Patterns of exercise response in patients with severe left ventricular dysfunction: radionuclide ejection fraction...

To evaluate the exercise response of the severely diseased left ventricle, 13 patients with chronic congestive cardiomyopathy with mean resting ejection fraction (EF) of 18.8 +/- 9.6% underwent maximal supine bicycle exercise with hemodynamic and radionuclide monitoring. Two patterns of exercise response were noted. Group I (n = 7) was characterized by significant (p less than 0.001) increases in stroke work index (SWI) (+52%), stroke volume index (SVI) (+34%), mean arterial pressure (AP) (+23%), and cardiac index (CI) (+119%) and by a decrease in systemic vascular resistance (SVR) (-45% p less than 0.001). In group II (n = 6) there were no significant changes in SWI (-15%), AP (+11%), and SVR (-17%)(; SVI decreased significantly (-14%, p less than 0.05), and the increase in CI, although significant (+27%, p less than 0.01), did not achieve the level of Group I. EF did not change with exercise in either group. There were no significant differences at rest in any of the above variables, and the pulmonary capillary wedge pressures at maximal exercise were similar. We conclude that there are two patterns of exercise response in patients with severe congestive heart failure (CHF) and that these patterns may have important therapeutic and prognostic implications.