Reduced myocardial strain of interventricular septum among male amateur marathon runners: a cardiac magnetic resonance study.

OBJECTIVES: To analyze the long-term effect of multiple marathons on cardiac structure and function in amateur marathon runners compared with healthy controls. DESIGN: Cross-sectional study using male amateur marathon runners (n = 32) and age-matched cohort of male healthy controls (n = 12). METHODS: A total of 32 male amateur marathon runners (age 44 ±â€¯7 years) and 12 male healthy controls (age 42 ±â€¯8 years) underwent cardiac magnetic resonance (CMR). The relevant parameters of cardiac structure and function were studied employing feature-tracking strain analysis. RESULTS: Amateur marathon runners showed lower heart rates, body mass index and body surface area. The left ventricular (LV) mass index, LV end-diastolic volume index and right ventricular end-systolic volume index were significantly higher in amateur marathon runners compared with healthy controls. Furthermore, walls of interventricular septum (IVS) in amateur marathon runners were thicker than healthy controls. There was no significant difference between two groups in the global myocardial strain (MS) in LV. However, the segmental radial and circumferential strains of the LV were lower in amateur marathon runners compared to healthy controls, specifically in the 8th and 9th segments. Finally, we also found as the total running intensity increased, so did global longitudinal strain. CONCLUSIONS: We reported higher wall thickness and lower regional radial and circumferential strain in the IVS region in amateur marathon runners, suggesting that prolonged and high-intensity exercise may cause cardiac remodeling. Further studies are needed to investigate whether this is an adaptive or maladaptive change in amateur marathon runners.