Abstract
Marathon runners (MTH) and patients with mitral regurgitation (MR) exhibit left ventricular (LV) overload, and LV geometric changes in these groups have been reported. In this study, right ventricular (RV) adaptation to chronic volume overload was evaluated in MTH and MR and normal controls together with interventricular septal remodeling and tricuspid annulus (TA) motion. A total of 60 age-matched subjects (including 19 MTH, 17 isolated chronic compensated MR patients, and 24 normal subjects) underwent conventional cine and tagged cardiac magnetic resonance imaging. Myocardial strain and curvature were computed on the interventricular septum and RV free wall. A dual-propagation technique was applied to construct RV volume-time curves for a single cardiac cycle. Similarly, the TA was tracked throughout the cardiac cycle to create displacement over time curve. Septal curvature was significantly lower in MTH and MR compared to controls. No significant differences in RV free-wall strain or RV ejection fraction were noted among the three groups. However, longitudinal TA excursion was significantly higher in MTH compared to controls (p = 0.0061). The peak late diastolic TA velocity in MR was significantly faster than MTH (p = 0.0031) and controls (p = 0.020). Increased TA kinetics allows for improved RV performance in MTH. Septal remodeling was observed in both MR and MTH, therefore a direct relationship of septal remodeling to TA kinetics in athlete's heart could not be elucidated in this study.
Highlights
The left ventricle undergoes remodeling in response to sustained changes in left ventricular (LV) pressure or volume load
Septal curvature was significantly lower in marathon runners (MTH) and mitral regurgitation (MR) compared to controls
No significant differences in right ventricular (RV) free-wall strain or RV ejection fraction were noted among the three groups
Summary
The left ventricle undergoes remodeling in response to sustained changes in left ventricular (LV) pressure or volume load. We used cardiac magnetic resonance (CMR) imaging to study LV changes in marathon runners (MTH), where the dilated left ventricle maintains an ellipsoid shape, and in mitral regurgitation (MR), where the dilated left ventricle becomes more spherical [1]. The interventricular septum (IVS) allows for direct interaction of left and right ventricles and transmits systolic and diastolic forces between the ventricles. Previous studies [2,3,4,5] have shown that the deleterious effects of LV dilation in severe chronic organic MR on the structure and function of the right ventricle, leading to compression, flattening, and the consequential impairment of Abbreviations: IVS, interventricular septum; MR, mitral regurgitation; MTH, marathon runners; RV, right ventricular; TA, tricuspid annulus; VTC, volume-time curve. Right ventricular (RV) adaptation to chronic volume overload was evaluated in MTH and MR and normal controls together with interventricular septal remodeling and tricuspid annulus (TA) motion
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