[Effect of verapamil on myocardial infarct size estimated by serial 201-thallium single-photon emission tomography].

To investigate the effects of intravenous verapamil (V) in coronary thrombolytic therapy, we serially observed the time course of perfusion of the myocardium by 201-thallium (Tl) SPECT in patients who were successfully reperfused within 6 hours from the onset. 201-Tl SPECT was attempted serially on the 1st-2nd day, the 7th-10th day and 28th-30th day. In addition to this, we calculated the count ratio of radioactivity of 99mTc-PYP (CR) in the infarcted myocardium to sternum to evaluate intracellular uptake of calcium during reperfusion. The infarct size, estimated by % Defect decreased significantly in the patients treated with V, while it remained unchanged in the patients without it. In the patients with V, the left ventricular ejection fraction was more favourable, and exercise-induced ischemia determined by redistribution of 201-Tl SPECT in the chronic phase was found more frequently. CR showed no difference between reperfused myocardium irrespective of the treatment. In conclusion, verapamil was considered to enhance myocardial salvage carried out by reperfusion, and not to affect the influx of intracellular calcium into the injured myocytes.