Apple has announced that the Apple Watch’s electrocardiogram capability is now live and available as a free software update enabling wrist-based ECGs on the go. Each ECG recording, which is saved in an iPhone app, can be shared as a PDF with physicians, explained Conor Hale in an article in Fierce Biotech.
In addition, the Apple Watch can track a person’s pulse in the background and send the wearer a notification if it senses what might be atrial fibrillation, which is the most common type of irregular heart rhythm. This notification feature also works with heartbeat sensors on earlier versions of the Apple Watch, so the user can be alerted the user if an irregular rhythm is detected five times or more over 65 minutes.
The Apple Watch ECG app is designed for people 22 and up. The app and irregular rhythm notification feature obtained de novo clearances in September. The Centers for Disease Control (CDC) estimated that atrial fibrillation might affect as many as 9 percent of people over 65 in the U.S. and up to 2 percent of younger people.
According to Nancy Brown, CEO of the American Heart Association, “The role that technology plays in allowing patients to capture meaningful data about what’s happening with their heart, right when it’s happening, like the functionality of an on-demand ECG, could be significant in new clinical care models and shared decision making between people and their healthcare providers.”
While using electrodes built into the back of the watch and its crown, the wearer does a circuit while holding it with his or her opposite hand. That enables the watch to send electrical signals across the person’s heart to take a 30-second ECG that is like a single-lead reading. Then the ECG app classifies the heartbeat reading as a normal sinus rhythm, atrial fibrillation or inconclusive. Each recording, which is saved in the iPhone app, can be shared as a PDF with physicians.
As C. Michael Valentine, M.D., president of the American College of Cardiology, said, “The idea that wearables can be used by both patients and their healthcare providers to manage and improve heart health holds promise and should also be approached with caution to ensure information and data are used responsibly and in concert with other evidence-based tools and guidelines.
In a clinical trial with about 600 participants, the ECG app was evaluated by comparing subjects’s sinus rhythms to simultaneous 12-lead ECGs done by a cardiologist, according to Apple. The study determined that the Apple Watch demonstrated 98.3% sensitivity and 99.6% specificity in classifying atrial fibrillation.
In a much larger Apple Heart Study, which screened more than 400,000 participants for atrial fibrillation, the watch’s irregular rhythm background notification feature was evaluated. In a substudy of participants who received notifications, while wearing both the watch and an ECG patch, 80 percent of the subjects demonstrated atrial fibrillation readings on the patch, while 98 percent demonstrated either atrial fibrillations or other arrhythmias.
Sumbul Desai, M.D., Apple’s VP of health, concluded, “We are confident in the ability of these features to help users have more informed conversations with their physicians. With the ECG app and irregular rhythm notification feature, customers can now better understand aspects of their heart health in a more meaningful way.