[Left ventricular function after prolonged exercise].
To determine whether depressed left ventricular (LV) contractile function can occur after exhaustive exercise, echocardiographic studies were performed in eleven athletes before, at the finish (9 minutes) and during recovery (15 hour) after the Biwa Lake Ironman Triathlon (3.2 km Swim, 161 km Bike, 32 km Run). Before racing and during recovery, the studies were performed both at rest and after brief exercise (10-15 minutes). Heart rates after brief exercise were comparable to those attained after racing. Digitized M mode echocardiographic data as to wall thickness, cavity dimension, fractional shortening (FS) and peak circumferential shortening (maxVcf) were obtained. When we compared race finish to pre-race brief exercise, the LV end-diastolic dimension (EDD) was reduced (46 +/- 7 vs 47 +/- 6 mm, less than 0.05) and FS declined (33 +/- 5 vs 39 +/- 6%, p less than 0.05). In spite of reduced wall stress, maxVcf decreased. Individual percent reductions in FS were not correlated with decrease in EDD, but correlated with increases in EDS. Although a persistent reduction in cavity size was observed during recovery, FS and maxVcf returned toward the baseline. The results suggest that prolonged strenuous exercise may result in impaired LV function in part because of a reversible depression in the contractile state.