In an interview with the Telegraph last week, four-time major champion Rory McIlroy said that a viral infection he contracted 18 months ago in China resulted in thickening of the left ventricle in his heart.
“There’s a bit of scar tissue,” McIlroy said.
McIlroy also said he has a “flat T-wave,” which is not the same as a flat takeaway.
There is no cause for concern, McIlroy stressed; it’s just something he’ll need to keep an eye on.
Still, as word of McIIroy’s condition spread, so did curiosity among armchair cardiologists. How common is the condition? How serious? And what impact might it have on his health and play?
According to Dr. Gordon Tomaselli, the chief of the Johns Hopkins Division of Cardiology and former president of the American Heart Association, viral infections like the kind described by McIlroy are not uncommon.
How often they cause scarring is impossible to say, because not all patients undergo scanning to test for that result. 
The implications for patients vary, depending on the severity and extent of scarring. In some cases, scarring can predispose a person to heart disease, or reduce their tolerance for vigorous exercise.
But, Dr. Tomaselli said, scarring can also be so minimal as to pose “very little to no risk at all.”
Dr. Tomaselli emphasized that he could not comment specifically on McIlroy’s case. But based on what has been revealed so far, he seconded what McIlroy himself has said: It doesn’t sound like a cause for serious worry.
“There is a very broad spectrum of what could be wrong,” Dr. Tomaselli said. “But reading between the lines from what has been reported and what [McIlroy] has described, it sounds likely that this is something that will just need to be monitored and will not have any effect on his play.”
As for a T-wave, the heart has an electrical cycle that moves in waves through the upper chambers, or atria, then through the lower chambers, or ventricles. The T-wave is the final wave of that cycle, representing the return of the ventricles to a resting state.
A flat T-wave can result from a number of factors, including low potassium in the blood stream. It may indicate that the heart is low on oxygen. But in the absence of other symptoms, a flat T-wave doesn’t tell us much. In other words, there’s seemingly not much to fret here, folks. You can go back to worrying about Rory’s putting stroke.
