Heart Disease: Heart Attacks
More than 1 million Americans have heart attacks each year. A heart attack, or myocardial infarction (MI), is permanent damage to the heart muscle. "Myo" means muscle, "cardial" refers to the heart and "infarction" means death of tissue due to lack of blood supply.
What Happens During a Heart Attack?
The heart muscle requires a constant supply of oxygen-rich blood to nourish it. The coronary arteries provide the heart with this critical blood supply. If you have coronary artery disease , those arteries become narrow and blood cannot flow as well as it should. Fatty matter, calcium, proteins and inflammatory cells build up within the arteries to form plaques of different sizes. The plaque deposits are hard on the outside and soft and mushy on the inside.
When the plaque's hard, outer shell cracks (plaque rupture), platelets (disc-shaped particles in the blood that aid clotting) come to the area, and blood clots form around the plaque. If a blood clot totally blocks the artery, the heart muscle becomes "starved" for oxygen. Within a short time, death of heart muscle cells occurs, causing permanent damage. This is called a myocardial infarction (MI), or heart attack.
While it is unusual, a heart attack can also be caused by a spasm of a coronary artery. During coronary spasm, the coronary arteries restrict or spasm on and off, reducing blood supply to the heart muscle (ischemia). It may occur at rest and can even occur in people without significant coronary artery disease .
Each coronary artery supplies blood to a region of heart muscle. The amount of damage to the heart muscle depends on the size of the area supplied by the blocked artery and the time between injury and treatment.
Healing of the heart muscle begins soon after a heart attack and takes about eight weeks. Just like a skin wound, the heart's wound heals and a scar will form in the damaged area. But, the new scar tissue does not contract or pump as well as healthy heart muscle tissue. So, the heart's pumping ability is lessened after a heart attack. The amount of lost pumping ability depends on the size and location of the scar.
What Are the Symptoms of a Heart Attack?
Symptoms of a heart attack include:
- Discomfort, pressure, heaviness, or pain in the chest, arm or below the breastbone
- Discomfort radiating to the back, jaw, throat or arm
- Fullness, indigestion or choking feeling (may feel like heartburn)
- Sweating, nausea, vomiting or
Heart Attack
(Myocardial Infarction)
Medical Authors and Editors: Daniel
Kulick, MD, FACC, FSCAI
and Dennis Lee, MD
Medical Editors: Jay Marks, MD
and William C. Shiel, Jr., MD, FACP, FACR
- ACE Inhibitors - Read about ACE inhibitors like Altace, lisinopril, enalapril, ramparil, Zestril and more. Information includes side effects, drug interactions, and pregnancy safety information.
- Coronary Artery Bypass Graft - Read about heart bypass surgery (coronary artery bypass graft surgery, CABG) including how coronary artery disease is diagnosed, treated, recovery time, risks and complications, and the long term results after CABG.
- Low Blood Pressure - Learn about low blood pressure (hypotension). Low blood pressure is blood pressure below normal and symptoms may include: lightheadedness, dizziness, fainting upon standing (orthostatic hypotension). There are many causes of low blood pressure, and treatment is dependant upon the cause.
Latest Medical News
Heart RSS