Atrioventricular block, including Mobitz type II-like pattern, during ambulatory ECG recording in young athletes aged...

Twenty young male athletes, aged 14 to 16 years, and 20 nonathletic male controls of the same ages were studied with regard to atrioventricular block using ambulatory ECG recording. Among the athletic youngsters, the mean hourly heart rates were significantly (p less than 0.01) lower during most of the night hours and during school hours when activities in both groups were uniform. First degree block was found in the athletes in 3 cases, second degree Wenckebach-type block in 3 cases and second degree block with Mobitz type II-like pattern in 2 cases. Among the nonathletes, first degree block was found in one case and second degree Wenckebach-type block in another. The results indicate that after approximately 3 years of physical training, on average 5 times a week, various forms of atrioventricular block, apparently vagally mediated, are observable in young athletes more often than in nonathlete controls.