Runners get to heart of the matterLocal | Stella Wong 1 Feb 2019
Marathon runners should undergo medical checks as a study found that 0.97 percent of the Hong Kong population has a rare congenital heart abnormality that may cause sudden cardiac death under strenuous activity.
Union Hospital conducted a study of 10,098 patients from September 2013 to March 2018 and discovered that 98 patients have anomalous coronary artery, meaning that their coronary arteries have abnormalities or malformations.
Steven Li Siu-lung, head of internal medicine and director of the heart center at the Union Hospital, said they can experience sudden death under strenuous activity.
"In our study, two experienced complications in a stress test, with one resuscitated, and the other discovered to have ischemia [reduced blood flow to a specific organ]," he said.
One of the patients, 45-year-old Ng Kwok-fung, is a marathon runner with over 10 years of experience under his belt.
He regularly undergoes health checks and his heart was reportedly healthy.
However, Ng fainted in a marathon held in Japan's Ehime Prefecture in February, but his case was treated as heat exhaustion.
Two weeks later, he finished a half marathon in Hong Kong with no problems.
But when Ng participated in another marathon in Japan's Shizuoka Prefecture in March, he suddenly collapsed and was resuscitated immediately after.
Li said Ng's right coronary artery arose to the left, which led to the compression of the ascending aorta and pulmonary artery.
When the two major arteries continue to contract and relax in strenuous exercise, it compresses the coronary artery and reduces blood supply to the heart - resulting in cardiac ischemia, Li said. Prolonged cardiac ischemia can cause sudden death.
Ng underwent surgery at Queen Mary Hospital to re-position and unroof his right coronary artery in April. He returned to competing in marathons and took part in the RunOurCity event last month.
He is now gearing up to compete in the full marathon at the Standard Chartered Hong Kong Marathon on February 17.
Li said people who have this condition may not experience symptoms before sudden death, and these issues can only be detected via multidetector computed tomography, a diagnostic imaging test that is not included in basic health examinations.
He said citizens should not be overly concerned and advised marathon runners to undergo a check with a treadmill before a race. He also added that runners should be wary of symptoms when training.