Polypositional postmortem contrast coronarography and pathomorphological analysis were used to study 400 cases of atherosclerotic, postinfarction, arrhythmogenic, and hypertensive heart. High incidence of sudden cardiac death was established in patients with coronary artery ectasia in atherosclerotic heart. In most cases, ectasias were observed in the anterior interventricular branch of the left coronary artery with dominant localization in the second and forth segments. Correlation was found between the maximum incidence of ectasia in the anterior interventricular branch of the left coronary artery and their maximal length, diameter, and bag-shaped appearance. We determined characteristic alterations in cardiac angioarchitectonics reflecting segmentary location of ectasia reflecting inadequacy of coronary circulation and myocardial ischemia leading to ventricular fibrillation and sudden cardiac death.