The normal right ventricular response to supine exercise.
Nine normal, healthy young males performed graded, maximal supine bicycle exercise with monitoring of hemodynamic and gated blood pool parameters. Right ventricular ejection fraction (RVEF) was greater than 0.45 in all acquisitions at rest (mean +/- SD = 0.53 +/- 0.05) and increased greater than 0.05 in all subjects with maximal exercise (mean +/- SD = 0.69 +/- 0.06 at stage 4). There was a very close correspondence between RV and LV stroke counts from the radionuclide angiograms at rest and all exercise levels in all patients. Cardiac output changes by radionuclide data from the RV correlated closely with those obtained by the Fick technique. Multivariate analysis of RVEF vs pulmonary artery pressure, total pulmonary resistance, and heart rate showed that RVEF was inversely related to total pulmonary resistance in these patients (n = 43 acquisitions, r = 0.61, RVEF = 0.75 -- 0.001 TPR in dynes-sec/cm5 Sy.x = 0.07) and positively related to heart rate (n = 43, 4 = 0.78, RVEF = 0.34 + 0.0025 x HR Sy.x = 0.05). RVEF was not significantly related to the other hemodynamic parameters. These results suggest that in normal subjects RV systolic function is afterload-dependent and that total pulmonary resistance may be a suitable afterload index. The results emphasize that heart rate must be considered when comparing RVEF changes.
D000328:Adult; D001794:Blood Pressure; D002302:Cardiac Output; D003201:Computers; D005080:Exercise Test; D006339:Heart Rate; D006352:Heart Ventricles / Q000000981:diagnostic imaging; D006439:Hemodynamics; D006801:Humans; D008297:Male; D010101:Oxygen Consumption; D011877:Radionuclide Imaging; D013318:Stroke Volume; D013599:Systole; D016276:Ventricular Function