Dr. Flynn: Explaining what's going on with Charlie McAvoy and his very common heart issue

Charlie McAvoy underwent a procedure today to correct a minor, very common cardiac arrhythmia called supraventricular tachycardia (SVT). There are a few types of SVT, but Bruins team internist Dr. David Finn issued a statement today saying McAvoy’s form of the abnormal heart rhythm is not considered to be dangerous.

Dr. Flynn's BSJ analysis

What's going on: Patients experience episodes of rapid heart rate that are caused by a misfiring of the heart’s electroconductive pathways starting above the lower chambers of the heart (the ventricles). This can happen at any time, but can be brought on by exercise, lack of sleep, caffeine, and other factors.

How it's treated: Sometimes episodes can be “broken” quickly by a patient squatting or other techniques that can help reset the heart’s electrical system. Sometimes episodes can last for hours and require medication to stop. Some patients experience only occasional episodes, once every few months, but others can have multiple episodes per day. If SVT occurs that commonly, medication can be used to try to control the number of episodes.

Another option for some patients is to undergo a procedure called a cardiac ablation. This is the procedure that McAvoy had today. In an ablation, a cardiologist inserts a catheter through the groin and advances it up to the heart. In most types of SVT, heart doctors can find the area of the heart that is misfiring and burn it a small amount with the catheter. If you think that sounds like a dumb idea I completely understand - but it works! The heart function remains normal and the misbehaving cells are no longer able to send the signals that cause the heart to beat rapidly. It's a permanent fix.

Likely outcome: After successful cardiac ablation, athletes can usually return to activity in a few weeks and it sounds like the Bruins expect that McAvoy will return in two. Neither his diagnosis of SVT nor the procedure that was done to correct it should cause any concern that the young Bruin has a weak heart. In fact, I think he’s already reassured you of that in a place that he’d much rather be than in a hospital bed — on the ice.

Dr. Jessica Flynn is a sports medicine physician at Lahey Hospital and Medical Center in Burlington, MA. She writes about injuries in professional sports on her blog, DocFlynn.com. You can follow her on Twitter @jessdeede.

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