Heart Attack
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.
Get Help Quickly
Acting fast at the first sign of heart attack symptoms can save your life and limit damage to your heart. Treatment is most effective when started within 1 hour of the beginning of symptoms.
The most common heart attack signs and symptoms are:
Chest discomfort or pain—uncomfortable pressure, squeezing, fullness, or pain in the center of the chest that can be mild or strong. This discomfort or pain lasts more than a few minutes or goes away and comes back.
Upper body discomfort in one or both arms, the back, neck, jaw, or stomach.
Shortness of breath may occur with or before chest discomfort.
Other signs include nausea (feeling sick to your stomach), vomiting, lightheadedness or fainting, or breaking out in a cold sweat.
If you think you or someone you know may be having a heart attack:
start of symptoms.
If your symptoms stop completely in less than 5 minutes, still call your doctor.
Only take an ambulance to the hospital. Going in a private car can delay treatment.
Take a nitroglycerin pill if your doctor has prescribed this type of medicine.
Outlook
Each year, about 1.1 million people in the United States have heart attacks, and almost half of them die. CAD, which often results in a heart attack, is the leading killer of both men and women in the United States.
Many more people could recover from heart attacks if they got help faster. Of the people who die from heart attacks, about half die within an hour of the first symptoms and before they reach the hospital.
The heart is a muscle like any other in the body. It needs blood flow to supply oxygen to allow it to do work. When there isn't enough oxygen, the muscle starts to suffer, and when there is no oxygen, the muscle starts to die.
Heart muscle gets its blood supply from arteries that start in the aorta and run on the surface of the heart, known as the coronary arteries. The right coronary artery supplies the right ventricle of the heart and the inferior (lower) portion of the left ventricle. The left anterior descending coronary artery supplies the majority of the left ventricle, while the circumflex artery supplies the back of the left ventricle.
Over time, cholesterol buildup can occur in these blood vessels in the form of plaque. This narrows the artery and can restrict the amount of blood that can flow through it. If the artery becomes too narrow, it cannot supply enough blood to the heart muscle when it becomes stressed. Just like arm muscles that begin to hurt if you lift too much, or legs that ache when you run too fast; the heart muscle will ache if it doesn't get adequate blood supply. This ache is called angina.
If the plaque ruptures, a small blood clot can form within the blood vessel and acutely block the blood flow. When that part of the heart loses its blood supply completely, the muscle dies. This is called a heart attack, or an MI - a myocardial infarction (myo=muscle +cardial=heart; infarction=death due to lack of oxygen).
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