Echocardiographic assessment of myocardial performance after prolonged strenuous exercise

To determine the effect of strenuous prolonged exercise on systolicand diastolic left ventricular function, 11 non-elite marathonrunners aged 37±7 years (mean±SD) were studiedbefore and during early recovery from a marathon race. Cavitydimensions, wall thickness, and fractional shortening were computedfrom two-dimensionally guided M-mode echocardiograms. Dopplerleft ventricular inflow tract recordings were analysed for peakearly and late velocities and their ratio. In seven subjects,heart frequency was recorded throughout the race. These subjectsran the marathon at 87±4% of their maximal heart rate.Left ventricular diastolic dimension was slightly reduced atthe end of the race (49·4±4·2 mm to 47·3±5·1mm:P<0·05). Fractional shortening remained unchanged,although blood pressure (P<0·001) and systolic itall stress (P<0·01) were decreased. The left ventricularfilling pattern was unchanged, and the ratio of early to latevelocities remained constant. These results suggest that thefractional shortening was a result of the opposing effects ofchanges in preload and afterload. However, the absence of achange in the end systolic dimension, despite a marked reductionin afterload and the occurrence of septal akinesia in one subjectafter the race could only suggest that strenuous prolonged exercisemay alter mnyocardial performance.