Hemodynamics at rest and during supine and sitting bicycle exercise in patients with coronary artery disease.

To access left ventricular function and compare pulmonary capillary wedge pressure and left ventricular end-diastolic pressure in the supine and sitting positions, 20 men with angina pectoris secondary to coronary artery disease underwent hemodynamic studies at rest and during exercise in the two positions. At rest the values for cardiac index, stroke index, systolic ejection rate index and left ventricular stroke work index were lower in the sitting position; heart rate, left ventricular end-diastolic pressure and pulmonary capillary wedge pressure were similar in the two positions. All patients experienced angina during both exercise periods. At angina during supine exercise, stroke index, systolic ejection rate index and left ventricular stroke work index did not increase significantly from the resting values. In contrast, during sitting exercise, significant increases in these variables were observed. Comparison of data during exercise revealed higher values for heart rate, mean systemic pressure, cardiac index, systolic ejection rate index, left ventricular stroke work index and rate-pressure product and lower values for mean pulmonary capillary wedge pressure (20 +/- 3 versus 27 +/- 3 [mean +/- standard error of the mean] mm Hg, P is less than 0.001), and left ventricular end-diastolic pressure (24+/- 3 versus 31 +/- 3 mm Hg, P is less than 0.02) in the sitting position; stroke index and S-T segment depression were similar during the two exercise periods. Four patients had insignificant increases in left ventricular filling pressure during both exercise periods. Of the 16 patients with abnormal left ventricular filling pressure during supine exercise, only 10 had a similar response during exercise in the sitting position. There was a good correlation between left ventricular end-diastolic pressure and mean pulmonary capillary wedge pressure at rest and during exercise in the two postures.