Anatomic features in victims of sudden coronary death. Coronary artery pathology.

Study of the detailed pathology of the myocardium and coronary arteries in ambulatory subjects dying suddenly of coronary heart disease shows that they can be divided into two groups. In one group, there is atherosclerosis with a new vascular event involving coronary thrombosis, which initiates acute myocardial ischemia. In the other group, there is chronic high-grade stenosis due to atherosclerosis, but there is no recent vascular change; the myocardium in this group shows scarring from a previously healed infarction acting as a substrate for reentrant ventricular arrhythmias. A study of 168 consecutive cases of sudden coronary death in London showed 73.3% to have had a recent coronary thrombotic lesion, giving a ratio of 2.7:1 for patients with versus patients without new acute myocardial ischemia. The widely differing ratios reported in the literature probably reflect the patterns of case selection. Prodromal pain immediately before the onset of ventricular fibrillation in a patient without previous known coronary disease selects for a thrombotic cause and acute myocardial ischemia. Absence of pain in a patient known to have had a previous infarction selects for a primary arrhythmia on the basis of preexisting myocardial hypertrophy and/or scarring.