What Is A Heart Attack?
The heart works 24 hours a day, pumping oxygen- and nutrient-rich blood to the
body. Blood is supplied to the heart through its coronary arteries. In coronary
heart disease (CHD), plaques or fatty substances build up inside the walls of
the arteries. The plaques also attract blood components, which stick to the
artery wall lining. Called atherosclerosis, the process develops gradually,
over many years. It often begins early in life, even in childhood.
The fatty buildup or plaque can break open and lead to the formation of a
blood clot that seals the break. The clot reduces blood flow. The cycle of
fatty buildup, plaque rupture, and blood clot formation causes the coronary
arteries to narrow, reducing blood flow.
When too little blood reaches the heart, the condition is called ischemia.
Chest pain, or angina, may occur. The pain can vary in occurrence and be mild
and intermittent, or more pronounced and steady. It can be severe enough to
make normal everyday activities difficult. The same inadequate blood supply
also may cause no symptoms, a condition called silent ischemia.
If a blood clot suddenly cuts off most or all blood supply to the heart, a
heart attack results. Cells in the heart muscle that do not receive enough
oxygen-carrying blood begin to die. The more time that passes without treatment
to restore blood flow, the greater the damage to the heart.
To learn more:
For additional information, please see the following topics in the NHLBI Diseases and Conditions Index:
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