Effects of gallopamil on iodine-123-phenyl-pentadecanoic acid and thallium 201 uptake in patients with coronary heart disease

Numerous experimental and clinical studies indicated that in the presence of coronary artery stenoses, myocardial thallium-201 and free fatty acid uptake in poststenotic regions is reduced during exercise. The aim of this study was to investigate the effect of the calcium antagonist gallopamil on myocardial thallium-201 and free fatty acid uptake in patients suffering from coronary artery disease. In 6 patients with angiographically proven coronary artery disease--2 patients with 1-vessel, 2 patients with 2-vessel and 2 patients with 3-vessel disease--as well as good left ventricular performance and stable, exerciseinduced angina, quantitative double-tracer scintigraphy was performed. Patients were investigated after a placebo period of 1 week, after oral gallopamil medication for 4 weeks (3 X 50 mg gallopamil daily), and after a double-blind period of 1 week. During symptom-limited exercise, 2 mCi thallium-201 and 5 mCi iodine-123 phenyl-pentadecanoic acid (IPPA) were simultaneously injected intravenously. Immediately after exercise, as well as 1 and 4 hours later, planar images were obtained in ap, 30 degrees LAO and 60 degrees LAO projections. By means of a newly developed computer algorithm, global and regional myocardial tracer uptake as well as IPPA clearance were evaluated. - Gallopamil provoked a decrease of global myocardial thallium-201 and IPPA uptake due to a reduction of myocardial oxygen consumption. Regional thallium-201 and IPPA uptake as well as myocardial IPPA clearance in poststenotic areas tended to rise following gallopamil medication. Thus, in the presence of coronary artery disease, gallopamil provokes an improvement of regional perfusion (dilatation of larger coronary arterioles) as well as an enhanced free fatty acid utilization in reversibly ischemic myocardial regions.