Rapid ventricular filling in left ventricular hypertrophy: I. Physiologic hypertrophy

The effects of endurance training on the diastolic properties of the left ventricle were examined by comparing left ventricular filling rates in 11 male distance runners and 12 age-matched nonathletic control subjects selected to have nearly similar heart rates at rest. Maximal oxygen consumption was 69 +/- 11 ml/kg-min for the athletes and 48 +/- 8 ml/kg X min for the control subjects (p less than 0.001). Left ventricular end-diastolic dimension, posterior wall thickness and mass were determined by echocardiography, and average left ventricular filling rate was determined with a nonimaging scintillation probe. Electrocardiographic voltage was significantly greater in the athlete group than in the control group (sums of the voltages of the S wave in lead V1 and the R wave in lead V5 were 40 +/- 10 and 26 +/- 7 mV, respectively) (p less than 0.001), whereas ejection fraction was similar in the two groups. Despite a modest degree of left ventricular hypertrophy in the athlete group compared with the control group (left ventricular mass index 127 +/- 30 and 82 +/- 13 g/m2, respectively) (p less than 0.001), the average left ventricular filling rate was similar in the two groups (2.53 +/- 0.34 versus 2.38 +/- 0.29 end-diastolic counts/s, p = NS). There was no trend for the athletes with a higher left ventricular mass to exhibit a slower filling rate. These findings demonstrate that unlike pathologic hypertrophy associated with chronic hemodynamic over-loading, physiologic left ventricular hypertrophy is not accompanied by slowed left ventricular diastolic filling.