UBC Theses and Dissertations
The effects of endurance training and age on left ventricular rotation Esch, Ben
Recent advances in cardiac ultrasound allow for the effective assessment of left ventricular (LV) rotation. LV rotation makes systole more efficient, and significantly aids diastolic filling. To date little information exists on LV rotation in endurance-trained individuals across the lifespan. Therefore, the purpose of this series of investigations was to describe the effects of endurance training and age on LV rotation. In the first investigation, resting LV rotation was assessed with echocardiography and speckle-tracking analysis in 52 athletes ranging in age from 24-76. Athletes were divided into young (≤ 44 years) and older (> 45 years). Neither peak torsion (Old: 16.8±6.4°; Young: 15.0±4.4°) or peak recoil rate (Old: -127.8±48.2°/s; Young: -106.4±39.6°/s) were significantly different between young and old athletes, suggesting preservation of cardiac function with lifelong exercise training. In an attempt to discern the impact of aging on exercising LV rotation, speckle-tracking analysis was used to compare heart transplant recipients (HTR, age: 61 ± 9 years) with recipient (RM, age: 60 ± 12 years) and donor (DM, age: 35 ± 8 years) age-matched individuals. In response to exercise, DM significantly increased peak torsion and peak recoil rate, whereas RM could not. Despite having a heart 25 years younger, LV rotation in HTR was similar to RM, suggesting accelerated aging of the cardiac allograft. Considering pre-transplant etiology, surgery and medications, it is encouraging that HTR responded similarly to healthy RM. In the third experiment, the relationship between preload reduction with lower body negative pressure (LBNP) and LV recoil was compared in normally active and endurance-trained individuals. The major finding of this investigation was that in response to LBNP, normally active individuals were able to increase LV recoil rate; whereas LV recoil rate slowed in endurance athletes during preload reduction. This training mediated LV rotational difference may be an additional mechanism which can help explain the higher incidence of orthostatic intolerance in athletes. Together, these findings add significantly to the small number of investigations examining LV rotation in endurance-athletes and contribute to the foundation for future experiments in this emerging area of research.
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