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Climber Defies the Odds to Summit Everest After Heart Condition Diagnosis

9 minute read

Peter Horsman, a native of the Netherlands, fell in love with mountain climbing as a teenager. He went on to conquer some of the world's most challenging peaks—from Ecuador's Chimborazo and Alaska's Denali to Russia's Elbrus and Argentina's Aconcagua. His long-term dream was to summit the highest mountain on each of the seven continents.

That dream nearly came to an end when he was diagnosed with a heart disorder. His local cardiologist said continuing to climb would be too stressful for his heart.

"He was very resolute, saying 'no sports at all—the risk is too high,'" Peter said. "I was devastated."

Refusing to give up, Peter sought a second opinion at the Cardiovascular Performance Program (CPP) at Mass General Brigham Heart and Vascular. With the CPP team's guidance, he safely returned to climbing and eventually summitted the tallest mountain in the world: Mount Everest.

A threat to his vigorous lifestyle

Peter, who lives in Seattle, learned he had hypertrophic cardiomyopathy (HCM) at age 46. HCM is a genetic heart condition that often goes unnoticed until it's found during testing. He felt perfectly fine at the time and only underwent testing because both his sister and father had been diagnosed recently.

HCM causes the muscle of the heart's left ventricle to thicken. In some cases, this makes it harder for the heart to pump blood to the rest of the body. In other cases, it can lead to sudden cardiac death.

For Peter, who enjoys hiking, running, and swimming in addition to climbing, the diagnosis came as a shock. He wasn't ready to abandon the lifestyle he loved.

While researching Peter's case, his cardiologist came across the CPP. The program offers specialized cardiac care for athletes and other highly active people, including screenings, fitness assessments, and surgical and nonsurgical treatments for heart disease.

After receiving a referral from his cardiologist, Peter flew to Boston to see if the CPP could help him.

Serving athletic patients with heart disease

Peter during icefall training.

Founded in 2009, the CPP is the first program of its kind. Its team, including four cardiologists, two nurse practitioners, and an exercise physiologist, focuses on the distinctive needs of athletic patients with heart disease. One of the program's key strengths is developing personalized treatment plans that consider the cardiovascular demands of exercise and help identify when it's safe to return to athletic activity.

According to CPP director Sawalla Guseh, II, MDcardiology has traditionally been "a risk-averse field."

"We might be able to treat your disease, but then we tell you not to exercise. In many cases, that's doing the patient a disservice," he said.

Through the program's deep focus on exercise science and heart disease, the CPP helps patients return to sports and physical activity in a way that protects their health. "That has substantial physical and mental benefits," Dr. Guseh noted.

During his first appointment at Mass General Brigham, Peter underwent an echocardiogram and performance testing in the CPP's state-of-the-art Cardiopulmonary Exercise Laboratory. He then met with Aaron Baggish, MD, the program director at the time, and nurse practitioner Katie Morganti Stewart, CNP, to review the results.

The news was positive: Although Peter would need to keep an eye on his heart rate while active, his athletic career wasn't over. As Dr. Baggish explained, HCM cannot be cured—but it is possible to manage the risks safely.

Peter left the visit reassured and energized. "I remember walking over to Boston Harbor after that and looking out over the water," he said. "I decided then and there that I would try to climb Mount Everest."

Mapping out a plan

Peter poses with a picture from his summit with his providers, Dr. Guseh and Katie. Dr. Baggish is pictured in the bottom left corner.

Peter began saving up his money and intensifying his training in preparation for Mount Everest. At his annual visit to the CPP four years later, he revealed his plan to Dr. Guseh, who had recently taken over Peter's care from Dr. Baggish.

Dr. Guseh carefully assessed the safety of an Everest climb, including:

  • Reviewing Peter's latest performance test results, which showed excellent heart function
  • Having multiple discussions with Peter about his goals and the risks involved
  • Designing a training plan to help Peter adapt to the physical demands of high altitudes

At each follow-up visit, testing showed Peter's extensive training had further improved his heart health. Dr. Guseh then gave him the go-ahead to climb Mount Everest.

"Most people with HCM historically have been shut down," Dr. Guseh said. "But our team doesn't believe in making blanket decisions about patients with a particular form of heart disease. Long ago, we invested in technology that allows us to understand each person's unique risk, so we can make informed, personalized recommendations.”

Peter said that collaborative approach made all the difference.

Both Dr. Guseh and Dr. Baggish are very good at partnering with you. They've never told me what I can or can't do. It's still my decision; I'm still accountable for what I'm going to do. I appreciate that kind of partnership.

Peter Horsman

On top of the world

A dramatic shot of a ridge of Mt. Everest, seen from above. Mountaineers are making their way along a trail, dwarfed by the landscape.

Climbing Mount Everest usually takes about two months. Peter's team spent the first week and a half hiking to Everest Base Camp. There, his heart monitor detected several incidences of abnormal heart rhythms. Dr. Guseh and Katie had mentioned these rhythms would likely occur, so they came as no surprise. After consulting with volunteer doctors on site, Peter decided to proceed with the climb. Fortunately, he had no further irregularities in his heart rhythm.

After several weeks of acclimatization hikes to help his body adjust to the higher altitudes, it was time for the final summit push. Peter hiked from Camp 4 (the final high camp) to the summit in less than eight hours—an impressive pace for anyone. He and three fellow climbers spent 90 minutes on the summit, over 29,000 feet above sea level.

"We had perfect conditions—such blue skies," he said. "I could see the curvature of the earth. It was amazing. It's hard to put into words how awesome it was."

Peter felt strong throughout the summit push and the ensuing descent to Camp 4. Since the conditions were still good, he chose to go forward with his plan to climb Mount Lhotse, which abuts Mount Everest and is the world's fourth-tallest mountain.

He went on to become the first Dutch person to summit both Mount Everest and Mount Lhotse in less than 24 hours. The 18-hour descent to Camp 2 was extremely challenging, especially after he ran out of supplemental oxygen. As exhaustion set in, he pulled out one of his daughter's motivational cards from his backpack. The message gave him the strength to keep moving, knowing that resting in such extreme conditions could be fatal.

Two days later, Peter was on a plane home to Seattle.

No signs of slowing down

Peter Horsman smiling in climbing gear, rappelling up a cliff.
Peter climbing in the “Death Zone” of Mount Everest.

Almost two years after his Everest adventure, Peter remains an active climber. He frequently summits the nearby Mount Rainier, sometimes with new graduates of a climbing class that he teaches. And he's still working toward his goal of summiting each continent's tallest mountain. Next on his list: Mount Vinson in Antarctica.

"I'm grateful to my cardiologist in Seattle for referring me to Mass General Brigham," Peter said. "And I'm grateful to Dr. Baggish, Dr. Guseh, and Katie for building a program that offers individualized treatment so that people like me can keep living their dreams."

"Peter's case is emblematic of what we believe at the CPP: Heart disease shouldn't mean the end of the life you love," Dr. Guseh concluded. "With the right care, people can continue to live fully and fearlessly."


Learn about Mass General Brigham Heart and Vascular services