Carlos Perez was wrapping up a day of work at his car repair shop in June 2025 when his evening took a frightening turn. The 72-year-old mechanic sat down with a glass of water, intending to rest a few minutes before driving home, when his heart suddenly began to pound and his chest started to ache. When he tried to stand, he said, "the world narrowed."
"I said, 'Oh, no way,'" Perez recalled. "It was coming in waves." He phoned his daughter-in-law, a doctor, who told him to get to an emergency room. His wife drove him to the hospital, where physicians determined he was in atrial fibrillation, an irregular heartbeat that, if untreated, can lead to stroke or heart failure.
His rhythm settled after roughly 90 minutes, but the cause remained a mystery. A round of tests turned up nothing obvious until an advanced scan examined both sides of his heart. "One doctor came in, then two doctors, and then a whole bunch of doctors went into the room," Perez said. "And they said, 'No, no, don't worry. It's just that we've all read about it, but we've never seen a patient with this.'"
Perez had cor triatriatum, a congenital defect in which a membrane divides one of the heart's upper chambers in two, giving the heart five chambers instead of four. Left untreated, it can trigger pulmonary hypertension and eventually dangerous rhythm problems. About 0.8% of babies are born with some form of congenital heart disease, said Dr. Wayne Franklin of Children's National Hospital, and cor triatriatum makes up just 0.1% of those cases, roughly 1 in 10,000.
The condition is almost always caught before birth or in infancy and repaired early; when it is not, it usually surfaces in a person's 30s or 40s, Franklin said. Perez had gone more than seven decades without major problems. "Most patients with this condition don't really survive this long," said Dr. Tom Nguyen, chief medical executive of the Baptist Health Miami Cardiac & Vascular Institute. "Carlos was very lucky to have lived this long." A small opening in the membrane had let blood flow close to normally, Nguyen explained, but it narrowed with age until his heart began showing signs of atrial fibrillation.
Medication was tried first, but a second episode in September sent Perez back to the ER, where doctors shocked his heart back into rhythm. Surgery was now unavoidable. Nguyen and cardiac surgeon Dr. Makoto Hashimoto, both on faculty at the Florida International University Herbert Wertheim College of Medicine, faced an adult heart unlike any they had operated on, so they consulted Dr. David Kalfa, chief of cardiovascular surgery and co-director at Nicklaus Children's Hospital's Heart Institute, who had treated the defect in children.
Rather than the open-heart operation standard in infants, the team attempted a minimally invasive robotic procedure. Perez underwent surgery on Jan. 7, 2026, and the membrane was removed robotically, with magnification of up to 10 times helping surgeons distinguish what to cut and what to leave, Nguyen said. Perez was left with only a few small incisions, called the experience "like science fiction," and went home in under a week. He has since returned to his active lifestyle.
Perez will need lifelong monitoring and medication for possible atrial fibrillation, but Kalfa said his cor triatriatum can be considered cured. "It's kind of a Cinderella story, of him being in the right place at the right time," Nguyen said.
The partnership has continued. In August, the three doctors performed a robotic cardiac surgery at Nicklaus Children's Hospital that Kalfa said was the first of its kind in Florida, treating a congenital defect in a teenage boy who went home a day later. The hospital has also launched a pediatric robotic cardiac program, only the second in the United States. "This pediatric knowledge helped an adult patient, then goes back to the pediatric population," Kalfa said. "It's kind of beautiful."
