Use of an Apple Watch for heart rhythm monitoring was feasible and picked up more arrhythmias than a standard patch monitor in a pediatric population, a prospective study showed.

Among 107 children and teens aged 6-18 years with symptomatic palpitations wearing both devices for 2 weeks, the Apple Watch captured arrhythmias in twice as many patients as the Zio patch rhythm monitor (48% vs 19%, P < .0001).

And perhaps not unexpectedly, kids were good with the devices, Scott Ceresnak, MD, of Stanford University School of Medicine in Stanford, California, reported at the Heart Rhythm Society (HRS) 2026 meeting in Chicago.

Overall, 79% of the ECG tracings recorded by the smartwatch during episodes of tachyarrhythmia were also deemed reliably interpretable.

“Palpitations are one of the most common reasons for referral to pediatric cardiology,” Ceresnak said, noting that the different monitors and tools available to capture single-lead ECGs during symptomatic episodes have inherent limitations and challenges. “[T]here remains a need for more practical, noninvasive extended cardiac rhythm monitoring in children.”

The device’s atrial fibrillation (AF) functionalities are cleared only for users aged 22 years or older, and its algorithms were developed and validated in adult populations.

Still, in the children using it in the study setting, the device’s algorithm correctly identified AF in 73% of ECGs and correctly flagged supraventricular tachycardia as a “high heart rate” in 75% of cases.

The Pediatric Apple Watch Study included 107 patients (average age, 14 years; 62% girls) undergoing outpatient evaluation for heart palpitations at a single healthcare system. In addition to an ambulatory patch rhythm monitor for the first 2 weeks, participants also received an Apple Watch (version 5 or later) for 6 months with instructions to press the patch first and then record an ECG with the Watch whenever they experienced arrhythmia symptoms.

Blinded pediatric electrophysiologists reviewed the ECG tracings, device-generated diagnoses, and tracing quality. They found a high correlation between the two devices for heart rate (correlation coefficient, 0.92).

The device automatically transmitted recordings to a secure digital platform, without the data being shared with the care management team.

“We’re still at the point where if the patient has symptoms, they need to be seen by their pediatrician. The pediatrician would evaluate and say, ‘Do you need to see a cardiologist or not?’ But in the meantime, while you’re sort of waiting to see the doctor, if you have a Watch, you could record an ECG, and then you can bring it and show your doctor and have more of an advanced discussion about it,” Ceresnak told Medscape Medical News.

“There’s particular promise in catching arrhythmias that are too sporadic for the typical 2 weeks of patch monitoring to pick up,” said Shankar Baskar, MD, electrophysiologist at Cincinnati Children’s Hospital in Cincinnati, who was not involved in the study.

“One of the big challenges in pediatric cardiology or EP [ electrophysiology] is that children sometimes feel symptoms when they’re not actively being monitored, and these symptoms can happen very infrequently — once in 3 months, once in 6 months,” he said in an interview. “A device that helps families capture an ECG at that moment is going to meaningfully improve the diagnosis and help us treat them better.”

But there’s also the potential for some harm. Session chair Graham Peigh, MD, of Northwestern University in Chicago, pointed to concerns about screening with wearable devices based on adult studies.

“We know, at least in adult populations, that in some studies, having access to digital health tools to record a single-lead ECG can alleviate health-related anxiety; in other cases, it enhances health-related anxiety,” he said at the session.

In asymptomatic children, Ceresnak told Medscape Medical News: “The likelihood that the Watch with current adult algorithms picks up something that is going to be a serious health concern for a child is less likely at baseline, whereas in the adult population, AF in an asymptomatic patient can still be really worrisome and damaging and dangerous.”

For symptomatic children, the Watch’s automated classification algorithm had a sensitivity and a positive predictive value for normal sinus rhythm of about 85% but a specificity and a negative predictive value below 50%, as compared with physician reading. It had a negative predictive value and a specificity for AF over 98% but a sensitivity of 73% and a positive predictive value of 48%.

But the adult-trained algorithm wasn’t so good at many common pediatric arrhythmias, flagging them as inconclusive. Ectopic atrial tachycardia, in particular, was labeled as sinus rhythm in 70% of cases.

“If you get one of those abnormal rhythms, we don’t really exactly know, for each individual patient, how accurate that is,” Ceresnak said.

The study didn’t break down the events that differed between the patch and the Watch during the concurrent period and those caught after patch monitoring ended, Baskar noted.

Developing pediatric-specific algorithms and classification criteria might help, Ceresnak said, but meanwhile, it would be useful to clinicians for the device companies to work with the FDA to open up the heart-monitoring functionalities to children.

“My hope is that even giving access to the ECG feature and opening up access could be helpful,” he said. “We know 8-year-olds can use the Watch. They can get good quality tracings….Even if it’s not automated algorithms that can classify and detect an arrhythmia, if it’s just access to the ECG feature so they can obtain an ECG during symptoms, that would be a major step.”

The study was sponsored by the Apple Investigator Support Program, the Stanford Center for Biodesign, the Stanford Center for Digital Health, and the Adult Congenital Heart Association.

Ceresnak and Baskar disclosed having no relevant relationships with industry.

Peigh disclosed having relationships with Medtronic and Philips.

Crystal Phend is an award-winning medical journalist with decades of experience reporting on clinical research and healthcare developments across specialties. When not walking the halls of a medical conference, she can be found at a keyboard in upstate New York.