For reasons that aren't completely understood, plaques may rupture. A thrombus (blood clot) forms on or near the site of the rupture; this is the body's confused attempt to "heal" the injured vessel. Several things can happen. The clot may break away and travel to the carotid arteries of the neck or to the brain as an embolus, where it can cause a stroke. (A thrombus that detaches and travels through the bloodstream is called an embolus.) Another possibility is that the clot remains in place or travels to another location in the heart's coronary arteries. There it may completely block blood flow to a portion of the heart, causing a myocardial infarction: a heart attack. In a heart attack, the lack of blood supply causes heart tissue to actually die. The loss is permanent unless blood flow can be restored quickly, in 1-6 hours.

One-third of all heart attacks are fatal. If the heart attack victim survives, the heart may nevertheless be permanently damaged because dead tissue is replaced by scar tissue. Scar tissue can't pulsate the way healthy heart tissue does. The heart is now unable to pump blood efficiently and, as a consequence, has to work harder to move blood throughout the body. This stresses the weakened heart even more.

Symptoms of Heart Attack

• Pressure or squeezing pain in the center of the chest that lasts for more than a few minutes
• Pain similar to that of angina but that is generally more severe, lasts longer, and doesn't respond to rest or angina medication
• Pain that extends beyond the chest to the shoulder, arm, back, or jaw (referred pain)
• Increasing episodes of chest pain
• Prolonged pain in the upper abdomen
• Shortness of breath
• Heavy pounding of heart
• Sweating
• Sense of impending doom
• Fainting
• Nausea and vomiting

A heart attack is a medical emergency. Anyone who has symptoms of heart attack should obtain emergency medical care immediately.

More on this topic

What is Coronary Bypass Surgery? (VIDEO)
Restoring Flow
Stiff & Narrow
The Consequences of Clots
Testing & Diagnosis
Bypass Background
The Way to Your Heart
New Connections
Recovery from Bypass
Lifestyle for a Healthy Heart

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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