Influence of propranolol on uptake of radioiodinated heptadecanoic acid and thallium-201 in the dog heart.

In an experimental study, the influence of propranolol on myocardial uptake of radioiodinated heptadecanoic acid (131I-HDA) and thallium-201 (201Tl) in the dog heart was assessed. Uptake of 131I-HDA and 201Tl was evaluated in ten control dogs and in ten dogs 20 min after IV administration of propranolol (0.15 mg/kg). In both groups, four healthy dogs were studied and six dogs were studied after coronary artery occlusion. It was shown that both total uptake of 131I-HDA and 201Tl did not alter significantly, regardless of significant changes in hemodynamic parameters and total arterial plasma FFA levels. However, distribution of both 131I-HDA and 201Tl was markedly affected by propranolol, since the endocardial to epicardial ratio showed significantly higher values in the ischemic myocardial regions. The results of our study indicate that propranolol (1) preserves myocardial perfusion in the normal and acutely ischemic dog heart, and (2) gives a more favorable distribution in the ischemic myocardial region towards the subendocardial layers.