Left ventricular potentiation at a reduced exercise level: a cause of false-negative radionuclide ventriculograms

During exercise radionuclide ventriculography (RVG), many patients cannot maintain peak workload for acquisition of more than a left anterior oblique view. To acquire further views, the workload may have to be reduced. In this study of 16 normals and 20 patients with coronary disease, the workload at peak exercise was reduced by approximately 40%. By paired t-test analysis, there was a rise in the left ventricular ejection fraction (LVEF) in patients with coronary disease from the peak exercise workload to the reduced workload level (postpeak) (52.4 +/- 15.3 to 59.3 +/- 13.7, P = .0001). There was also improvement in LVEF in the normals at the postpeak workload (71.3 +/- 11.7 to 75.1 +/- 13.7, P = .05). Of five coronary disease patients with exercise-induced wall motion abnormalities, four returned to baseline motion at the reduced exercise levels. Partial workload reduction can lead to an increase in LVEF and improvement in wall motion and thus, may result in false-negative studies.