Aims Significant brady- and tachyarrhythmias may occur in active endurance athletes. It is controversial whether these arrhythmias do persist after cessation of competitive endurance training.
Methods and results Among all 134 former Swiss professional cyclists [hereafter, former athletes (FAs)] participating at least once in the professional bicycle race Tour de Suisse in 1955–1975, 62 (46%) were recruited for the study. The control group consisted of 62 male golfers matched for age, weight, hypertension, and cardiac medication. All participants were screened with history, clinical and echocardiographic examination, ECG, and 24 h ECG. The time for the last bicycle race of FAs was 38 ± 6 years. The mean age at examination was 66 ± 6 years in controls and 66 ± 7 years in FAs (P = 0.47). The percentage of study participants with >4 h current cardiovascular training per week was identical. QRS duration (102 ± 20 vs. 95 ± 13 ms, P = 0.03) and corrected QTc interval (416 ± 27 vs. 404 ± 18, P = 0.004) were longer in FAs. There was no significant difference in the number of isolated atrial or ventricular premature complexes, or supraventricular tachycardias in the 24 h ECG; however, ventricular tachycardias tended to occur more often in FAs than in controls (15 vs. 3%, P = 0.05). The average heart rate was lower in FAs (66 ± 9 vs. 70 ± 8 b.p.m.) (P = 0.004). Paroxysmal or persistent atrial fibrillation or flutter was reported more often in FAs (P = 0.028). Sinus node disease (SND), defined as bradycardia of <40 b.p.m. (10 vs. 2%), atrial flutter (6 vs. 0%), pacemaker for bradyarrhythmias (3 vs. 0%), and/or maximal RR interval of >2.5 s (6 vs. 0%), was more common in FA (16%) than in controls (2%, P = 0.006). Observed survival of all FAs was not different from the expected.
Conclusions Among FAs, SND occurred significantly more often compared with age-matched controls, and there is trend towards more frequent ventricular tachycardias. Further studies have to evaluate prevention of arrhythmias with extreme endurance training, the necessity of regular follow-up of heart rhythm, and management of arrhythmias in former competitive endurance athletes.