BOSTON — By this point in the season, nearly every hockey player and his teammate is dealing with a bump or bruise, sprain or strain, maybe even a break. Injured bones and joints — minor to major — are part of the territory.

A heart condition is something else entirely.

Bruins defenseman Charlie McAvoy’s abnormal heart rhythm, although treated successfully on Monday at Massachusetts General Hospital, was sobering news for his teammates — especially fellow defenseman Matt Grzelcyk, a second-year captain at Boston University when McAvoy arrived in 2015-16.

“It’s tough seeing him have to go through that,” Grzelcyk said of McAvoy, with whom he swapped text messages after Monday’s procedure called a catheter ablation to treat a condition called supraventricular tachycardia, or SVT, in which the heart suddenly beats fast when a person isn't exercising or under stress.

“He’s been one of my closest friends for a while now. It’s a little more scary when it’s the heart, as opposed to it being an injury like a shoulder or knee.”

McAvoy, a top-pairing defenseman with B’s captain Zdeno Chara and one of the NHL’s most impressive rookies, first reported symptoms after a Nov. 26 game against the Edmonton Oilers.

An evaluation by team physicians revealed SVT, which, according to a statement from team internist Dr. David Finn, “is not considered to be dangerous to his health, but can recur at anytime and causes significant symptoms.”

McAvoy, who “was cleared to play by the medical team and was monitored closely,” per Dr. Finn’s statement, played through Saturday night’s 4-1 win at Montreal — a span of 24 games — before electing to undergo Monday’s ablation.

Bruins coach Bruce Cassidy said he felt comfortable using McAvoy, whose average ice time of 22 minutes, 48 seconds per game ranks second to Chara, as he normally would.

“No, it’s not going through my head (during games),” Cassidy said. “It was up to Charlie, his parents, and medical staff: ‘When do we need to deal with this?’ That’s a decision they made.”

McAvoy, who is expected to need two weeks to recover from the procedure, was “doing terrific” on Tuesday, according to reports Cassidy got from Bruins general manager Don Sweeney. Grzelcyk received the same messages.

“He’s in good spirits. He’s doing well,” Grzelcyk said. “I just wanted to make sure he’s doing well, and not too down on himself or anything like that. I think he’s doing fine. I know he’s healthy. Two weeks off, and we’ll see where it goes from there … It’s tough, but I think he’ll come out stronger for it.”

Good as new

Meanwhile, Hingham native Brian Boyle, diagnosed with chronic myeloid leukemia after arriving at his first training camp with the New Jersey Devils in September, came to TD Garden for his only scheduled hometown appearance of the season with 11 goals — third-best on the team’s scoring list — despite missing the first 11 games of the season to begin treatment.

“I’ve been feeling pretty good,” said Boyle, who signed a two-year contract at $2.75 million per season as an unrestricted free agent on July 1. “I’ve been feeling even better, since the treatments have kicked in.”

Boyle’s medication is administered in pill form.

The 33-year-old center, who finished last season with the Toronto Maple Leafs after being traded by the Tampa Lightning, was unable to participate in training camp, and didn’t play his first game with his new team until Nov. 1. Tuesday’s game against the Bruins was his 37th in a row, and the 6-foot-6, 245-pounder was looking to snap a six-game scoring drought.

“I’ve had numerous chances in the last 10, 12 games, and they haven’t gone in like they were in the beginning,” he said. “That’s the way it goes sometimes, but you always want to be consistent.”

Around the Boards

Braintree’s Brian Gibbons, who put up 12 goals and 23 points over 45 games for the Devils after spending the previous two seasons in the AHL, missed his second game with a broken thumb sustained on Saturday at Philadelphia. Gibbons’ absence opened the door for former Bruin Jimmy Hayes, who was scratched for 13 straight games until Gibbons got hurt … With McAvoy sidelined for the first time, defensemen Chara and Brandon Carlo and forwards David Pastrnak, Tim Schaller and David Pastrnak are the only Bruins to have played all 46 games. Center Riley Nash’s only missed game — Dec. 21, against the Winnipeg Jets — was due to illness, not injury.