Shear wave elastography to unmask differences in myocardial stiffness between athletes and sedentary non-athletes.

Aims: Myocardial stiffening naturally occurs with aging and contributes to diastolic dysfunction. Assessing myocardial stiffness non-invasively could improve the sensitivity of diastolic function evaluation in clinical practice. Shear wave (SW) elastography is a non-invasive tool for quantifying myocardial stiffness, where higher SW velocities indicate increased stiffness. We investigated whether SW elastography could detect differences in myocardial stiffness between athletes and sedentary non-athletes and, during exercise, reveal differences in operational stiffness that may indicate diastolic dysfunction.

Methods and results: We enrolled 20 master athletes (median age 60 [IQR 59-66] years) and 17 sedentary non-athletes (median age 58 [IQR 52-71] years). Standard exercise echocardiography revealed no significant differences in diastolic function between the groups. Additionally, ultra-high frame rate imaging was used to measure SW velocities after mitral valve closure (MVC) and aortic valve closure (AVC) at rest and during exercise. At rest, athletes had lower SW velocities after MVC compared to sedentary non-athletes (3.2 ± 0.4 m/s vs. 3.9 ± 0.7 m/s, respectively, P = 0.003). During exercise, SW velocities after AVC significantly increased in sedentary non-athletes but not in athletes (+1.6 ± 1.6 cm/s increase per 1% power output increase vs. 0.0 ± 0.8 cm/s, respectively, P = 0.006). An inverse correlation was found between the increase of SW velocity after AVC during exercise and VO₂max (r = -0.51, P = 0.003).

Conclusion: SW elastography reveals reduced myocardial stiffness in athletes compared to sedentary non-athletes at rest and during exercise, which is not detected by conventional echocardiographic measurements. Exercise-induced changes in SW velocities after AVC may potentially serve as an early marker for detecting diastolic dysfunction.