A heart attack happens when the flow of oxygen-rich blood to a section of heart muscle suddenly becomes blocked and the heart can’t get oxygen. If blood flow isn’t restored quickly, the section of heart muscle begins to die.
Heart attack treatment works best when it’s given right after symptoms occur. If you think you or someone else is having a heart attack, even if you’re not sure, call 9–1–1 right away.
Overview
Heart attacks most often occur as a result of coronary heart disease (CHD), also called coronary artery disease. CHD is a condition in which a waxy substance called plaque builds up inside the coronary arteries. These arteries supply oxygen-rich blood to your heart.
When plaque builds up in the arteries, the condition is called atherosclerosis. The buildup of plaque occurs over many years.
Eventually, an area of plaque can rupture (break open) inside of an artery. This causes a blood clot to form on the plaque's surface. If the clot becomes large enough, it can mostly or completely block blood flow through a coronary artery.
If the blockage isn't treated quickly, the portion of heart muscle fed by the artery begins to die. Healthy heart tissue is replaced with scar tissue. This heart damage may not be obvious, or it may cause severe or long-lasting problems.
A less common cause of heart attack is a severe spasm (tightening) of a coronary artery. The spasm cuts off blood flow through the artery. Spasms can occur in coronary arteries that aren't affected by atherosclerosis.
Heart attacks can be associated with or lead to severe health problems, such as heart failure and life-threatening arrhythmias.
Heart failure is a condition in which the heart can't pump enough blood to meet the body's needs. Arrhythmias are irregular heartbeats. Ventricular fibrillation is a life-threatening arrhythmia that can cause death if not treated right away.
Don't Wait--Get Help Quickly
Acting fast at the first sign of heart attack symptoms can save your life and limit damage to your heart. Treatment works best when it's given right after symptoms occur.
Many people aren't sure what's wrong when they are having symptoms of a heart attack. Some of the most common warning symptoms of a heart attack for both men and women are:
Chest pain or discomfort. Most heart attacks involve discomfort in the center or left side of the chest. The discomfort usually lasts more than a few minutes or goes away and comes back. It can feel like pressure, squeezing, fullness, or pain. It also can feel like heartburn or indigestion.
Upper body discomfort. You may feel pain or discomfort in one or both arms, the back, shoulders, neck, jaw, or upper part of the stomach (above the belly button).
Shortness of breath. This may be your only symptom, or it may occur before or along with chest pain or discomfort. It can occur when you are resting or doing a little bit of physical activity.
Other possible symptoms of a heart attack include:
Breaking out in a cold sweat
Feeling unusually tired for no reason, sometimes for days (especially if you are a woman)
Nausea (feeling sick to the stomach) and vomiting
Light-headedness or sudden dizziness
Any sudden, new symptom or a change in the pattern of symptoms you already have (for example, if your symptoms become stronger or last longer than usual)
Not all heart attacks begin with the sudden, crushing chest pain that often is shown on TV or in the movies, or other common symptoms such as chest discomfort. The symptoms of a heart attack can vary from person to person. Some people can have few symptoms and are surprised to learn they've had a heart attack. If you've already had a heart attack, your symptoms may not be the same for another one.
What is the difference between a heart attack and a cardiac arrest?
A cardiac arrest happens when your heart stops pumping blood around your body. Although a heart attack can result in a cardiac arrest, they are two different things.
Someone who has had a cardiac arrest will be unconscious and won’t be breathing normally. If you see someone having a cardiac arrest, you can increase the person's chances of survival by phoning 999 and giving them immediate CPR.
Why do heart attacks happen?
Most heart attacks are caused by coronary heart disease. Coronary heart disease (CHD) is when your coronary arteries (the arteries that supply your heart muscle with oxygen-rich blood) become narrowed by a gradual build-up of fatty material within their walls.
If a piece of this fatty material (atheroma) breaks off it may cause a blood clot (blockage) to form. If it blocks your coronary artery and cuts off the supply of oxygen-rich blood to your heart muscle, this is a heart attack.
You might also hear a heart attack called acute coronary syndrome, myocardial infarction (MI) or coronary thrombosis.
