Apple Watch ECG Saved Man From “Silent" Atrial Fibrillation Heart Condition

Ed Dentel was chasing his seven-year-old daughter around the slides at Pennsylvania’s Great Wolf Lodge water park when his heart started pounding. The 46-year-old taekwondo enthusiast from outside Richmond, Virginia wasn’t feeling quite like himself in the days before Thanksgiving, but he wrote it off at the time. His watch would later tell him that his heart was trying to send him a message.

Weeks after Dentel returned from the Great Wolf Lodge, Apple released an update to his Apple Watch that would change his life. The update allowed Apple Watch Series 4 users to take an electrocardiogram — a medical grade heart rate reading — and run it through an algorithm that detects atrial fibrillation, a potentially disastrous fluttering of the heart.

In Afib, as its commonly known, the electrical signals that usually travel methodically through the heart muscle start to travel randomly, leading to heart arrhythmia. Left untreated, this erratic beating can later cause heart disease and stroke. Dentel wasn’t thinking about Apple’s new ECG feature when he updated his watch that past weekend — he actually thought the feature was “useless” — but when he did, the watch diagnosed him with Afib so quickly that he thought it was a glitch.

"Ah, first release glitches, whatever.

“The first thought that went through my mind was ‘Ah, first release glitches, whatever’,” he tells Inverse. “And I just shut it down, turned it off, and put it on the nightstand for the night.”

One day later, a cardiologist confirmed the watch’s diagnosis. Some doctors think there could be a lot more people out there like Dentel, living riskily with “silent Afib,” a condition they don’t even know they have.

Silent But Potentially Deadly

Over a healthy breakfast of Cheerios and Wheat Chex the morning after the update, Dentel wondered about his watch’s diagnosis. On his wife’s wrist, the watch gave a normal reading. But when he put it back on, the Afib diagnosis returned. “My wife was standing there looking at me, we thought there was something going on,” he says.

Dentel is not an Iron Man athlete, but he works out in his basement gym, bikes, and skis. Not in a million years would he imagine having a heart condition. But Dr. Peter Kowey, a cardiologist at Main Line Health’s Lankenau Heart Institute, thinks there are probably lots of people out there like Dentel living with silent Afib. Because it’s symptomless — the bigger issues are the problems it causes later — cardiologists struggle to pin a number on how common it is.

“You’ll hear people talk about one to three percent of the population,” Kowey tells Inverse. “I think this is a gross underestimation because there are a lot of people walking around who aren’t aware that they have the arrythmia. Most of us believe that the prevalence of the disease is higher.”

Kowey, who advised on the Apple Heart Study — the FDA-approved clinical trial that produced the Apple Watch’s ECG — guesses that if you make it to the age of 40, there’s a one in four chance of developing Afib before you die, at least in the United States.

“Do You Have Apple Stock?”

When Dentel arrived at the urgent care clinic for advice, he suddenly felt foolish asking for help. “It just runs through your head how stupid you’re going to sound, saying, ‘My watch is telling me I have heart problems. No, I don’t feel it myself. Could you check me out?’”

But telling his story to the nurse at the clinic, he was quickly ushered to the front of the line. Within a few minutes, he was hooked up to a traditional 12-lead ECG in the presence of a cardiologist, who quickly confirmed what roughly 85 different notifications from his watch had suggested.

“He asked, ‘Do you have Apple Stock?’” Dentel recalls. “He said, ‘You ought to buy some, I think they just saved your life.’”

Kowey agrees. “Without diagnosis, if he were to go on with that, his life would have been shortened,” he says.

Did It Actually Save His Life?

There will very likely be more Apple Watch users diagnosed with Afib in the near future. For those people, says Kowey, that can mean either of two things.

Some patients with Afib have extremely high heart rates — somewhere in the 130 to 140 range when they’re just walking around. Working at that high capacity all the time can cause heart failure over time.

There’s also increasing evidence that Afib can be responsible for stroke later in life. The electrical signals that control heartbeat are unpredictable in Afib patients, which can change the way blood moves through the heart. In some of these patients, blood can actually form a clot in the left atrial appendage, a tiny sac attached to the heart’s upper left chamber. When this happens, says Kowey, it can cause a serious and often debilitating stroke.

“So, we’re not talking little strokes. We’re talking about big ones.” Kowey says. “And when that happens, people are disabled and they don’t frequently do well.

A diagnosis of Afib allows people to pursue interventions to prevent heart failure and stroke, like increasing exercise, making lifestyle changes, improving diet, and taking medication.

These days, Dentel still feels fine, though since his doctor confirmed the Apple Watch’s diagnosis, he’s begun a course of Dilitiazem, a blood pressure drug. While the diagnosis hasn’t changed his present, it will almost definitely shape his future: He has plans for the upcoming year and doesn’t have time to let Afib to slow him down. In April, his entire family will try to earn their blackbelt qualifications in taekwondo, and he’s already eager to get out on the bike with his daughter this spring and in the years to come.

“We chose to have a little girl a little later in life,” he says. “So I’d really like to stay active and keep up with her going all throughout high school.