Objectives: The purpose of this research was to study long-term left ventricular (LV) adaptations in very-high-level endurance athletes.
Background: Knowledge of cardiac changes in athletes, who are at particularly high risk of sudden cardiac death, is mandatory to detect hypertrophic cardiomyopathy (HCM) or dilated (DCM) cardiomyopathy.
Methods: We carried out echocardiographic examinations on 286 cyclists (group A) and 52 matched sedentary volunteers (group C); 148 cyclists participated in the 1995 "Tour de France" race (group A1), 138 in the 1998 race (group A2), and 37 in both (group B).
Results: In groups A, A1, A2, and C, respectively, diastolic left ventricular diameter (LVID) was 60.1 +/- 3.9 mm, 59.2 +/- 3.8 mm, 61.0 +/- 3.9 mm, and 49.0 +/- 4.3 mm (A vs. C and A1 vs. A2, p < 0.0001), and maximal wall thickness (WT) was 11.1 +/- 1.3 mm, 11.6 +/- 1.3 mm, 10.6 +/- 1.1 mm, and 8.6 +/- 1.0 mm (A vs. C and A1 vs. A2, p < 0.0001). Among group A, 147 (51.4%) had LVID >60 mm; 17 of them had also a below normal (<52%) left ventricular ejection fraction (LVEF). Wall thickness exceeded 13 mm in 25 athletes (8.7%) (always <15 mm), 23 with LVID >55 mm. In group B, LVID increased (58.3 +/- 4.8 mm to 60.3 +/- 4.2 mm, p < 0.001) and WT decreased (11.8 +/- 1.2 mm to 10.8 +/- 1.2 mm, p < 0.001) with time.
Conclusions: Over one-half of these athletes exhibited unusual LV dilation, along with a reduced LVEF in 11.6% (17 of 147), compatible with the diagnosis of DCM. Increased WT was less common (always <15 mm) and scarce without LV dilation (<1%), eliminating the diagnosis of HCM. Serial examinations showed evidence of further LV dilation along with wall thinning. These results might have important implications for screening in athletes.