Single-Lead ECG Tracings from an Apple Watch Effectively Identifies Patients with a Weak Heart Pump

Patients with a weak heart pump were identified using single-lead ECG tracings from an Apple Watch interpreted by an artificial intelligence (AI) algorithm developed at Mayo Clinic.

Patients were enrolled via email in decentralized, prospective research. Then they downloaded an app that, in the background, securely transferred watch ECGs. The high rate of participation in the study suggests that a scalable tool could be advanced to screen and monitor heart patients for this condition wherever they are.

The research abstract was presented as late-breaking research at the Heart Rhythm Society conference on May 1^st, 2022.

Left ventricular dysfunction—a weak heart pump—afflicts 2% to 3% of people globally and up to 9% of people over age 60. It may have no symptoms, or be associated with shortness of breath, leg swelling, or racing heart beats. What is important is that once we know a weak heart pump is present, there are many lifesaving and symptom-preventing treatments available.

Paul Friedman MD, Chair, Department of Cardiovascular Medicine, Mayo Clinic

Paul Friedman adds, “It is absolutely remarkable that AI transforms a consumer watch ECG signal into a detector of this condition, which would normally require an expensive, sophisticated imaging test, such as an echocardiogram, CT scan, or MRI.”

A standard ECG creates tracing by strategically placing 12 electrode leads on a person’s arms, chest and legs to assess the heart’s electrical signals.

Researchers modified an existing 12-lead algorithm for low ventricular ejection fraction — the weak heart pump — that is licensed to Anumana Inc., an AI-driven health technology company, by nference and Mayo Clinic, to interpret ECG signals produced from the single lead on an Apple Watch.

Earlier Mayo research found that using a 12-lead ECG and an AI algorithm, clinicians can detect a weak heart pump and this knowledge is useful in the office setting. The Food and Drug Administration noted the 12-lead ECG algorithm as a breakthrough device in 2019 and granted emergency use authorization for COVID-19 in 2020.

Itzhak Zachi Attia, Ph.D., the chief AI scientist in the Department of Cardiovascular Medicine at Mayo Clinic, developed an adaptation method that translated single-lead readings into signals that the algorithm could understand. Dr. Attia is the co-director of the Department of Cardiovascular Medicine’s Artificial Intelligence program.

Over the course of the six-month research, participants securely transmitted 125,610 ECGs from 46 states and 11 countries. The average number of times an app was used per month was around two. Overall, the app was well-received, with 92% of people using it more than once. Researchers chose the cleanest readings from each patient’s many ECGs.

Approximately 420 patients had a watch ECG recorded within 30 days of a clinically ordered echocardiogram, or ultrasound of the heart, a standard test to measure pump strength. We took advantage of those data to see whether we could identify a weak heart pump with AI analysis of the watch ECG.

Itzhak Zachi Attia, Lead AI Scientist, Department of Cardiovascular Medicine, Mayo Clinic

Dr. Attia remarks, “While our data are early, the test had an area under the curve of 0.88, meaning it is as good as or slightly better than a medical treadmill test. AI analysis of the watch ECG is a powerful test to identify a weak heart pump.”

The smartphone app that participants in the study used to transfer single lead ECGs from their Apple Watch was developed in collaboration with Mayo Clinic’s Center for Digital Health. The study included 2,454 Mayo Clinic patients who had an iPhone, the Mayo Clinic App, and an Apple Watch Series 4 or later. All prior watch ECGs, as well as new ones recorded by patients, were securely sent to a Mayo secure data platform and were examined there.

The ongoing AI research in cardiology is part of Mayo’s commitment to bringing a digital transformation to health care. Advanced diagnostics that once required travel to a clinic can be accurately done, as this Apple Watch ECG study demonstrates, from a patient’s wrist whether they live in Brazil or Baton Rouge.

Bradley Leibovich MD, Medical Director, Center for Digital Health, Mayo Clinic

“App-based access to a medical center can help address health disparities by making high-level diagnostics accessible to more people in real time,” remarked Bradley Leibovich.

“This test is the first step, as it demonstrates we can get medically useful information from a single-lead watch. Our next steps include global prospective studies to test this prospectively in more diverse populations and demonstrate medical benefit. This is what the transformation of medicine looks like: inexpensively diagnosing serious disease from your sofa,” concluded Dr. Friedman.

The Mayo Clinic provided funding for this research. Apple did not offer any technical or financial assistance. Drs. Attia and Friedman, as well as others, are co-inventors of the Anumana-licensed low ejection fraction algorithm and might benefit from its commercialization.

Dr. Paul Friedman discusses AI to detect weak heart pump. Video Credit: Mayo Clinic.