What Is Heart Attack?
A heart attack occurs when blood flow to a section of heart muscle becomes blocked. If the flow of blood isn’t restored quickly, the section of heart muscle becomes damaged from lack of oxygen and begins to die.
Heart attack is a leading killer of both men and women in the United States. But fortunately, today there are excellent treatments for heart attack that can save lives and prevent disabilities. Treatment is most effective when started within 1 hour of the beginning of symptoms. If you think you or someone you’re with is having a heart attack, call 9–1–1 right away.
Overview
Heart attacks occur most often as a result of a condition called coronary artery disease (CAD). In CAD, a fatty material called plaque (plak) builds up over many years on the inside walls of the coronary arteries (the arteries that supply blood and oxygen to your heart). Eventually, an area of plaque can rupture, causing a blood clot to form on the surface of the plaque. If the clot becomes large enough, it can mostly or completely block the flow of oxygen-rich blood to the part of the heart muscle fed by the artery.
Figure A is an overview of a heart and coronary artery showing damage (dead heart muscle) caused by a heart attack. Figure B is a cross-section of the coronary artery with plaque buildup and a blood clot.
During a heart attack, if the blockage in the coronary artery isn’t treated quickly, the heart muscle will begin to die and be replaced by scar tissue. This heart damage may not be obvious, or it may cause severe or long-lasting problems.
Severe problems linked to heart attack can include heart failure and life-threatening arrhythmias (irregular heartbeats). Heart failure is a condition in which the heart can’t pump enough blood throughout the body. Ventricular fibrillation is a serious arrhythmia that can cause death if not treated quickly.
What is the Causes a Heart Attack?
Most heart attacks occur as a result of coronary artery disease (CAD). CAD is the buildup over time of a material called plaque on the inner walls of the coronary arteries. Eventually, a section of plaque can break open, causing a blood clot to form at the site. A heart attack occurs if the clot becomes large enough to cut off most or all of the blood flow through the artery.
The illustration shows a normal artery with normal blood flow (figure A) and an artery containing plaque buildup (figure B).
The blocked blood flow prevents oxygen-rich blood from reaching the part of the heart muscle fed by the artery. The lack of oxygen damages the heart muscle. If the blockage isn’t treated quickly, the damaged heart muscle begins to die.
Heart attack also can occur due to problems with the very small, microscopic blood vessels of the heart. This condition is called microvascular disease. It’s believed to be more common in women than in men.
Another less common cause of heart attack is a severe spasm (tightening) of a coronary artery that cuts off blood flow through the artery. These spasms can occur in coronary arteries that don’t have CAD. It’s not always clear what causes a coronary artery spasm, but sometimes it can be related to:
* Taking certain drugs, such as cocaine
* Emotional stress or pain
* Exposure to extreme cold
* Cigarette smoking
The animation below shows how a heart attack occurs. Click the “start” button to play the animation. Written and spoken explanations are provided with each frame. Use the buttons in the lower right corner to pause, restart, or replay the animation, or use the scroll bar below the buttons to move through the frames.
How Is a Heart Attack Treated?
Early treatment can prevent or limit damage to the heart muscle. Acting fast, at the first symptoms of heart attack, can save your life. Medical personnel can begin diagnosis and treatment even before you get to the hospital.
Certain treatments are usually started right away if a heart attack is suspected, even before the diagnosis is confirmed. These include:
* Oxygen
* Aspirin to prevent further blood clotting
* Nitroglycerin, to reduce the workload on the heart and improve blood flow through the coronary arteries
* Treatment for chest pain
Once the diagnosis of heart attack is confirmed or strongly suspected, treatments to try to restore blood flow to the heart are started as soon as possible. Treatments include medicines and medical procedures.
Medicines
A number of different kinds of medicines may be used to treat heart attack. They include the following.
Thrombolytic Medicines
These medicines (also called clot busters) are used to dissolve blood clots that are blocking the coronary arteries. To be most effective, these medicines must be given within 1 hour after the start of heart attack symptoms.
Beta Blockers
These medicines decrease the workload on your heart. Beta blockers also are used to relieve chest pain or discomfort and to help prevent additional heart attacks. Beta blockers also are used to correct arrhythmias (irregular heartbeats).
Angiotensin-Converting Enzyme (ACE) Inhibitors
These medicines lower blood pressure and reduce the strain on your heart. They also help slow down further weakening of the heart muscle.
Anticoagulants
These medicines thin the blood and prevent clots from forming in your arteries.
Antiplatelet Medicines
These medicines (such as aspirin and clopidogrel) stop platelets (a type of blood cell) from clumping together and forming unwanted clots.
Other Medicines
Medicines may also be given to relieve pain and anxiety, and to treat arrhythmias, which often occur during a heart attack.
Medical Procedures
If medicines can’t stop a heart attack, medical procedures—surgical or nonsurgical—may be used.These procedures include the following.
Angioplasty
This nonsurgical procedure can be used to open coronary arteries that are blocked by a blood clot. During angioplasty, a catheter (a thin, flexible tube) with a balloon on the end is threaded through a blood vessel to the blocked coronary artery. Then, the balloon is inflated to push the plaque against the wall of the artery. This widens the inside of the artery, restoring blood flow.
During angioplasty, a small mesh tube called a stent may be put in the artery to help keep it open. Some stents are coated with medicines that help prevent the artery from becoming blocked again.
Coronary Artery Bypass Grafting
Coronary artery bypass grafting is a surgery in which arteries or veins are taken from other areas of your body and sewn in place to bypass (that is, go around) blocked coronary arteries. This provides a new route for blood flow to the heart muscle.
Treatment After You Leave the Hospital
Most people spend several days in the hospital after a heart attack. When you leave the hospital, treatment doesn’t stop. At home, your treatment may include daily medicines and cardiac rehabilitation (rehab). Your doctor may recommend lifestyle changes, including quitting smoking, losing weight, changing your diet, and increasing your physical activity, to lower your chances of having another heart attack.
Cardiac Rehabilitation
Your doctor may prescribe cardiac rehab to help you recover from a heart attack and to help prevent another heart attack. Almost everyone who has had a heart attack can benefit from rehab. The heart is a muscle, and the right exercise will strengthen it.
But cardiac rehab isn’t only about exercise. It also includes education, counseling, and learning about reducing your risk factors. Rehab will help you learn the best way to take care of yourself after having a heart attack and how to prevent having another one.
The cardiac rehab team may include doctors (your family doctor, a cardiologist, and/or a surgeon), nurses, exercise specialists, physical and occupational therapists, dietitians, and psychologists or other behavioral therapists.