Smartwatches can detect abnormal heart rhythms in children, study finds

Smartwatches can help doctors detect and diagnose irregular heart rhythms in children, according to a new study from the Stanford School of Medicine.

The finding comes from an investigation of electronic medical records of pediatric cardiology patients receiving care at Stanford Medicine Children’s Health. The study will be published online on December 13 in Communications medicine.

Over a four-year period, patients’ medical records mentioned “Apple Watch” 145 times. Among the patients whose medical records mentioned the smartwatch, 41 had abnormal heart rhythms confirmed by traditional diagnostic methods; among them, 29 children had their arrhythmias diagnosed for the first time.

“I was surprised by how often our standard monitoring didn’t detect arrhythmias, but the watch did,” said the study’s lead author, Scott Ceresnak, MD, professor of pediatrics. Ceresnak is a pediatric cardiologist who treats patients at Stanford Medicine. “It’s great to see that new technologies can really make a difference in how we can care for patients.”

The lead author of the study is Aydin Zahedivash, MD, clinical instructor in pediatrics.

Most of the abnormal rhythms detected were not life-threatening, Ceresnak said. However, he added that detected arrhythmias can cause distressing symptoms such as rapid heartbeat, dizziness and fainting.

Skip a beat, sometimes

Doctors face two challenges when diagnosing cardiac arrhythmias, or heart rhythm abnormalities, in children.

The first is that cardiac diagnostic devices, although they have improved in recent years, are still not ideal for children. Ten to twenty years ago, a child had to wear a Holter monitor for 24 to 48 hours, consisting of a device the size of a smartphone connected by wires to five electrodes glued to the child’s chest. Patients can now wear event monitors, in the form of a single sticker placed on the chest, for a few weeks. Although event monitors are more comfortable and can be worn longer than a Holter monitor, they sometimes fall off prematurely or cause problems such as skin irritation from adhesives.

The second challenge is that even a few weeks of continuous monitoring may not detect the heart’s irregular behavior, because children experience arrhythmias unpredictably. Children can go months between episodes, making it difficult for their doctors to determine what is happening.

Connor Heinz and his family faced both challenges when he experienced periods of increased heart rate starting at age 12: an adhesive monitor was too itchy and he had irregular heart rhythms. only once every few months. Ceresnak thought he knew what was causing the racing rhythms, but he wanted confirmation. He suggested that Connor and his mother, Amy Heinz, could try using Amy’s smart watch to record the rhythm the next time Connor’s heart started racing.

The use of smartwatches to measure children’s heart rates is limited by the fact that existing algorithms in smartwatches that detect heart problems have not been optimized for children. Children have faster heartbeats than adults; they also tend to have different types of abnormal rhythms compared to adults with cardiac arrhythmias.

The paper shows that smartwatches appear to help detect arrhythmias in children, suggesting that it would be useful to design versions of smartwatch algorithms based on real data about children’s heart rates.

Evaluation of medical records

Researchers searched patients’ electronic medical records from 2018 to 2022 for the phrase “Apple Watch,” then checked which patients with that phrase in their records had submitted smartwatch data and been diagnosed with cardiac arrhythmia.

Data from the watches included alerts about patients’ heart rates and patient-triggered electrocardiograms, or ECGs, from an app that uses the watch’s electrical sensors. When patients activate the app, the ECG function records electrical signals from the heart; Doctors can use this pattern of electrical pulses to diagnose different types of heart problems.

Of 145 mentions of the smart watch in patient records, 41 patients had confirmed arrhythmias. Among them, 18 patients had performed an ECG with their watch and 23 patients had received a notification from the watch regarding an elevated heart rate.

The information provided by the smart watches prompted the children’s doctors to conduct medical examinations, from which 29 children received new diagnoses of arrhythmia. In 10 patients, the smartwatch diagnosed arrhythmias that traditional monitoring methods had never detected.

One of these patients was Connor Heinz.

“At a basketball tryout, he had another episode,” Amy Heinz recalled. “I put the watch on him and emailed a bunch of captures (of his heartbeat) to Dr. Ceresnak.” Information from the watch confirmed Ceresnak’s suspicions that Connor was suffering from supraventricular tachycardia.

Most children with arrhythmia suffered from the same problem as Connor, which was a racing heartbeat coming from the upper chambers of the heart.

“These irregular heartbeats are not life-threatening, but they make children feel very bad,” Ceresnak said. “They can be a problem and they’re scary, and if wearable devices can help us understand what that arrhythmia is, that’s very helpful.”

In many cases of supraventricular tachycardia, the abnormal heart rhythm is caused by a small short circuit in the heart’s electrical circuits. The problem can often be resolved by a medical procedure called catheter ablation that destroys a small, precisely targeted region of heart cells, causing the heart to short out.

Now 15, Connor has been successfully treated with catheter ablation and plays basketball for his high school team in Menlo Park, California.

The study also found that smartwatch use was noted in the medical records of 73 patients who were ultimately not diagnosed with an arrhythmia.

“A lot of kids have palpitations, weird heartbeats, but the vast majority don’t have medically significant arrhythmias,” Ceresnak said. “In the future, I think this technology could help us rule out any serious hypotheses.”

A new study

The Stanford Medicine research team plans to conduct a study to further evaluate the usefulness of the Apple Watch in detecting heart problems in children. The study will measure whether, in children, heart rate and heart rate measurements from watches match measurements from standard diagnostic devices.

The study is open only to children who are already cardiology patients at Stanford Medicine Children’s Health.

“The wearables market is exploding and our kids are going to use them,” Ceresnak said. “We want to ensure that the data we get from these devices is reliable and accurate for children. In the future, we would be happy to help develop pediatric-specific algorithms to monitor heart rate.”

The study was conducted without external funding. Apple was not involved in the work. Apple’s Investigator Support Program has agreed to donate watches for the next phase of research.

Apple’s Irregular Rhythm Notification and ECG app is cleared by the Food and Drug Administration for use by individuals 22 years of age or older. High heart rate notification is only available to users aged 13 or older.