Sometimes the surface of a plaque in a coronary artery ruptures. The rupture releases substances that make platelets stickier, encouraging clots to form on the surface of the plaque. The clot can block the flow of blood through the already-narrowed artery entirely. Without blood, heart muscle tissue starts to die in what's termed a myocardial infarction- a heart attack.

Time is critical during a heart attack. The loss of muscle tissue in a heart attack is permanent unless blood flow can be restored within 1-6 hours, and about half of the people who die of heart attacks die within the first hour after the onset of symptoms. In the U.S., more than 1.5 million people have a heart attack each year. About one third of them are fatal.

More on this topic

Understanding Heart Attacks (VIDEO)
Your Heart Needs Blood
Your Beating Heart
Atherosclerosis & Cholesterol
Angina & Coronary Heart Disease
Heart Attack Symptoms
What Is a Heart Attack?
Risk Factors & Diagnosis
Treating Heart Attacks
Restoring Blood Flow
Rehabilitation

Related Health Centers:

Aneurysm and Stent, Angioplasty, Arrhythmia, Cardiovascular Continuum, Cholesterol and Atherosclerosis, Coronary Bypass Surgery, Heart Attack and Angina, Hypertension, Stroke, Thrombosis and Embolism, Women and Cardiovascular Health