Cardiac remodeling and myocardial late gadolinium enhancement in competitive amateur cyclists: insights from cardiac MRI.

PURPOSE: To evaluate cardiac remodeling and right ventricular insertion point (RVIP) and non-RVIP late gadolinium enhancement (LGE) patterns, and their clinical and performance correlates, in cyclists using MRI.

METHODS: In this prospective study, 66 competitive amateur cyclists (88% male; age 42 ± 13y) and 35 controls (74% males; age 40 ± 13y) underwent 3.0T contrast-enhanced cardiac MRI and cardiopulmonary exercise testing. Cycling history and competitiveness (score:10-70; higher=greater drive) were assessed by questionnaire.

RESULTS: Compared to controls, cyclists showed 'athlete's heart' characteristics, including bi-ventricular enlargement and increased left ventricular (LV) mass (all p < 0.001). Focal non-ischemic myocardial LGE occurred in 19/58 (33%) of male cyclists, predominantly at the RVIP (RVIP LGE, 79%), and inferolateral wall (non-RVIP LGE, 21%). No female cyclists showed LGE. Male cyclists with non-RVIP LGE had higher myocardial mass (90 ± 5 vs. 79 ± 8 g/m2, p = 0.013), reduced RV ejection fraction (RVEF, 47 ± 4% vs. 55 ± 5%, p = 0.031), and elevated high-sensitivity troponin T (8.8 ± 1.7 vs. 5.1 ± 2.0 pg/ml, p = 0.016) compared to those without LGE. Compared to RVIP LGE cyclists, they also had greater LV mass (90 ± 5 vs. 74 ± 10 g/m2, p = 0.001), higher LV end-diastolic volume (133 ± 16 vs. 108 ± 12 ml/m2, p = 0.043) and lower RVEF (47 ± 4% vs. 57 ± 5%, p = 0.011). Cyclists with RVIP LGE had comparable myocardial mass as those without LGE (p = 0.082). LGE presence was not associated with maximal oxygen uptake, exercise systolic blood pressure, cycling history, or competitiveness (all p > 0.05).

CONCLUSION: Nearly one-third of cyclists had focal non-ischemic myocardial LGE, predominantly at the RVIP. Adverse remodeling and reduced function were confined to cyclists with non-RVIP LGE, suggesting a distinct, pathological phenotype.