Assessment of cardiac performance with quantitative radionuclide angiocardiography: sequential left ventricular ejection fraction, normalized left ventricular ejection rate, and regional wall motion.

Abstract

Sequential quantitative first pass radionuclide angiocardiograms (RA) were used to measure left ventricular ejection fraction (LVEF) and left ventricular ejection rate (LVER), and to assess regional wall motion (RWM) in the anterior (ANT) and left anterior oblique (LAO) positions. Studies were obtained with a computerized multicrystal scintillation camera suitable for acquiring high count-rate data. Background was determined in a new fashion by selecting frames temporally from the left ventricular region of interest time-activity curve. A representative cardiac cycle was formed by summing together counts over 3-6 cardiac cycles. From this background corrected, high count-rate representative cardiac cycle, LVEF, LVER and RWM were determined. In 22 patients with normal sinus rhythm in the absence of significant valvular regurgitation RA LVEF correlated well with that measured by contrast angiography (r = 0.95). LVER correlated well with LVEF measured at contrast angiography (r = .90) and allowed complete separation of those with normal (LVER = 3.4 .+-. 0.17 s-1) and abnormal (LVER = 1.22 .+-. 0.11 s-1) (P < .001) left ventricular performance. This separation was independent of background. Isoproterenol infusion in 5 normal subjects caused LVER to increase by 81 .+-. 17%; LVEF increased by 10 .+-. 2.1%. RWM was correctly defined in 21/22 patients and 89% of left ventricular segments with abnormal wall motion.