title: Ambulatory electrocardiographic monitoring in 100 healthy teenage boys.
abstract: Ambulatory monitoring of the electrocardiogram in 100 healthy 14 to 16 year old boys showed heart rates ranging from 45 to 200 beats/minute during the day and from 23 to 95 beats/minute during sleep. Sinus arrhythmia was present in all cases and was the only variation noted in 17%. Sudden variations in the PP interval occurred in 41%, but a precise diagnosis of the mechanism was usually impossible; 15% had changes compatible with sinus arrest or temporary complete sinoatrial block, and one boy had a pattern compatible with type II second degree sinoatrial block. Escape rhythms were noted in 26%, first degree atrioventricular block in 12%, and second degree atrioventricular block (Mobitz type I) in 11%. Mobitz type II second degree atrioventricular block was seen on one occasion in one boy. Ventricular extrasystoles seen in 41% were of uniform morphology in 75% and multiform in 25%. Short episodes of ventricular tachycardia were recorded in 3%.
mesh_terms: D000293:Adolescent; D001146:Arrhythmia, Sinus / Q000503:physiopathology; D005117:Cardiac Complexes, Premature / Q000503:physiopathology; D002940:Circadian Rhythm; D004562:Electrocardiography; D006321:Heart / Q000502:physiology* / Q000503:physiopathology; D006327:Heart Block / Q000503:physiopathology; D006339:Heart Rate; D006801:Humans; D008297:Male; D008991:Monitoring, Physiologic; D012890:Sleep