An Edmonton-area man is crediting his smartwatch with alerting him to a heart attack he didn’t realize he was having.

Dennis Anselmo, a 62-year-old from Morinville, Alta., bought an Apple Watch back in August to add to his current collection of 35 watches. Two weeks later, he started to feel sick while building a fence.

“I just started feeling really, really terrible, with flu-like symptoms – hot and cold, sweating, jittery – to the point that I said to my helper, ‘I’ve just got to sit down and see if this is going to go away’," he told CTV News Channel.

Sitting down to catch his breath, he decided to check his heart rate using an app on his watch.

"When I flipped it up, it came up at 210 beats per minute," he said, noting his normal resting heart pulse was 60 beats per minute.

“I said, ‘I think I better call 911,” he remembered.

An ambulance rushed Anselmo to Edmonton’s Royal Alexandra Hospital where he learned he was having a heart attack.

Doctors found that a large artery in his heart was nearly 70 per cent clogged. After they repaired the blood vessel, they told Anselmo he had atrial fibrillation, a form of irregular heart rhythm.

High blood pressure, heart disease, or diabetes all raise the risk for AF, which affects about 350,000 Canadians and can lead to strokes and heart attacks.

Anselmo says he’s glad he had the watch, because he would not have realized he was having a heart attack otherwise.

“I always thought if you’re having a heart attack, you’re going to get the pain in your arm or tightness in your chest. I didn’t experience any of that. …I thought I had the flu,” he said.

Doctors told Anselmo that if he hadn't called 911 and had just laid down as he thinks he probably would have, his symptoms would likely have worsened, leading to a possible stroke or another heart attack.

“The doctors told me that’s usually when you have a second heart attack. That one can do a lot more damage or even kill you,” he said.

Anselmo decided to tell his story to an Apple store employee, who passed it on to others at Apple headquarters. There, officials arranged interviews with newspapers in the U.K. and China, and now, his story is spreading across the globe.

With a report from CTV Edmonton