[Radionuclide determination of the left ventricular ejection fraction under stress: comparison with...

Left ventricular ejection fraction (LVEF) determined by first pass radionuclide (Nucl.) and biplane contrast angiocardiography (Angio.) was compared in 62 patients with suspected coronary artery disease under resting conditions and in 32/62 patients during bicycle ergometry at identical work load. At rest both methods correlated with r = 0.81 with similar heart rates in both determinations. The mean value of LVEF (Nucl.) was lower than the mean value of LVEF (Angio.), at 50 +/- 2 (SE) % and 58 +/- 2% respectively (p less than 0.001). During exercise a significant correlation between the two methods was again found (r = 0.76). This time no difference was detected between the mean values for LVEF (50 +/- 3% [Nucl.] vs 48 +/- 2% [Angio.], n.s.), which may be explained by the higher heart rates during the invasive study (123 +/- 5/min [Angio.] vs. 108 +/- 4/min [Nucl.], p less than 0.001), resulting in a higher degree of ischemia and hence a lower LVEF. The interobserver variability did not differ between the two methods.