Assessment of the acute effect of trapidil on cardiac hemodynamics by multi-gated blood pool scintigraphy.

Multi-gated blood pool scintigraphy, a method of clinically proven usefulness for the noninvasive evaluation of cardiac hemodynamics, was used to evaluate the efficacy of trapidil. The longitudinal image of the left ventricle was taken using a gammaray camera equipped with a 30°C slant hole collimator (Siemens model ZLC 75), and the collimator was set in the cranio-caudal direction with amodified LAO. The R waves on the ECG and the second sound on the phonocardiogram were used as synchronizing signals to clarify the target image. The ADAC system II nucleomedical data processor was used for processing and statistical analysis of the data. Ten subjects (9 men and 1 woman at the mean age of 64 years) were injected iv with 100 mg of trapidil over 2 minutes, and the scintigram was taken from immediately after the iv injection. The following results suggested the positive inotropic action with trapidil: 1. lowering of body blood pressure and increase in heart rate (P<0.001); 2. increase in the left ventricular ejection fraction (P<0.01), and increase in cardiac index (P<0.01); 3. increase in maximum left ventricular ejection velocity (P<0.05) and increase in the maximum left ventricular filling velocity (N. S.); 4. increase in the left ventricular work index (P<0.05); and 5. decrease in total systemic vascular resistance (P<0.01).