Myocardial Work Indices in Olympic Athletes: Sex-Specific Reference Values and the Impact of Sports Disciplines

Differentiating exercise-induced cardiac remodeling from early dilated cardiomyopathy remains challenging in athletes, as conventional echocardiographic parameters may overlap in cardiomyopathies and physiologic remodeling. Myocardial work indices (MWIs) have been proposed as a promising tool to improve characterization of physiologic remodeling and eventually help in this distinction. However, reference values in athletic populations are currently lacking.

The aim of this study was to define sex-specific and sport-independent reference values for MWIs in a large cohort of Olympic athletes.

Six hundred sixty-two Olympic athletes (51.7% male, mean age 25.5 ± 5.3 years) underwent standardized preparticipation cardiovascular screening, including comprehensive transthoracic echocardiography with two-dimensional speckle-tracking. Global myocardial work index (GWI), constructive work (GCW), wasted work (GWW), and work efficiency (GWE) were calculated using noninvasive left ventricular pressure-strain loops. Athletes were categorized into power, skill, endurance, and mixed disciplines. Sex- and discipline-specific comparisons were performed, reference values were derived using the 2.5th to 97.5th percentiles, and associations with age were explored.

In the overall cohort, mean GWI was 1,806.1 ± 250 mm Hg%, GCW 2,188.9 ± 282 mm Hg%, GWW 85.8 ± 42.4 mm Hg%, and GWE 95.7% ± 2.0%. Global myocardial work index and GCW did not differ between male and female patients, whereas male patients showed higher GWW (91.5 ± 45.7 vs 79.7 ± 37.7 mm Hg%, P = .0008) an d slightly lower GWE (95.4% ± 2.3% vs 95.9% ± 1.7%, P = .0004). No significant differences in MWI were observed across sport disciplines. Segmental analysis revealed sex-related differences mainly in basal and mid-left ventricular segments. Age showed only weak, clinically negligible associations with MWI. Proposed limit thresholds were 1,346.7 mm Hg% for GWI, 1,656.1 mm Hg% for GCW, GWW >206.8 mm Hg% in male patients and >174 mm Hg% in female patients, and GWE <91% in male patients and <92% in female patients.

In Olympic athletes, myocardial work is largely independent of sport discipline and age, while sex-specific differences are driven by myocardial efficiency and wasted work. This study establishes sport-independent, sex-specific reference values and preliminary thresholds for MWI, observed in a large cohort of elite athletes, that may help in guiding diagnosis when evaluating doubtful cases of cardiac remodeling.