Tennis star Mardy Fish has battled a much scarier opponent than Novak Djokovic or Rafael Nadal this spring – his own heart. The highest-ranking American player is recovering from a cardiac catheter ablation he underwent last week at Cedars-Sinai Hospital in Los Angeles.

For months Fish had been experiencing heart palpitations, or sensations that his heart was racing, that would wake him up in the middle of many nights. “It was like my heart was going to jump out of my chest,” the world’s tenth-ranked player explained. Even when he wasn’t having palpitations, he frequently lost sleep, not knowing when they would occur again or what would trigger them.

In an interview with USA Today recently, Fish described how the attacks affected his game and his life. “During days, I’m totally fine. I can track it and work out fine. But every time I would go to bed my mind would start racing. Is this going to happen tonight? Is this going to be another night like that? It was super hard to go to sleep.”

Dr. Marcus Wharton, an arrhythmia specialist and Director of Cardiac Electrophysiology at the Medical University of South Carolina, claims that these sensations and fears are common. While not knowing the exact medical circumstances in this case, he suggests that these symptoms appear to be consistent with supraventricular tachycardia (SVT).

SVT is a surprisingly common heart condition, affecting approximately 1 in 1000 people in the general population, including elite athletes. Wharton describes it in layman’s terms as small areas within the heart which generate abnormal electrical signals to create an abnormal heart rhythm.

Part of the challenge with these anomalies is to properly make the diagnosis. The heart will beat normally the vast majority of the time. While athletes can sometimes trigger these palpitations with exertion in sports and exercise, they can often occur only at rest, as Fish’s symptoms seemed to do. Patients can wear monitors that record heart rhythms to help detect the problem, but Dr. Wharton points out that these conditions occasionally escape detection with these devices.

After an episode one night during the Sony Ericsson Open in Key Biscayne, Florida where his heart pounded and raced as fast as 180 beats per minute, he called 911 and went to a local hospital. He saw several doctors and even tried wearing such a heart monitor. When no specific problem could be isolated, Fish underwent more aggressive diagnosis and treatment.

Dr. Wharton explains that doctors pace the heart through catheters to induce the abnormal rhythm while they closely monitor the electrical activity of all areas of the heart. When they find the faulty tissue, they can ablate, or essentially burn, the small areas of tissue causing the problem. Wharton notes that these procedures have high success rates in eliminating the arrhythmias with low rates of recurrence.

Recovery times are also fairly short. Often the small wounds in the groin where the catheters are inserted are the only areas that take time to heal. Patients, and even high-level athletes, can expect to return to normal activities, and even sports, within days. Fish, in fact, hopes to play in the AEGON Championships at the Queen’s Club starting June 11.

To tennis players at all levels and any other athletes who experience similar feelings of a racing or pounding heart, Dr. Wharton stresses that they should not dismiss them as anxiety. When in doubt, athletes should consult with a physician to check the heart as well.

Often the fear of not knowing when these terrifying episodes will occur is the worst part of these conditions. “It makes people crazy. They don’t know when it will happen,” he explains. The peace of mind provided by these cardiac ablations can be profound.

Tennis fans can rest assured that the American star will return to the courts soon and hopefully back to the top of the tennis rankings. Mardy Fish, on the other hand, is likely relieved to finally get some rest at all.

Dr. David Geier is an orthopaedic surgeon and Director of MUSC Sports Medicine. For more information about tennis injuries and other sports medicine topics, go to Dr. Geier’s blog at drdavidgeier.com.