This volume represents a part of the scientific proceedings of the Sixth Annual Meeting of the American Section of the International Society for Heart Research that was held in Oklahoma City from September 13-15, 1984. The chapters have been grouped according to the content of invited symposia on cardiovascular topics ranging from electrophysiology, autonomic control of the circulation, aging of the myocardium, mechanisms of cardiovascular injury, cultured heart cell studies, etc. Abstracts of all the papers presented at this meeting are included in Volume 16 (Supp. 1) of the Journal of Molecular and Cellular Cardiology. Since our understanding of the pathobiology of cardiovascular injury requires integrating knowledge from both basic and clinical sciences, the information presented in this volume extends from fundamental biochemical processes to pharmacological agents required to treat complex cardiac arrhythmias. At the molecular level, the structural lipids of the sarcolemma may be altered during myocardial ischemia; the role of free radicals in this process is one emerging area of active study. At the subcellular level, plasma membranes provide the anatomical basis for maintenance of optimal potentials of excitable cells; the anatomy and physiology of the sarcolemma ultimately determines the response to drugs and metabolic perturbants. At the cellular level, much progress has been made in our understanding of cultured and adult myocytes during ischemia and hypoxia; in particular, the electrophysiology of these model systems is well understood and several chapters address this approach.