Virgil McGuire, age 14, of  Rutland, Vt., for his question:

WHAT IS A CORONARY THROMBOSIS?

A coronary thrombosis is a condition in which a clot blocks the passage of blood in the artery of the heart. This condition is also called a heart attack, a coronary occlusion or a myocardial infraction.

Symptoms of a coronary thrombosis include severe chest pain, shortness of breath, vomiting and weak and rapid pulse.

The chest pain felt during a coronary thrombosis is called angina pectoris.

A coronary thrombosis can cause death. If the patient survives, the condition can leave scar tissue in the area surrounding the artery where the clot blocked the blood vessel. Many people make complete recoveries from heart attacks.