers, the research points to a potential future in which consumer smartwatches could serve as a first-line screening tool for hidden heart conditions, prompting earlier medical evaluation. However, the variability between brands and the trade-off between false positives and missed cases underscore that such tools are not yet ready to replace standard diagnostic tests like echocardiograms. The American Heart Association provides resources on ejection fraction heart failure measurement and quality improvement programs such as Get With The Guidelines® - Heart Failure. The association's financial information is available here, and more details can be found on heart.org and stroke.org. The original release is posted on www.newmediawire.com.
