A depression in left ventricular diastolic filling following prolonged strenuous exercise is associated with changes in left atrial mechanics

Background: Standard marathon running can result in a depression of left ventricular (LV) diastolic function during early recovery. Left atrial (LA) mechanics are integral in maintaining an early diastolic pressure gradient as well as being responsive to changes in LV diastolic function, and therefore the detailed assessment of LA mechanics may provide further insight. The aim of this study was to determine the impact of prolonged strenuous exercise on mechanics of the left atrium and the association with changes in LV diastolic function.

Methods: Myocardial speckle-tracking echocardiograms of the left atrium and left ventricle were obtained prior to, immediately after, and 6 hours after the completion of a marathon (42.2 km) in 17 healthy adult men. Speckle tracking was used to determine peak atrial deformation, early diastolic deformation rate, and contractile function, including atrial activation time. LA volumes throughout the cardiac cycle were also assessed to provide reservoir, conduit, and booster pump volumes. Diastolic assessment of the left ventricle included peak early diastolic strain rate, late diastolic strain rate, and standard indices. Temporal assessment of LV "twist" and "untwist" was also evaluated.

Results: All 17 subjects completed the marathon (mean finishing time, 209 +/- 19 minutes; range, 173-241 minutes). Although contractile function was significantly increased, there was a reduction in early diastolic deformation rate that was correlated with reduced atrial deformation. Atrial activation time was significantly increased after the race. All LV indices of diastolic function were reduced in early diastole, whereas late diastolic function was increased after the race. LV torsion was significantly reduced at end-systole and significantly elevated in the isovolumic period and early diastole, after the race. All indices returned toward baseline at 6 hours after exercise.

Conclusions: This study demonstrates transient changes in LV diastolic relaxation following prolonged exercise that appear to have a direct impact on subsequent LA deformation. The impact of reduced LA preload on these findings and the delay in LA activation time requires further exploration.