MASON, Ohio -- Mardy Fish knows what it's like to be at the top of the world one day and then hit rock bottom overnight.
It was only a few months into 2012 when Fish was enjoying the best stretch of his career. He was ranked in the top 10 in the world and was the top-ranked American man in the game.
But that's when a frightening health issue emerged and turned his world upside down. Not only did Fish have to deal with a heart problem unusual for a guy in his early 30s, but he was also mentally unprepared to handle the situation.
In the middle of the night after he lost to Juan Monaco in the Sony Open quarterfinals in March 2012, Fish's heart started to race uncontrollably, which sent him to the emergency room. He would undergo a cardiac catheter ablation procedure weeks later to reset his heartbeat.
While Fish played well during the summer of 2012, the worry about how his heart would handle the physical exertion caused him constant anxiety. It was during the US Open that Fish finally concluded he was ill-equipped to get beyond his personal demons on his own and would need to seek professional help.
"There was a lot of that [fear], for sure," Fish said. "[It was] probably 3:30 a.m. after I beat Gilles Simon in [the third round of] the US Open last year. That's when I knew I had some issues. I've come a very long way, but it's been a very slow process."
Fish had every intention to play his fourth-round match against Roger Federer, even arriving at Flushing Meadows to prepare, but once there, Fish couldn't bring himself to step out on the court -- and wouldn't again for months.
"There's a lot of things that I'm working on as well, to manage -- sort of manage the stresses of matches and everyday life and stuff, so sometimes I'm speaking with psychiatrists and things like that on a week-to-week basis," Fish said.
Not surprisingly, Fish has been reluctant to talk about his health -- saying he's still not 100 percent -- and the problems he's incurred in accepting and living with this unexpected turn of events.
On Monday, after his 7-5, 6-2 first-round loss to Philipp Kohlschreiber at the Western & Southern Open, Fish confirmed the rumor that he temporarily suffered from agoraphobia following last year's US Open.
"I probably spent three months straight inside my house," he said. "I think I went in the backyard maybe a couple of times."
While Fish, ranked No. 129, knows that none of what he's gone through will ever disappear from his memory bank, he's learning how to move on and live life. What he doesn't know is how long his life will continue to include playing professional tennis.
"Matches like today, and days like today, really make you sort of question how far you've got to go, if there's still that sort of fire and drive that you need," Fish said. "This is not an easy game in that regard at all. When you get to be out here for that long, for this long, it becomes challenging, for sure."
For now, Fish is playing doubles in Ohio; he and partner Jurgen Melzer defeated Jarkko Nieminen and Gilles Simon in the first round Monday. Fish reached the Washington, D.C., doubles final with Radek Stepanek two weeks ago. And he plans to play at Winston-Salem next week ahead of the US Open.
"I think there's going to be some sort of assessment period, maybe after the US Open, where I'll kind of see -- feel -- how far away I am from where I want to be," he said. "I mean, with all these problems that I had health-wise, I left the game in the top 10 in the world, and that's pretty hard to deal with. It was very, very hard to get there and to stay there for a little while.
"So it's been very hard and very challenging to know that I had really no control over it."
What Fish considers the silver lining of his ordeal is that, no matter what's happened or will happen, his wife, Stacy, has remembered her wedding vows to stick closely by his side "in good times and bad times."
"Stacy's been a rock," said Fish of his wife of nearly five years. "She's been an angel, really. I'm not sure, without her there's no telling -- without her help after the US Open, there's no telling where I'd be. This is a scary time for sure."