A heart attack is the death of a segment of heart muscle caused by a loss of blood supply. The blood is usually cut off when an artery supplying the heart muscle is blocked by a blood clot.
If some of the heart muscle dies, a person experiences chest pain and electrical instability of the heart muscle tissue.

This MNT Knowledge Center will cover information about how and why heart attacks occur, how they are treated, and how to prevent them.

Fast facts on heart attacks:
During a heart attack, the heart muscle loses blood supply and is damaged.
Chest discomfort and pain are common symptoms.
The risk of a heart attack increases when a man is over 45 and a woman is over 55.
Smoking and obesity are big factors, particularly in the at-risk age range.
Symptoms
Heart attacks are a serious form of heart disease, with many different causes.
Heart attacks are a serious form of heart disease, with many different causes.
There are clear symptoms of a heart attack that require immediate medical attention.

A feeling of pressure, tightness, pain, squeezing, or aching in the chest or arms that spreads to the neck, jaw, or back can be a sign that a person is having a heart attack.

The following are other possible signs and symptoms of a heart attack occurring:

coughing
nausea
vomiting
crushing chest pain
dizziness
shortness of breath called dyspnea
face seeming gray in color
a feeling of terror that life is ending
feeling awful, generally
restlessness
feeling clammy and sweaty
shortness of breath
Changing position does not alleviate the pain of a heart attack. The pain a person feels is normally constant, although it may sometimes come and go.

Warning signs
As heart attacks can be fatal, it is vital to recognize the warning signs that an attack is occurring.

While the symptoms listed above are all linked to heart attacks, there are four warning signs listed by the American Heart Association (AHA) as being crucial signs of an attack. These include:

discomfort, pressure, squeezing, or fullness in the chest that lasts several minutes or resolves then returns
pain or discomfort in the arms, neck, back, stomach, or jaw
sudden shortness of breath
Other signs can include a cold sweat, a sick or nauseous feeling, or being lightheaded.

When a person has these symptoms, the emergency services should be called immediately.

Complications
There are two types of complications that can happen following heart attack. The first occurs pretty much straightaway and the second happens later on.

Immediate complications
Arrhythmias: the heart beats irregularly, either too fast or too slowly.
Cardiogenic shock: a person's blood pressure drops suddenly and the heart cannot supply enough blood for the body to work adequately.
Hypoxemia: levels of oxygen in the blood become too low.
Pulmonary edema: fluid accumulates in and around the lungs.
DVT or deep vein thrombosis: the deep veins of the legs and pelvis develop blood clots that either block or interrupt the flow of blood in the vein.
Myocardial rupture: the heart attack damages the wall of the heart, meaning an increased risk of a heart wall rupture.
Ventricular aneurysm: a heart chamber, known as a ventricle, forms a bulge.
Complications that can occur later
Aneurysm: scar tissue builds up on the damaged heart wall, leading to blood clots, low blood pressure, and abnormal heart rhythms.
Angina: not enough oxygen reaches the heart, causing chest pain.
Congestive heart failure: the heart can only beat very weakly, leaving a person feeling exhausted and breathless.
Edema: fluid accumulates in the ankles and legs, causing them to swell.
Loss of erectile function: erectile dysfunction is generally caused by a vascular problem. However, it can also be the result of depression.
Loss of libido: a loss of sexual drive can happen, especially in the case of men.
Pericarditis: the lining of the heart becomes inflamed, causing serious chest pain.
It is important that a doctor monitors a person for several months after they have had a heart attack to check for any of these complications that may occur.

Treatment
The quicker someone is treated when having a heart attack, the greater the chances of success. These days, most heart attacks can be dealt with effectively.

However, it is crucial to remember that a person's survival depends largely on how quickly they reach the hospital.

Treatments during a heart attack
Sometimes, a person who is having a heart attack will stop breathing. In this case, cardio-pulmonary resuscitation, or CPR, should be started immediately. This process involves:

manual chest compressions
a defibrillator
Treatments following a heart attack
One of the main treatments during a heart attack is use of defibrillator panels.
Defibrillator panels can be effective during a heart attack.
Most people will need several kinds of medications or treatments after a heart attack. The aim of these measures is to prevent future heart attacks occurring. They may include:

aspirin and other antiplatelets
beta blockers
ACE (angiotensin converting enzyme) inhibitors
statins
angioplasty
CABG or coronary artery bypass graft
Definition
A heart attack is a medical emergency in which the supply of blood to the heart becomes blocked, often as the result of a blood clot.

Other terms used for a heart attack include myocardial infarction, cardiac infarction, and coronary thrombosis. An infarction is when the blood supply to an area is cut off, and the tissue in that area dies.

A heart attack is often confused for a cardiac arrest. While they are both medical emergencies, a heart attack is the blockage of an artery leading to the heart, and a cardiac arrest involves the heart stopping the pumping of blood around the body. A heart attack can lead to cardiac arrest.

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Prevention
The best way of preventing a heart attack is to have a healthy lifestyle. Measures for healthy living include the following:

not smoking
eating a balanced, healthful diet
getting plenty of exercise
getting plenty of good quality sleep
keeping diabetes under control
keeping alcohol intake down
maintaining blood cholesterol at optimum levels
keeping blood pressure at a safe level
maintaining a healthy body weight
avoiding stress where possible
learning how to manage stress
It may be helpful for people to learn more about the warning signs of a heart attack, as well.

Diagnosis
Any doctor, nurse, or healthcare professional will send someone straight to hospital if they suspect they may be having a heart attack. Once there, several tests may be done, including:

ECG or electrocardiograph
cardiac enzyme tests
chest X-ray
Recovery
Recovering from a heart attack can be a gradual process. It depends on the severity of the heart attack and other factors, such as a person's age.

A person's recovery may involve:

Resuming physical activity: it is vital that a recovering heart attack patient stays active. However, a specialist should design any exercise program for them.
Returning to work: the appropriate time for someone to go back to work depends on various factors, including the severity of the heart attack and the type of job they do. It is vital not to rush back to work.
A period of depression: many people who have had a heart attack experience depression not long afterward. Those who feel depressed or anxious should tell their doctors.
Driving again: experts advise that a person refrains from driving for at least 4 weeks after a heart attack.
Erectile dysfunction: approximately one-third of men have problems getting or sustaining an erection after a heart attack.
It is important that men with erectile dysfunction talk to their doctors, as medication can restore function in most cases.

Experts say that sexual activity does not raise a person's risk of having another heart attack.

Causes
The following factors are associated with increased risk of a heart attack:

Age: Heart attacks are more likely when a man is over 45, and when a woman is over 55.
Angina: This causes chest pain due to lack of oxygen or blood supply to the heart.
High cholesterol levels: These can increase the chance of blood clots in the arteries.
Diabetes: This can increase heart attack risk.
Diet: For example, consuming large quantities of saturated fats can increase the likelihood of a heart attack.
Genetics: A person can inherit a higher risk of heart attack.
Heart surgery: This can lead to a heart attack later on.
Hypertension: High blood pressure can put unnecessary strain on the heart.
Obesity: Being significantly overweight can put pressure on the heart.
Previous heart attack.
Smoking: Smokers are at much higher risk than non-smokers.
HIV: People who are HIV-positive have a 50 percent higher risk.
Work stress: Those who are shift workers or have stressful jobs can face a higher heart attack risk.
Physical inactivity is a factor in heart attack risk, and the more active people are, the lower their risk of having a heart attack.