Left ventricular twist mechanics during exercise in trained and untrained men

Abstract

Introduction: Left ventricular (LV) twist and untwisting rate (LV twist mechanics) play a crucial role during myocardial deformation. It is suggested that exercise training alters resting LV twist mechanics. However, it is unknown whether LV twist mechanics respond differently during exercise in trained and untrained individuals. Aim: To compare LV twist mechanics in trained and untrained individuals at rest and during exercise. Methodology: 11 trained male runners (Peak oxygen uptake (VO2peak): 46.2 ± 6.1 ml.kg-1.min-1 SD) and 13 untrained healthy males (VO2peak: 36.4 ± 6.4 ml.kg-1.min-1 SD) were examined at rest and during supine cycling exercise at 30%, 40%, and 50% peak power output (PPO). Blood pressure and heart rate (HR) were measured continuously using photoplethysmography. Echocardiographical images were collected at rest and during the last 3 minutes of each exercise stage. Speckle tracking technology was used post-hoc to quantify LV twist mechanics. Results: There were no significant differences between the two cohorts in HR, blood pressure, end-systolic-volume (ESV), cardiac output (CO), LV twist or circumferential strain at rest or during exercise (P > 0.05). However, the trained cohort had a significantly lower LV untwisting rate and sphericity index during exercise, as well as a greater end-diastolic-volume (EDV) and stroke volume (SV) (P < 0.05). Conclusion: In trained and untrained individuals LV twist and circumferential strain are similar at rest and respond similarly to exercise. The lower LV untwisting rate during exercise in trained individuals may reflect a more efficient diastolic function when the cardiovascular system is challenged.

New and Noteworthy • This is the first study to investigate LV twist mechanics in trained and untrained males in response to progressive submaximal exercise. • The novel data in the present study showed LV twist and circumferential strain to respond similarly to exercise in trained and untrained males. However, the trained group was shown to have a significantly lower LV untwisting rate in response to exercise which may reflect a more efficient diastolic function.

Key words Left ventricular, twist, untwisting rate, exercise.