Résumé
BACKGROUND: Numerous studies have reported evidence of cardiac injury associated with transient left ventricular (LV) systolic and diastolic dysfunction after prolonged and strenuous exercise. We used 2D ultrasound speckle tracking imaging to evaluate the effect of an ultralong-duration exercise on LV regional strains and torsion. We speculated that systolic dysfunction after exercise is associated with depressed LV strains and torsion, and diastolic dysfunction results from decreased and delayed untwisting, a key factor of LV suction and early filling. METHODS AND RESULTS: Twenty-three triathletes underwent conventional and speckle tracking imaging echocardiography at rest before and immediately after an ultralong distance triathlon. Measurements included LV longitudinal, circumferential and radial strains, LV rotations, and LV torsion. After the race, LV systolic dysfunction was characterized by a decrease in LV longitudinal, radial, and circumferential strains, especially for apical radial strains (44.6+/-15.1% versus 31.1+/-13.8%, P<0.001). Peak torsion was slightly decreased (8.3+/-5.1 degrees versus 6.4+/-3.9 degrees , respectively, P=0.09) and significantly delayed (91+/-18% versus 128+/-31% of systolic duration, P<0.001) beside end-ejection. Peak untwisting was also depressed and delayed beside isovolumic relaxation. CONCLUSIONS: This study documented major alterations in cardiac strains and torsion after an ultralong distance triathlon. LV systolic strains were depressed but not delayed, whereas twisting was decreased and delayed. This altered pattern hampered the rapid untwisting during isovolumic relaxation phase, reducing LV diastolic suction and early filling.