Left ventricular function and mechanics following prolonged endurance exercise: an update and meta-analysis with insights from novel techniques.

<p>Background</p> <p>The cardiac consequences of undertaking endurance exercise are the topic of recent debate. The purpose of this review is to provide an update on a growing body of literature, focusing on left ventricular (LV) function following prolonged endurance exercise over 2 h in duration which have employed novel techniques, including myocardial speckle tracking, to provide a more comprehensive global and regional assessment of LV mechanics.</p> <p><br></p> <p>Methods</p> <p>Prospective studies were filtered independently following a pre-set criteria, resulting in the inclusion of 27 studies in the analyses. A random-effects meta-analysis was used to determine the weighted mean difference and 95% confidence intervals (CI) of LV functional and mechanical data from pre-to-post-exercise. Narrative commentary was also provided where volume of available evidence precluded meta-analysis.</p> <p><br></p> <p>Results</p> <p>A significant overall reduction in LV longitudinal strain (<em>Ɛ</em>) <em>n</em> = 22 (− 18 ± 1 to − 17 ± 1%; effect size (<em>d</em>) − 9: − 1 to − 0.5%), strain rate <em>n</em> = 10 (SR;<em>d</em> − 0.9: − 0.1.3 to − 0.5 l/s) and twist<em>n</em> = 5 (11.9 ± 2.2 to 8.7 ± 2.2°,<em>d</em> − 1: − 1.6 to − 0.3°) was observed following strenuous endurance exercise (range 120–1740 min) (<em>P</em> < 0.01). A smaller number of studies (<em>n</em> = 4) also reported a non-significant reduction in global circumferential and radial <em>Ɛ</em> (<em>P</em> > 0.05).</p> <p><br></p> <p>Conclusion</p> <p>The meta-analysis and narrative commentary demonstrated that a reduction in LV function and mechanics is evident following prolonged endurance exercise. The mechanism(s) responsible for these changes are complex and likely multi-factorial in nature and may be linked to right and left ventricular interaction.</p>