Effect of Sympathetic Stimulation and Blockade in Patients with Angina Pectoris

A Clinical Conference in Cardiology from the University of Kentucky Medical Center, Lexington, Kentucky

Dr. Gettes: We have presented three patients with angina pectoris in whom the S-T segment abnormalities of coronary insufficiency could be induced by the infusion of catecholamines. We have reviewed the factors which regulate coronary blood flow and have stressed the importance of the myocardial oxygen requirement in this regulation. We have considered the mechanisms by which the catecholamines. increase myocardial oxygen requirements and have shown that the product of heart rate and blood pressure can be used at the bedside to assess a change in the myocardial oxygen requirement. Finally, we have reviewed our experiences with the beta adrenergic blocking agent, propranolol, in the treatment of angina pectoris and have confirmed the therapeutic effectiveness of the drug. However, we were unable to ascribe the propranolol induced changes in the characteristics of the anginal attack to a critical decrease in myocardial oxygen requirement.