Cardiology: The Lethal Abscess

By far the most common form of heart attack is an occlusion (shutdown) caused by a thrombosis (clot formation) in one of the coronary arteries, which supply blood to the heart's own muscular walls. Physicians have long known that the dangerous clots usually form where a coronary artery is narrowed by a scaly deposit, or "plaque," of chalky, fatty material. But for all its importance, a nagging question has remained unanswered: How does the fatal clot really form?

This week, in the American Journal of Pathology, two San Francisco doctors offer an...