LEUVEN, Belgium -- Ventricular arrhythmias that occur in endurance athletes such as competitive bicyclists may originate on the right side of the heart, and could be a consequence of no-holds barred training and performance.
LEUVEN, Belgium, Jan. 26 -- The body-punishing training of endurance athletes may be putting their hearts to the test, according to investigators here.
Arrhythmias that occur in endurance athletes such as competitive bicyclists may originate in the right ventricle, and may be a consequence of intensive training and performance, suggested Hein Heidbchel, M.D., Ph.D., of the the University of Leuven here, and colleagues.
The findings provide further evidence that endurance sports may cause structural remodeling of the heart that could lead to arrhythmias, they reported in the Jan. 22 issue of the European Heart Journal.
"Our study clearly demonstrates right-ventricular functional abnormalities in high-level endurance athletes with ventricular arrhythmias," Dr. Heidbchel said. "The observed right-ventricular dysfunction is more subtle than in familial or overt arrhythmogenic right-ventricular cardiomyopathy. Arrhythmogenic right-ventricular cardiomyopathy was present in only a minority of the athletes, based on conventional, internationally accepted criteria."
The investigators enrolled 22 Dutch and Belgian male endurance athletes -- primarily bicyclists and kayakers -- who had been referred to their center for evaluation of ventricular arrhythmias. They were compared with 15 matched endurance athletes without arrhythmias, and 10 non-athletes without arrhythmias.
The men were determined to be endurance athletes if they took part in intense endurance sports lasting for at least two hours per session three times a week for at least five years.
The author used four methods for quantitative right ventricular angiographic analysis (area length, Boak, pyramid monoplane, and pyramid biplane) to calculate right ventricular end-diastolic volume and end-systolic volume (corrected for body surface area) and ejection fraction. They also looked at right ventricular outflow tract shortening fraction in the participants.
They found that although only 27% (6 of 22) of athletes with ventricular arrhythmias fulfilled the diagnostic criteria for arrhythmogenic right ventricular cardiomyopathy, "involvement was manifest or probable in 82%, based on a combination of electrophysiologic, electrocardiographic, and morphologic criteria."
In athletes compared with non-athletes, the right ventricular end-diastolic volume was significantly higher, with an area length of 100.3 + 26.9 mL/m2 for the athletes, compared with 69.6 + 14.3 mL/m2 for the non-athletes (P=0.001). There were no significant differences in end-diastolic volume between athletes with and without arrhythmias, however.
But when they looked at right-ventricular end-systolic volume, however, they found that it was significantly higher among the athletes with arrhythmias than those without, at 52.6 + 22.3 vs. 35.5 + 11.2 mL/ m2, respectively (P=0.004).
As a result, the athletes with arrhythmia had a significantly lower right-ventricular ejection fraction, a finding that was consistent across all methods of measurement. In the athletes with arrhythmia, the area length was 49.1 + 10.4%., and in those without rhythm disturbances it was 63.7 + 6.4% (P
They acknowledged that right ventricular biopsy for pathology studies was performed in only five of the athletes with ventricular arrhythmias, and that were was no specific evidence on light microscopy of abnormalities suggestive or arrhythmogenic right ventricular cardiomyopathy.