Keeping hearts beating is Dr. Mark Peterson’s calling.

The Winnipeg-born heart surgeon, who averages more than 250 surgeries per year at St. Michael’s Hospital in Toronto, says despite the long hours, long surgeries and intense professional challenge, he wouldn’t do anything else in the world.

“I feel very lucky to say I love my job — there’s nothing else that I’d rather do. If I won the lottery, I would continue to work because being in the operating room, to me, is not work,” Peterson said.

Peterson says what motivates him most is the desire to continually improve the field of cardiac surgery with new techniques, new approaches and new solutions to old problems.

“There’s always that pressure to make us get better, to innovate. We’re in an era now where things are changing all the time — new imaging techniques and less invasive methods are getting people out of hospital sooner. As technology improves and we get better, people’s expectations get better,” Peterson said.

Peterson has already performed 500 heart surgeries in his two years of practice at St. Michael’s. While the vast majority are pre-planned, carefully orchestrated affairs, he does take on emergency surgeries when needed.

In one particularly memorable case last December, Peterson got a call about an otherwise healthy man in his 50s who was dying from an aortic dissection — the same condition which killed actor John Ritter so suddenly. Peterson raced to the operating room and quickly realized there was no time for a CT scan as the sac around the man’s heart was rapidly filling with blood, threatening to suffocate it.

Once he began surgery, Peterson realized the tear in the man’s heart was much worse than expected, forcing him to make an instant decision to perform a full reconstruction of one of the heart’s main structures (an aortic arch) — an operation which, on a good day, is so complicated that many surgeons don’t perform it.

Peterson went ahead and the operation was so successful, the man left hospital hardly a week later and is doing very well. Moments like that are what convince Peterson he picked the right career.

“We pulled this guy out of the grave. I’m pretty proud about that one. All that culmination of your training and expertise to make somebody better — it’s hard to describe why it’s so satisfying, so rewarding, but it is,” Peterson said.

If the thought of cardiac surgery scares you, maybe it’s time to start living a healthier lifestyle.

“My advice is fairly simple — do everything you can do to avoid having to see me. Quit smoking, eat well and make exercise a mandatory part of your life — it’s ultimately a matter of life and death,” he said.