Key role of left ventricular untwisting in endurance cyclists at onset of exercise.
Fiche publication
Date publication
septembre 2021
Journal
Journal of applied physiology (Bethesda, Md. : 1985)
Auteurs
Membres identifiés du Cancéropôle Est :
Pr TORDI Nicolas
Tous les auteurs :
Izem O, Mourot L, Tordi N, Grandperrin A, Obert P, Rupp T, Nottin S
Lien Pubmed
Résumé
The rise in oxygen consumption during the transition from rest to exercise is faster in those who are endurance-trained than those who have sedentary lifestyles, partly due to a more efficient cardiac response. However, data regarding this acute cardiac response in trained individuals are limited to heart rate (HR), stroke volume and cardiac output. Considering this, we compared cardiac kinetics, including left ventricular (LV) strains and twist/untwist mechanics, between endurance-trained cyclists and their sedentary counterparts. Twenty young, male, trained cyclists and 23 untrained participants aged 18-25 years performed five similar constant workload exercises on a cyclo-ergometer (target HR: 130 bpm). During each session, LV myocardial diastolic and systolic linear strains, as well as torsional mechanics, were assessed using speckle-tracking echocardiography. Cardiac function was evaluated every 15s during the first minute and every 30s thereafter, until 240s. Stroke volume increased during the first 30-45s in both groups, but to a significantly greater extent in trained cyclists (31% vs 24%). Systolic parameters were similar in both groups. Transmitral peak filling velocity and peak filling rate responded faster to exercise and with greater amplitude in trained cyclists. Left ventricular filling pressure was lower in the former, while LV relaxation was greater, but only at the base of the left ventricle. Basal rotation and peak untwisting rate responded faster and to a greater extent in the cyclists. This study provides new mechanical insights into the key role of LV untwisting in the more efficient acute cardiac response of endurance-trained athletes at onset of exercise.
Mots clés
2D-strain echocardiography, Endurance-trained athletes, LV strain kinetics, LV untwisting, exercise
Référence
J Appl Physiol (1985). 2021 Sep 30;: