Role of left ventricular untwisting in diastolic dysfunction after long duration exercise

Abstract

Numerous studies have reported that long duration exercise induces transient left ventricular (LV) dysfunction. Using 2D-strain echocardiography, we aimed to describe cardiac mechanics following 2 h of exercise. We focused especially on LV twist since untwisting is crucial in the development of intraventricular pressure gradient, a key element of LV early filling. Twenty healthy males (20-41 years) underwent a resting echocardiography including a 2D-strain evaluation based on velocity vector imaging before and after 2-h of cycling at a moderate intensity. Measurements included LV longitudinal, radial and circumferential strains, and LV rotations and twist. After the prolonged exercise, the depressed diastolic function (peak E: 77.5 ± 11.4 vs. 71.9 ± 10.9, P < 0.01) was associated with a delay in peak untwisting velocity (110 ± 14 vs. 119 ± 14% of systolic duration, P < 0.05), whereas LV peak diastolic strain rates, indexes of LV relaxation, were unchanged. LV global systolic function and LV peak systolic strain rates remained normal after the exercise (fractional shortening: 36.8 ± 2.8 vs. 36.9 ± 5.7, NS). In conclusion, the present study gives new insight into cardiac dysfunction following long duration exercise. It demonstrates that depressed diastolic function is associated with delayed untwisting velocity, but depressed LV relaxation and contractility following exercise remains controversial.