Patient Information > Heart Attack (myocardial infarction)

Heart Attack (myocardial infarction)

What is a heart attack?
Symptoms of a heart attack
Causes
Long term effects and complications
Treatment

What is a heart attack?

Your heart is a muscular pump which pumps oxygen-rich blood around your body. Your heart needs its own energy supply to do this – the coronary arteries. There are three main coronary arteries which supply the heart with its own supply of oxygen-rich blood.

A heart attack (myocardial infarction) happens when the supply of oxygen-rich blood to part of the heart is restricted, and an area of heart muscle dies. This usually happens when one of the coronary arteries becomes narrowed by fatty deposits within its walls or blocked by a blood clot. When this happens, the part of the heart it supplies dies. How serious a heart attack is depends on the amount of heart muscle that is affected.

Symptoms of a heart attack

A heart attack often happens very suddenly, without much warning. The most common signs are:

a gripping or pressure-like pain that begins behind the breastbone, often spreading to the neck, jaw and down into the arms (it is not brought on by exertion or relieved by rest);
sweating;
weakness;
loss of consciousness; and
a weak pulse or one that is difficult to find.

Causes

A heart attack is a type of coronary heart disease which happens when the blood supply to the heart is restricted. This restricted blood flow is caused by ‘atherosclerosis’, a build-up of fatty deposits in the lining of the arteries which narrows the arteries and reduces blood flow.

Smoking, lack of exercise, a high-fat and high-salt diet, being overweight, high blood pressure, high cholesterol and diabetes are the main factors which contribute to coronary heart disease.

Long term effects and complications

Within a few hours of having a heart attack, your damaged heart muscle will begin to heal and gradually strengthen your heart. This is a gradual process, and over the next few weeks scar tissue will form to strengthen your heart.

Although most people’s hearts will be working just as well as they were before the heart attack, some people may experience angina (pain or tightness in the chest on exercise) or problems with breathlessness, tiredness or swollen ankles, which tends to happen if the heart is not pumping blood as effectively as before (heart failure). If you notice these symptoms, tell your doctor.

If you have had a heart attack, you are already at risk of it happening again. You can greatly reduce your risk of this happening again by taking all your medicines exactly as your doctor prescribes and making sure your lifestyle is as healthy as possible.

• If you smoke, stop now.
• Eat at least five (but ideally seven to 10) portions of fresh fruit and vegetables a day.
• Cut down on salt, fats and sugars in your diet.
• Take some moderate exercise every day (walking, swimming and cycling are ideal).
• Lose weight if you need to.
• If you drink alcohol, do not drink more than two to three units each day for men or one to two units each day for women. Don’t binge drink and make sure you have alcohol-free days in the week.
• Take your medication as prescribed. If you are not sure, ask your doctor or pharmacist.

Treatment

A heart attack is treated as an emergency because of how serious the pain is and the risk to your life if your heart stops beating altogether (cardiac arrest).Immediately after your heart attack, you will be given oxygen through a face mask and medication to help the pain, together with medicines to help thin your blood. Once the immediate situation is under control you may be given:

• medicines to help prevent another heart attack (aspirin, anticoagulants, ACE inhibitors, beta-blockers or anti-arrhythmic drugs);
• medicines to help relieve breathlessness and heart failure (diuretics, ACE inhibitors or beta-blockers); and
• medicines to treat angina (nitrates, calcium antagonists or beta-blockers). If tests show that your coronary arteries are very badly blocked, your doctors may consider surgery to widen the artery (angioplasty) or re-route the blood flow (bypass graft).