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Researchers have developed a new app that successfully uses an Apple Watch to monitor signs of left-ventricular dysfunction. Sellwell/Getty Images
  • A new study indicates that an Apple Watch app may be useful in detecting left-ventricular dysfunction.
  • Left-ventricular dysfunction is a condition where the heart cannot pump properly.
  • The app used in the study performed similarly to a traditional 12-lead electrocardiogram.
  • Experts say this may enable patients to detect and monitor heart failure without an office visit.

A Mayo Clinic study presented on May 1, 2022 at the Heart Rhythm 2022 conference in San Francisco, California, found that a new Apple Watch app using artificial intelligence (AI) to analyze data from the watch may be useful in detecting left-ventricular dysfunction.

Left-ventricular dysfunction is a type of heart failure in which one of the chambers of the heart, the left ventricle, becomes weakened, leaving the heart unable to adequately pump blood throughout the body.

It may be caused by chronic or badly-controlled high blood pressure or by damage to the heart muscle due to coronary artery blockage.

People with heart failure may experience symptoms such as:

  • shortness of breath
  • fatigue
  • swollen legs and abdomen
  • coughing
  • weight gain
  • nausea
  • chest pain
  • racing heart beat

They may also have no noticeable symptoms.

Mayo Clinic patients who had an Apple Watch and were willing to download the Mayo Clinic iOS app were invited to take part in the study.

The Apple Watch was used for the study because its Series 4, 5, 6, and 7 watches have a sensor which is capable of detecting the electrical impulses indicative of the heart beat and its rhythm.

This data can be used to determine the presence of atrial fibrillation (irregular heart rhythm).

Altogether, 2,454 people from 46 states and 11 countries participated. The average age of study participants was 53 years and 56 percent of them were female.

The app sent all previously-collected electrocardiograms (ECGs) to the clinic for review.

ECGs obtained within one month of a clinically-ordered echocardiogram were analyzed by AI for an ejection fraction (a measure of the ventricle’s output) less than or equal to 40 percent using a model developed specifically for single-lead ECGs.

Participation was quite high, according to the study authors. During the year of the study, people sent in 125,610 ECGs and 92 percent of them used the app multiple times.

The app detected at least one sinus rhythm (normal heart rhythm) in 421 patients within 30 days of an echocardiogram.

Sixteen people had an ejection fraction less than or equal to 40 percent, meaning that their heart was not pumping well enough.

Thirteen of these 16 were identified using the watch’s AI ECG.

According to Dr. Annabelle Santos Volgman, Professor of Medicine and Senior Attending Physician at Rush Medical College and Rush University Medical Center, the researchers found that the Apple Watch is just as good as a 12-lead ECG that your doctor might do in in his office.

“For detecting atrial fibrillation, it’s very good,” she said, adding, “but it is not good for detecting other problems like heart attacks or heart muscle thickening.”

Dr. Wesley Milks, a cardiologist and Clinical Assistant Professor of Internal Medicine at The Ohio State University Wexner Medical Center, further explained, “A standard diagnostic ECG done in the hospital or clinic is a 12-lead ECG, which is much more detailed in terms of what conditions can be detected.”

Volgman said that she has been using the Apple Watch as a part of caring for her patients for many years now.

“We can document the rhythm that the patient has when they are symptomatic with palpitations. I can reassure them that it is not a worrisome problem when we don’t see any arrhythmias,” she explained.

When problems do show up, she said she can then move on to the next phase of evaluating their risk and what do about their symptoms.

Milks says he often uses Apple Watch data as well.

“For example,” said Milks, “I may ask them to record an ECG tracing when they are having their symptoms or report their heart rate values over time.”

He notes that in addition to performing a single-lead ECG, the Apple Watch is able to monitor heart rate, oxygen saturation, step counts, standing frequency, calories expended, and sleep patterns, which can all be useful information in patient care.

According to study lead author Dr. Paul Friedman, we may now be able to add the detection of a weakened heart to the list, saying that it is “absolutely remarkable that AI transforms a consumer watch ECG signal into a detector of this condition.”

He believes that in the future people may be able to screen for and monitor heart failure in the comfort of their own home simply by using their Apple Watch and an app.

“This holds the opportunity for greater access to care,” said Friedman, “and marked reduction in the cost of some diagnostic testing and research studies…”

He did stress, however, that this research is still in its early stages and will have to be tested and validated before it becomes available to patients.