Other rarer causes of a heart attack include spontaneous coronary artery dissection (SCAD) where one or more of the coronary arteries tear.
It is important to stress that not everyone experiences severe chest pain; the pain can often be mild and mistaken for indigestion.
It is the combination of symptoms that is important in determining whether a person is having a heart attack, and not the severity of chest pain.
Coronary heart disease (CHD) is the leading cause of heart attacks. CHD is a condition in which coronary arteries (the major blood vessels that supply blood to the heart) get clogged up with deposits of cholesterol. These deposits are called plaques.
Before a heart attack, one of the plaques ruptures (bursts), causing a blood clot to develop at the site of the rupture. The clot may then block the supply of blood running through the coronary artery, triggering a heart attack.
Your risk of developing CHD is increased by:
smoking
a high-fat diet
diabetes
high cholesterol
high blood pressure
being overweight or obese
Recovery
The time it takes to recover from a heart attack will depend on the amount of damage to the heart muscle. Some people are well enough to return to work after two weeks. Other people may take several months to recover. The recovery process aims to:
reduce your risk of another heart attack through a combination of lifestyle changes, such as eating a healthy diet, and medications, such as statins (which help lower blood cholesterol levels)
gradually restore your physical fitness so you can resume normal activities (known as cardiac rehabilitation)
Most people can return to work after having a heart attack, but how quickly will depend on your health, the state of your heart and the type of work you do
Who is affected
Heart attacks are one of the most common reasons why a person requires emergency medical treatment.
Men are more likely to have a heart attack than women. The British Heart Foundation estimates that around 50,000 men and 32,000 women have a heart attack each year in England.
Most heart attacks occur in people aged over 45.
Complications
Complications of heart attacks can be serious and possibly life-threatening. These include:
arrhythmia – this is an abnormal heartbeat, where the heart begins beating faster and faster, then stops beating (cardiac arrest)
cardiogenic shock – where the heart's muscles are severely damaged and can no longer contract properly to supply enough blood to maintain many body functions
heart rupture – where the heart’s muscles, walls or valves split apart (rupture)
These complications can occur quickly after a heart attack and are a leading cause of death.
Many people will die suddenly from a complication of a heart attack before reaching hospital.
Outlook
The outlook for people who have had a heart attack can be highly variable, depending on:
their age – the older you are, the more likely you are to experience serious complications
the severity of the heart attack – specifically, how much of the heart's muscle has been damaged during the attack
how long it took before a person received treatment – the longer the delay, the worse the outlook tends to be
In general, around one third of people who have a heart attack die as a result. These deaths often occur before a person reaches hospital or, alternatively, within the first 28 days after the heart attack.
If a person survives for 28 days after having a heart attack, their outlook improves dramatically and most people will go on to live for many years.
Symptoms of a heart attack
Heart attack symptoms vary from one person to another. The most common signs are:
chest pain: tightness, heaviness or pain in your chest
pain in arms, neck, jaw, back or stomach: for some people, the pain or tightness is severe, while other people just feel uncomfortable
sweating
feeling light-headed
become short of breath
feeling nauseous or vomit
Treating heart attacks
A heart attack is a medical emergency. Dial 999 and ask for an ambulance if you think you or someone you know is having a heart attack.
If the casualty is not allergic to aspirin and it’s easily available, give them a tablet (ideally 300mg) to slowly chew and then swallow while waiting for the ambulance to arrive.
The aspirin will help to thin the blood and reduce the risk of a heart attack.
Treatment for a heart attack will depend on how serious it is. Two main treatments are:
using medication to dissolve blood clots
surgery to help restore blood to the heart
Read more about treating heart attacks.
Reducing your risk of a heart attack
There are five main steps you can take to reduce your risk of having a heart attack (or having another heart attack):
smokers should quit smoking
lose weight if you are overweight or obese
take regular exercise – adults should do at least 150 minutes (2 hours and 30 minutes) of moderate-intensity aerobic activity each week, unless advised otherwise by the doctor in charge of your care
eat a low-fat, high-fibre diet, including whole grains and plenty of fresh fruit and vegetables (at least five portions a day)
moderate your alcohol consumption – read more about the alcohol units