Myocardial Work Efficiency in Physiologic Left Ventricular Hypertrophy of Power Athletes

Abstract

Aims: The athlete's heart in power training is characterized by physiologic concentric remodeling. Our aim was to analyze left ventricular (LV) myocardial deformation and contractile reserve (CR) in top-level power athletes (PA) at rest and during exercise and their possible correlations with functional capacity. Methods: Standard echo, lung ultrasound, and LV 2D speckle-tracking strain were performed at rest and during exercise in PA and in age- and sex-comparable healthy controls. Results: 250 PA (male: 62%; 33.6 ± 4.8 years) and 180 age- and sex-comparable healthy controls were enrolled. LV ejection fraction (EF) at baseline was comparable between the two groups, while LV global longitudinal strain (GLS) was reduced in PA (GLS: −17.8 ± 2.4 in PA vs. −21.9 ± 3.8 in controls; P < 0.01). Conversely, myocardial work efficiency (MWE) did not show significant difference between the two groups (94.4 ± 3.2 in PA vs. 95.9 ± 4.6% in controls; P NS). At peak exertion during exercise stress echocardiography (ESE), PA showed better exercise capacity and peak VO2 consumption (51.6 ± 10.2 in EA vs. 39.8 ± 8.2 mL/Kg/min in controls, P < 0.0001), associated with augmented pulmonary artery systolic pressure (PASP). By multivariable analysis, MWE at rest was the most predictive factor of maximal watts (P < 0.0001), peak VO2, (P < 0.0001), PASP (P < 0.001), and number of B-lines (P < 0.001), all measured at peak effort. Conclusions: In power athletes, MWE showed less load dependency than GLS. Normal resting values of MWE in PA suggest a physiological LV remodeling, associated with a better exercise capacity and preserved CR during physical stress.