James Brown, age 11, of Nashua, N.H., for his question:

WHAT IS A CORONARY THROMBOSIS?

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

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 leaves scar tissue in the area surrounding the artery where the clot blocked the blood vessel.