Electrocardiographic findings in male veteran endurance athletes.

Abstract

SUMMARY Twenty male veteran endurance runners and 20 controls underwent resting, exercise, and ambulatory electrocardiography. Four athletes and three controls satisfied voltage criteria for left ventricular hypertrophy. The PR interval was longer in the athletes and they had longer mean (SD) treadmill exercise times (19 (4) v 16 (2) min) than the controls. Four athletes but no controls had > 2 mm downsloping ST segment depression during exercise. During 48 hour ambulatory electrocardiography the athletes had a consistently lower heart rate but maintained a circadian variation. Profound bradycardia (< 35 beats/min) occurred in eight athletes but only one control. Eight athletes and two controls had asystolic pauses ranging from 1-8 to 15 seconds. Six athletes had first degree heart block, four had Mobitz II second degree block, and three had complete heart block. Most conduction abnormalities occurred at night and resolved during exercise. Ventricular ectopic activity was not significantly different between the groups.Thus heart block patterns and profound bradycardia are more frequent in older athletes than their youthful counterparts.

Ambulatory Electrocardiographic Findings in Top Athletes, Athletic Students and Control Subjects

“…The prevalence was low and it was not higher in top athletes than athletic stu dents. Increased prevalence of AV block II in athletes compared to controls has been found by other authors [10,19,20,22,25,26]. Most blocks occurred during the night, and Viitasalo et al [10] demonstrated that blocks had the highest prevalence during sleep-related rapid changes in heart rate probably induced by changes in the autonomic nervous tone.…”

“…(tables 1, 3) The number of VPB was low in all groups and no consistent differences could be found. The prevalence of VPBs has been reported in matched trained and untrained groups [12,19,21,22] of varying ages and range between 17 and 90%, but the differences are not con sistent and not statistically significant. While Palatini and Sperti [12] suggested an in creased prevalence of complex ventricular ar rhythmias in athletes based on a prolongation of the QT time, Freggiaro et al [21] found a low prevalence which is supported by the results of the present study.…”

“…Most blocks occurred during the night, and Viitasalo et al [10] demonstrated that blocks had the highest prevalence during sleep-related rapid changes in heart rate probably induced by changes in the autonomic nervous tone. Atrioventricular block grade III is rare, but is possibly more common in veteran athletes [22]. Regression of such AV blocks on de training has been reported [27], suggesting increased vagal tone as a cause.…”

“…In our study the vast majority of blocks were Mobitz type I and all episodes of Mobitz type II block had narrow QRS complexes pointing to a proxi mal location. Long ventricular pauses induc ing syncopal attacks in athletes have been reported [7,[29][30][31], which in some cases led to pacemaker implantation [7,32], Ventricu lar pauses of up to 15 s have been recorded [22] using ambulatory monitoring. Most stud ies report a maximal pause of 3-5 s in athletes (the majority finding 3-3.5 s) and 2 s in sed entary controls, which is in agreement with our findings.…”

12-lead ECG in the athlete: physiological versus pathological abnormalities

“…Resting sinus bradycardia, as defined by a heart rate <60 beats/min, is almost universal in athletes, depending on the type of sport and the level of training/competition 18 19 20. Escape junctional beats or rhythm may be recorded in athletes with more severe bradycardia and result in functional AV dissociation.…”