Hemodynamics at rest and during supine and sitting bicycle exercise in normal subjects

Abstract

To assess left ventricular function and to compare mean pulmonary wedge pressure and left ventricular end-diastolic pressure in the supine and sitting positions, 10 patients without demonstrable cardiovascular disease underwent hemodynamic studies at rest and during exercise In the two positions. At rest the values for heart rate were higher and the values for cardiac index, stroke index, left ventricular stroke work Index, mean pulmonary capillary wedge pressure and left ventricular end-diastolic pressure were lower in the sitting position. During both supine and sitting exercise left ventricular end-diastolic pressure, cardiac index, stroke index and left ventricular stroke work index increased significantly from the resting values. Comparison of data during exercise revealed higher values for heart rate and rate-pressure product and lower values for pulmonary capillary wedge pressure, left ventricular end-dlastollc pressure and stroke index in the sitting position; systolic and mean systemic pressure, cardiac index and left ventricular stroke work Index were similar during the two exercise periods. When absolute changes from rest to exercise were compared, the Increase In heart rate, systolic blood pressure, pulmonary capillary wedge pressure, left ventricular end-dlastollc pressure, cardiac index, stroke index, and left ventricular stroke work index were similar In the two positions. There was a good correlation between left ventricular end-diastolic pressure and pulmonary capillary wedge pressure at rest and during exercise in the two postures.