Restoring the Heart of an IRONMAN®

The IRONMAN® Triathlon is one of the most demanding endurance competitions in the world. Athletes train year-round to push themselves past their mental and physical limits, burying self-doubt and ignoring overwhelming exhaustion.

As a lifelong marathoner and triathlete, Kevin McCarthy knew what was required to compete in such a grueling race. He accepted the challenge in his 40s, unaware a hereditary heart condition was slowly progressing, masked by the training and difficult recovery he assumed were part of the process.

“I competed in my first IRONMAN® in 2021,” McCarthy said. “I did pretty well, but I don’t consider myself to be an athlete. I just have the ability to suffer through training and competition because I want to finish the race. Looking back, I think my heart was already affecting my performance.”

Peak Performance to Rock Bottom

By 2023, McCarthy was living in Fernandina Beach, Florida, and registered for the Panama City IRONMAN® qualifier. As anticipated, training was difficult, but he pushed forward, relying on his ability to endure and reach the starting line. The race consisted of a 2.4-mile ocean swim and a 112-mile bike ride and ended with a demanding 26.2-mile run. McCarthy struggled the most during the running portion of the race, barely able to maintain the minimal pace required to reach the finish line in the allotted 17 hours.

In the months following the Panama City event, McCarthy’s recovery was slow. He didn’t bounce back as expected. Simple, everyday tasks seemed challenging and eventually, light activity like moving wooden pallets and even walking his dog would lead to sharp chest pain.

Also concerning was the fact that his discomfort was consistently present during light physical exertion but would subside as quickly as it escalated. McCarthy was experienced in competing through a high level of discomfort, so for him, this lower-level pain was his signal to seek help.

After an initial visit to a local urgent care facility, McCarthy was directed to see a cardiologist for an advanced evaluation. He underwent a cardiac catheterization, a test that measures the blood pressure within the heart and how much oxygen is in the blood. Catheterizations are used to diagnose coronary artery blockages in the case of coronary artery disease and heart attacks. At his follow-up visit, McCarthy was told his declining stamina and frequent chest pain was due to a chronic total occlusion, or CTO, in his right coronary artery. Unlike an abrupt blockage that can cause a sudden heart attack, a CTO develops more slowly over time. Beginning as a buildup of plaque within the artery, a CTO will eventually reduce the blood flow to the heart.

Genetics and Disappointing Advice

Although his diagnosis was unsettling, McCarthy was not completely surprised by the results, as he had lost his father to heart disease many years earlier. Despite his dedication to a healthy, active lifestyle, he was unable to outrun his genetics without medical intervention. What surprised McCarthy were the treatment options presented to him by the first heart specialist he was treated by.

“My diagnosis made sense, based on my family history,” McCarthy said. “What didn’t make sense was how they wanted to deal with it. They said I had two options — I could undergo bypass surgery, which everybody knows is a big deal, or I could manage the problem with medication and greatly reduce my activity to walking and very light exercise. I was barely 50. I run triathlons. Those are the type of options you give to a person in the later years of their life.”

Never Give Up — Second Opinions Matter

Not satisfied with his treatment options, McCarthy looked for a second opinion and met with another cardiologist, who, after running more tests, concluded that his CTO was more complex than originally diagnosed. The specialist explained that although his condition was complex, the original therapeutic plans presented to McCarthy were not his only course of action and referred him to Calvin Choi, MD, at UF Health Heart & Vascular –Jacksonville.

Choi is an interventional cardiologist and director of the Cardiac Catheterization Laboratory at UF Health Jacksonville. He is an expert in the percutaneous management of complex coronary artery disease, as well as structural and valvular heart disease. Additionally, Choi has extensive experience in CTO and transcatheter heart valve interventions.

In addition to his extensive procedural experience with CTO, Choi was also a former IRONMAN® competitor. He understood that McCarthy’s original treatment options were not something an athlete at his level was going to take lightly but explained there was more that could be done with a far better outcome.

“We talked through all the risks and benefits,” Choi said. “I explained it was a difficult procedure, but it was a specialized, minimally invasive treatment to reopen the blocked artery and place a stent. These CTO interventions are technically demanding and not widely performed, but they can be very effective in the right patient.”

Within days of his 2025 consultation, McCarthy was admitted to UF Health Jacksonville, where Choi and the interventional cardiology team made a small incision in his groin and guided a stent to the site of the blocked artery. With the stent in place and blood flow to his heart properly restored, McCarthy’s surgery was a complete success, and he was home recuperating within a day.

Restored Flow, Immediate Impact

“I followed Dr. Choi’s guidelines,” McCarthy said. “I took it easy at first but immediately noticed a difference in how I felt. At my follow-up appointment, I mentioned to Dr. Choi that I’d like to start running again as soon as possible. When he told me I was clear for training I signed up for a 5K. I was shocked to see my 12-minute miles were down to around 10 minutes. I hadn’t felt that good since I was 17 years old.”

One year after undergoing CTO surgery, McCarthy has reduced his four medications to just aspirin and statin and has transitioned to an almost fully vegan diet. He continues to exercise at a high level but has adapted a routine focused on efficient output and strategic recovery.

With the upcoming 2026 IRONMAN® Jacksonville event on May 16, McCarthy is once again focused on completing one of the most grueling endurance sports on the planet. He still leans into his “ability to suffer” to reach the finish line, but McCarthy now does so with a newfound confidence. For many years he pushed his body to the breaking point, unaware that no matter how hard he trained, his genetics were always slowing him down.

“I have a new lease on life,” McCarthy said. “For years, I thought I was giving everything I had, but I didn’t realize my heart was holding me back in a way that was out of my control. Now that my arteries are fully open, I feel better than ever and I’m not focused on just finishing the race. I want to really compete. If all goes well, I could finish in just 14 to 15 hours.”

I’m really happy for him,” Choi said. “The IRONMAN® is extremely difficult. To go from peak performance, to being unable to exercise and then back again is powerful. It highlights the importance of pushing forward, never giving up and getting a second opinion, when necessary, at a tertiary care center like UF Health. In his case, it made all the difference.”

Visit UFHealthJax.org/heart to learn more about heart disease and treatment options at UF Health Jacksonville.