NEW YORK -- Elite runner Ryan Shay died of an irregular heartbeat due to an enlarged heart after collapsing during the U.S. men's marathon Olympic trials, the New York City medical examiner said.
Shay's heart also had old scarring, but its cause could not be determined, according to Ellen Borakove, a spokeswoman for the medical examiner.
The 28-year-old Shay collapsed in Central Park on Nov. 3, about 5½ miles into the race, and was pronounced dead at a hospital.
His father, Joe Shay, said previously that Ryan was diagnosed with an enlarged heart at age 14. But doctors had repeatedly cleared him for competition, because having a larger than normal heart is not unusual among elite athletes. Training hard in aerobic sports, such as cycling, running or swimming, tends to result in a bigger heart that pumps more blood throughout the body.
Dr. Douglas Zipes, a spokesman for the American College of Cardiology, who studies sudden deaths in athletes, said previously it can be difficult to differentiate a normal athlete's heart from potentially deadly hypertrophic cardiomyopathy.
Cardiac echo tests and electrocardiograms can help evaluate whether the heart is healthy or not, said Zipes, a distinguished professor at the Indiana University School of Medicine. Genetic testing can also determine whether a person is at risk for certain problems.
Zipes will sometimes have athletes stop training for a month in an attempt to learn why their hearts are enlarged. Healthy athletes' hearts will shrink during that time. The size won't decrease if they suffer from hypertrophic cardiomyopathy, a disease in which a portion of the heart muscle is thickened without any obvious cause.
After his son's death, Joe Shay said doctors could not adequately test Ryan using a treadmill when he was a teenager because his heart rate was so low. Zipes said that's not uncommon among elite athletes.
Shay was born May 4, 1979, in Ann Arbor and was the fifth of eight children in a running family. His parents are the cross country and track coaches at Central Lake High School in Michigan.
He was an All-American at Notre Dame, where he earned a national individual track title in the NCAA 10,000 meters. Shay went on to become a five-time national road racing champion.
At Shay's funeral, his professional coach, Joe Vigil, said he had been surprised by Shay's decision to be a marathon runner from the start instead of focusing on shorter distances and working up to marathons, as racers typically do.
"Not Ryan. He knew what he wanted -- immediately," Vigil said. "He taught us a lesson in how relentless he was in pursuit of his goals."
About 125 athletes under 35 involved in organized sports die of sudden death in the United States each year, Dr. Barry J. Maron of the Minneapolis Heart Institute Foundation said previously. The institute tracks such deaths in a national registry.
An analysis of 387 cases from the registry showed the vast majority were cardiac-related. About a quarter involved hypertrophic cardiomyopathy. About 20 percent were from a blow to the chest, such as being hit by a bat or ball.
Maron said many of the cardiac diseases that can lead to sudden death can be spotted through screening.
Maron helped write heart association guidelines that help doctors screen athletes for sudden death. The process includes questions that focus on spotting potential heart problems through a personal and family medical history and a physical exam.
Shay had medical tests last spring in Flagstaff, Ariz., where he trained, and was cleared for running, according to his father. Joe Shay said his son hadn't complained of any problems.