LONDON — Mardy Fish was high above Wimbledon, perched on a stool in the players’ restaurant with a panorama of green courts and tennis whites stretched out behind him like a landscape painting.  It was a peaceful afternoon, but Fish was here to talk about troubled nights, and at one stage Saturday he lifted his shirt to show the circular red marks on his torso left by suction cups used to secure a heart-rate monitor to his chest every night for weeks.  “I have one here, one here and one here,” Fish said, touching the marks. “It was really uncomfortable to sleep in, but it made me feel comfortable. I still have it with me.”  Fish, a sensitive 30-year-old American, took his game to a higher plane over the past two seasons: he changed his diet, whipped himself into career-best shape and was ranked in the top 10 for the first time ever in 2011. Long talented, he was now fully committed, and he reveled in qualifying last year for the A.T.P. World Tour Finals, held in London in November and reserved for the top eight in the rankings.  Back in London seven months later, Fish is in a much more vulnerable place. He struggled to find the same form in the early season and had a heart procedure known as cardiac catheter ablation in Los Angeles on May 23. It was done in an attempt to resolve a form of arrhythmia that Fish’s physical trainer, Christian LoCascio, said was called supraventricular tachycardia.  Though Fish is still ranked 12th, and seeded 10th at Wimbledon, he has played only one match since March, when he woke up in the middle of the night in his hotel room after losing to Juan Mónaco in the quarterfinals at the Masters 1000 event in Miami.  Fish said his heart was racing, and that he could find no way to slow it down, not as he lay in bed and not as he paced his room with increasing panic.  “I honestly felt in Miami like I was going to die,” Fish said. “I had just read that story about that soccer player.”  He was referring to Fabrice Muamba, the 23-year-old Bolton player who collapsed on the field after a cardiac arrest during an F.A. Cup match on March 17. Muamba’s heart stopped beating for more than an hour, but he survived.  Fish said he was also thinking about Nathan Healey, a former tennis player from Australia who required emergency heart surgery in March, at age 32.  He was thinking of how to slow his pulse rate. “It’s pumping so hard, like out of my chest, beating so hard,” he said. “If I were to just drop everything and just do a full sprint outside the grounds here at Wimbledon, that’s how fast it was going.”  After several failed attempts, he said, he reached LoCascio. Fish was taken to a hospital by ambulance at about 4 a.m. for treatment.  The episode was the latest and most frightening in a series for Fish. He said the first occurred in February during the first round of Davis Cup play in Switzerland, when he woke up with a racing heartbeat. He pounded on LoCascio’s hotel room door across the hall in the middle of the night.  His heart rate quickly returned to normal, and he went out the next day and defeated Stanislas Wawrinka in a five-set marathon as the United States went on to upset the Swiss.  Fish said the start of the year had been difficult psychologically for him as he struggled to reproduce his 2011 form.  “No one is immune to the pressure of expectation, not one single human being is immune, look at Albert Pujols,” he said, referring to the Los Angeles Angels baseball player. “You see what’s written or you hear what they are saying on TV and the commentators are putting you down and you feel uncomfortable about that because you’ve never gone through anything like that and this is a different position.”  He said he had other nighttime concerns with his heart in the weeks that followed but that Miami was “the tipping point,” convincing him he needed medical attention. He consulted cardiologists in Vero Beach, Florida. Fish said doctors told him his condition was not life-threatening.
The American tennis player has arrived in England to play at Wimbledon after numerous concerns about his health.