Atropine-induced cardioacceleration and myocardial blood flow in subjects with and without coronary artery disease

Thirty-five patients being studied by coronary cineangiography for diagnosis or evaluation of coronary atherosclerotic occlusive disease had myocardial blood flow determinations at rest and after intravenous administration of atropine sulfate, 1.0 mg. Myocardial blood flow was determined by a coincidence counting system and a single bolus injection of ⁸⁴rubidium chloride.In 10 patients without coronary occlusive disease, heart rate increased by 52 percent and myocardial blood flow by 48 percent (P < 0.001, r = 0.888). In 14 patients with single vessel disease or partial occlusion of two vessels, myocardial blood flow increased by 44 percent and heart rate by 37 percent (P <0.05, r = 0.553). In 11 patients with two or three vessel occlusive disease, heart rate increased by 30 percent whereas myocardial blood flow increased by only 15 percent (r = ?0.172).We conclude that patients with two and three vessel involvement by atherosclerotic occlusive disease are unable to increase nutrient myocardial blood flow in response to atropine-induced Cardioacceleration to the same degree as patients without coronary disease or with less extensive disease. The observation may be of therapeutic importance because of the potential that administration of atropine may have for inducing myocardial ischemia in such patients.