European Heart Journal Advance Access originally published online on December 7, 2007
European Heart Journal 2008 29(1):71-78; doi:10.1093/eurheartj/ehm555
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Sinus node disease and arrhythmias in the long-term follow-up of former professional cyclists
1 Cardiovascular Center Zurich, Klinik Im Park, Seestr. 220, 8027 Zurich, Switzerland
2 Division of Cardiology, University Children’s Hospital, Zurich, Switzerland
3 Department of Biostatistics University of Zurich, Zurich, Switzerland
4 Outpatient Clinic Othmarsingen, Zurich, Switzerland
5 HerzZentrum Hirslanden, Zurich, Switzerland
6 Division of Cardiology, University Hospital Zurich, Zurich, Switzerland
7 Institute of Sports Science Magglingen, Zurich, Switzerland
Received 6 February 2007; revised 16 October 2007; accepted 5 November 2007; online publish-ahead-of-print 7 December 2007.
* Corresponding author. Tel: +41 44 209 20 20, Fax: +41 44 209 20 29. Email: ch.attenhofer{at}attglobal.net
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.
Key Words: Cyclists • Sinus node disease • Arrhythmias • Endurance training • Atrial fibrillation • Atrial flutter