Twin brothers Shane, left, and Shawn underwent heart surgery at the Royal Alexandra Hospital on the same day. (Perry Mah, QMI Agency)

EDMONTON - Identical twins Shawn and Shane Mamer will set off airport security alarms for the rest of their lives.

And explosive-type sports activities such as hockey and football are out of the question for the athletic 31-year-olds.

But since having hockey puck-size defibrillators surgically implanted in their chests Friday at Royal Alexandra Hospital, the brothers no longer have to fret about their hearts suddenly stopping.

"We don't have to worry about dying on a daily basis," Shane said from their hospital room, just hours after undergoing surgery.

"It gives you a second chance at life -- and third and fourth and fifth."

Both Shawn and Shane, Saskatoon residents, have a relatively rare heart-muscle condition known as arrhythmogenic right ventricular cardiomyopathy.

In their case, muscle on the right sides of their hearts is being replaced by fat, explained Dr. Evan Lockwood, a cardiac electrophysiologist.

The siblings have each developed a simple arrhythmia, characterized by the feeling that their hearts are skipping a beat, Lockwood said.

But the condition worsens over time.

When they eventually develop a life-threatening arrhythmia, their defibrillators will kick in, giving them a shock to reset their heart rhythms.

"It's like the paddles that you see on ER shows, but its implanted right in your chest," Shane explained.

"The instant that our heart goes into fibrillation for the first time, and it will, and this defibrillator kicks in, basically from that point on is when we shouldn't have been alive."

The defibrillator implant, which is also done at the Mazankowski Alberta Heart Institute, is essentially a tiny computer that monitors the patient's heartbeat.

It takes five to 12 seconds to charge up and deliver a shock.

"So some people will pass out before they get the shock," Lockwood said. "And the shocks are painful. But if you feel the shock, you're not dead."

The batteries have to be changed every five to eight years.

Its pretty fancy technology," Lockwood said.

"Every six months, they seem to get smaller, last longer and get smarter."

The Mamers' heart condition is hereditary and occurs in one in 2,000 to one in 5,000 people in the general population, Lockwood said.

There's a 50-50 chance of passing it to offspring. The twins got theirs from their mother. Each brother has two young children, who are expected to be tested by the time they turn 10.

Undiagnosed, the condition is a "serious killer," Lockwood said.

The median age of death in men is 41, compared to 71 in women, he said.

The condition is especially prevalent in Newfoundland and Italy.

In Newfoundland, where the condition shows up in at least 15 families, it has "spread like wildfire," Lockwood said.

With Alberta's high population of Newfoundlanders in the oilsands, doctors are hoping to sound the alarm across the province.

"We're getting a lot more referrals here for this condition than other places in the country," Lockwood said, noting doctors are now on the lookout for patients, especially young men, with palpitations.

They're currently seeing about two cases a month, compared to about two cases a year prior to the boom.

"Not a lot of people know about this disease," added Shawn, the older sibling by 10 minutes. "If anybody's having palpitations or has a history of early death in their families, they need to look into it."

The brothers, both training to be dentists, were originally slated for the surgery in mid-February, but were forced to reschedule because they were writing their board exams.

They were diagnosed last year, shortly after their uncle died of the heart condition at 48.

Fast facts

* Early symptoms of arrhythmogenic right ventricular cardiomyopathy include heart palpitations.

* The heart condition is hereditary.

* It's especially prevalent among Newfoundlanders and Italians.

* There are six cardiac electrophysiologists in Edmonton, split between the Royal Alexandra hospital and the Mazankowski Alberta Heart Institute, who treat the condition.

* An implanted defibrillator acts as insurance but doesn't cure the condition.

* The only cure is a heart transplant.

cary.castagna@sunmedia.ca