Wearables: Smartwatches May Detect Abnormal Heart Rhythms

Findings from this study come from a survey of electronic medical records for pediatric cardiology patients getting care at Stanford Medicine Children 's Health. During a four-year period, patient medical records from 2018 to 2022 mentioned “Apple Watch” 145 times, among those mentioning the wearable 41 had abnormal heart rhythms that were confirmed by traditional diagnostics, and of these 29 had their arrhythmias diagnosed for the first time. 

"I was surprised by how often our standard monitoring didn't pick up arrythmias and the watch did," said senior study author Scott Ceresnak, MD, professor of pediatrics. Ceresnak is a pediatric cardiologist who treats patients at Stanford Medicine. "It's awesome to see that newer technology can really make a difference in how we're able to care for patients."

While most of the abnormal rhythms detected were not life-threatening, the arrhythmias detected can cause distressing symptoms such as a racing heartbeat, dizziness, and fainting. When it comes to diagnosing children’s cardiac arrhythmias/abnormalities doctors face a few challenges. Cardiac diagnostics, despite advances, still are not ideal for children. Although monitors are smaller, more comfortable, and can be worn longer they sometimes fall off early or cause problems like skin irritation from the adhesives. Another problem is that even a few weeks of continuous monitoring may not be able to capture the heart’s erratic behaviors, especially in children. Children can experience arrhythmias unpredictably; they may go months between episodes making it even harder to determine what is happening. 

Data from the wearables included alerts about heart rates and patient-initiated electrocardiograms/ECGs from an app that used the electrical sensors in the smartwatch. When the app is activated, the ECG functions record the heart’s electrical signals, and physicians can then use the pattern of electrical pulses to help diagnose different types of possible heart problems. 

Wearables may be able to assist with monitoring, although it is still not perfect. Using this technology to measure a child’s heart rhythm is limited by the fact that existing smartwatch technology and algorithms that detect heart problems have yet to be optimized for children. The most notable differences are that children tend to have faster heartbeats than adults, and they also tend to experience different types of abnormal rhythms than adults with cardiac arrhythmia. 

According to the authors, led by the lead author Aydin Zahedivash, MD, a clinical instructor in pediatrics, the paper showed that the smartwatches appeared to help detect arrhythmias in children, suggesting that it would be useful to design versions of the wearable technology and algorithms based on real-world heart rhythm data from children. 

From the 145 mentions of smartwatches in the records, 41 had arrhythmias confirmed, of these 18 had collected an ECG with their wearable, and 23 had received notifications from their devices about a high heart rate. The information from the devices prompted the children’s physicians to conduct medical workups that resulted in 29 children receiving new diagnoses, including 10 patients receiving a smartwatch diagnosed arrhythmia that traditional monitoring methods never picked up (The information from the watch confirmed suspicion of supraventricular tachycardia). Additionally, smartwatch use noted in 73 patients’ medical records did not lead to the diagnosis of arrhythmias. 

"These irregular heartbeats are not life-threatening, but they make kids feel terrible," Ceresnak said. "They can be a problem and they're scary, and if wearable devices can help us get to the bottom of what this arrythmia is, that's super helpful."

In many cases of supraventricular tachycardia, the abnormal heart rhythm is caused by a small short-circuit in the heart's electrical circuitry, but this can often be cured with a medical procedure called catheter ablation that destroys a small, precisely targeted region of heart cells causing the short circuit.

"A lot of kids have palpitations, a feeling of funny heartbeats, but the vast majority don't have medically significant arrythmias," Ceresnak said. "In the future, I think this technology may help us rule out anything serious."

"The wearable market is exploding, and our kids are going to use them," Ceresnak said. "We want to make sure the data we get from these devices is reliable and accurate for children. Down the road, we'd love to help develop pediatric-specific algorithms for monitoring heart rhythm."

It was noted that “this study was conducted without external funding. Apple was not involved in the work.” However, “Apple's Investigator Support Program has agreed to donate watches for the next phase of the research which is open only to children who are already cardiology patients at Stanford Medicine Children's Health to further assess the utility of the Apple Watch for detecting children's heart problems. The study will measure whether, in kids, heart rate and heart rhythm measurements from the watches match measurements from standard diagnostic devices.”