TORONTO -- Pat Quinn remained hospitalized Wednesday with an irregular heartbeat as the Toronto Maple Leafs prepared to go at least one more game of the Eastern Conference finals without their coach behind the bench.

``He's undergoing more tests and he will remain in the hospital until his heart is in regular rhythm for a long enough period of time that doctors believe it will remain in regular rhythm,'' Maple Leafs president Ken Dryden said Wednesday.

Dryden said Quinn could be released from the hospital as soon as Thursday, but that it's ``highly unlikely'' Quinn will coach Game 4 in Toronto on Thursday night and that he's ``unlikely'' for Game 5 Saturday in Carolina. If a Game 6 is needed on Tuesday night, Dryden said it's ``highly probable'' Quinn would be back.

``As soon as the rhythm becomes stabilized, then basically you can go back and do what you were doing,'' Dryden said doctors informed him.

Dryden said doctors are confident the irregular heartbeat can be addressed with medication, and that Quinn can resume his duties.

Quinn was first diagnosed with the condition Friday, when he underwent tests in Raleigh, N.C. He was allowed to coach in Game 2 on Sunday only after his heartbeat returned to regular rhythm.

The irregular heartbeat returned Tuesday, when Quinn was taken to hospital by ambulance.

``As Pat said to me about an hour ago, he had his first good night's sleep last night, his first good night's sleep in a long time,'' Dryden said.

Assistant coach Rick Ley will remain interim coach until Quinn is able to return.

Carolina leads the best-of-seven series 2-1.

Earlier in the day, Ley said the team would persevere without Quinn, while admitting it's difficult to concentrate on hockey with his friend in the hospital.

``That's the hard part of it,'' Ley said. ``When a good friend, my boss, our coach isn't doing great, that obviously is on everybody's mind. We're worried about him.

``And I know for a fact, our players -- maybe it was a little bit of a distraction because they are worried about him.''

Quinn has had trouble sleeping and complained about experiencing shortness of breath over the past week.

It has been a long season already for Quinn, who doubles as the Maple Leafs' general manager. Quinn also coached in the NHL All-Star game in February and coached Canada to the gold medal in the Olympics.

Dryden said now is not the time to address questions of whether to lighten Quinn's workload.

``I would suspect the first person that would say that this is a discussion for another time would be Pat,'' Dryden said. ``There will be a time when that becomes more of a priority conversation. Right now it isn't.''

Ley said Quinn has been under pressure as the Maple Leafs have survived two grueling seven-game series already.

``I think we all look upon this year to see what Pat's gone through physically and emotionally,'' Ley said. ``He's been under the gun since the opening of training camp. And we were concerned because he wasn't sleeping well.''

Ley, a longtime Quinn associate, has previously been head coach of the then-Hartford Whalers and, more recently, the Vancouver Canucks in the mid-1990s.

``Pat's last thing was do things the way you would do them,'' Ley said of the advice Quinn gave him. ``I'm not going to bother him with hockey matters at this time. But if he wants to pass something on, certainly, he's the boss.''

Leafs enforcer Tie Domi said he's concerned about Quinn.

``Health is a lot bigger than the game,'' Domi said. ``We've been through adversity all year. Who knows what the prognosis is. We don't know anything yet. Hopefully, he'll be back.''

Added center Alyn McCauley: ``Don't worry about us, we'll be fine.''