New Apple Watch: Do You Have Atrial Fibrillation?

Apple has just released its latest Apple Watch, and this one comes with the ability to perform an electrocardiogram on its wearer. That’s an amazing leap in technology, and can give users a lot of new information about their health, but Robbie Gonzalez, writing at WIRED, suggests that unless you have atrial fibrillation, the feature could do more harm than good. He writes (abridged):

Healthcare providers usually use ECGs in hospitals to measure the heart’s electrical activity and detect abnormalities in its rhythm. But with the latest iteration of its smartwatch, Apple wants to put an ECG on your wrist that you can use “anytime, anywhere.”

It sounds like a great idea in theory. Even Ivor Benjamin, president of the American Heart Association, showed up to give Apple props. “The AHA is a relentless force for a world of longer, healthier lives,” Benjamin said on stage Wednesday. “Products that seek to provide deeper health insights, like the Apple Watch Series 4, offer great potential in getting us there.”

People with atrial fibrillation, which the CDC estimates affects between 2.7 and 6.1 million Americans, could likely benefit from a wearable, on-demand ECG device like the new Apple Watch. (AFib is the most common arrhythmia, and the only kind Apple’s watch is approved to detect.) But for everyone else, evidence suggests the potential costs could actually outweigh the proposed benefits. Despite what Benjamin says, there is such a thing as too much insight into one’s health.

The question of ECG’s usefulness as a screening tool is older than you probably realize. When they first came on the scene, physicians used them to screen patients with known or suspected heart issues. It wasn’t long before healthcare providers starting using them to examine patients with no symptoms or family history of cardiovascular illness.

There’s no exact numbers on how common preventive ECG screening is in the US, but according to a recent editorial in the Journal of American Medicine, ECG examinations of asymptomatic patients had become regular features of annual physicals by the early aughts—until professional societies ran cost/benefit analyses on the practice and started advising against it.

One of those societies was the US Preventive Services Task Force. An independent, volunteer panel of national experts in disease prevention and evidence-based medicine, the task force has been issuing recommendations on the value of electrocardiography screening for more than a decade. In 2004, the panel reached no firm conclusion on the value of using ECG to screen for heart disease in asymptomatic adults, citing a lack of studies on patient outcomes. But by 2012, it had revised its statement, recommending against ECG screening in asymptomatic adults at low risk for heart disease.

In 2018, the group revisited the matter yet again, but its assessment stayed the same. “The USPSTF recommends against screening for cardiovascular disease with resting or exercise ECG in adults at low risk of cardiovascular disease events,” the panel wrote in its latest statement, which appeared in JAMA this past June.

As for screening asymptomatic adults at high- or intermediate-risk of heart disease, the task force says there’s insufficient evidence. And in a separate statement published in JAMA just last month, the panel had the same to say about ECG screening for atrial fibrillation, specifically.

Read more here.