Myocardial work index as a marker for physiologic cardiac remodeling in elite endurance athletes

Endurance athletes are expected to present a cardiac remodeling characterized by eccentric hypertrophy. Differentiation from underlying cardiomyopathy mimicking a similar cardiac remodeling may be challenging. Myocardial work indexes (MWI) have been shown to be useful in distinguishing between physiological adaption and pathological changes in the athletes' heart. However, data on MWI in athletes are scarce. The aim our study is to describe MWI in a cohort of endurance athletes.

We enrolled 153 endurance Olympic athletes (90, 58.8 % male), mean age 26.3 ± 4.1 y.o. and grouped, according to remodeling in eccentric hypertrophy (EH) vs. normal geometry. All underwent cardiopulmonary exercise test (CPET) and transthoracic echocardiography (TTE) with assessment of strain rate and MWI.

Eighty-seven (56.9 %) athletes have EH and 66 (43.1 %) NG. Athletes with EH trained for the same hours/week (p = 0.538). At TTE, MWI did not differ between groups (Global Work Index p = 0.668; Global Constructive Work, p = 0.862; Global Wasted Work p = 0.439 and Global Work Efficiency,p = 0.832). At CPET, Athletes with EH presented higher functional indexes (371.9 ± 101.8 vs 309.6 ± 82.7 W, p < 0.0001; Higher VO2 max, mL/min/kg 59.0 ± 17.1 vs. 51.6 ± 9.3, p = 0.0009) with similar arrhythmic burden. At multivariate analysis, EH was indipendently associated with VO2 max (p = 0.028) and O2 pulse (p = 0.006).

Eccentric remodeling is common and even extreme in endurance athletes and may raise question of differential diagnosis. In this case, MWI could help to differentiate between benign and pathological non-remodeling, allowing for a more tailored approach to athlete evaluation and management.