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heart attack

Heart attack

This factsheet is for people who have had a heart attack (myocardial infarction or coronary thrombosis), or who would like information about it.

A heart attack happens when a coronary artery (a blood vessel that supplies the heart with blood) carrying oxygen-rich blood to heart muscle is blocked. If the blood supply is cut off, part of the heart muscle may be starved of oxygen and can become permanently damaged.

About heart attacks
Heart disease is the most common cause of death in the UK. In 2006, about 113,000 people had a heart attack for the first time. Heart attacks become more common with increasing age and are generally more common in men than women.

You can have a heart attack at any time of the day or night, when you’re either resting or being active. Occasionally, a heart attack can be brought on by doing energetic activity that you aren’t used to, or by intense physical or emotional stress.

You’re more likely to have a heart attack if you:

have a family history of heart disease
lead an inactive lifestyle (doing less than 30 minutes physical activity per day, on most days)
have diabetes
are overweight or obese
have high blood pressure
have high blood cholesterol

A coronary artery affected by arthrosclerosis

Symptoms of a heart attack
If you have a heart attack, you will most likely feel severe pain in the centre of your chest. This central chest pain is often described as heaviness, squeezing or crushing, and may come on suddenly causing you to collapse. The pain sometimes feels like severe indigestion. Other symptoms include:

pain spreading to the arms, neck, jaw, back or stomach
feeling sweaty and breathless
feeling sick or vomiting
The symptoms of a heart attack can come on suddenly, but sometimes the pain develops more slowly. If you already have angina (narrowing of your coronary arteries without complete blockage), you will find that the pain of a heart attack won’t completely respond to your usual medicine (eg glyceryl trinitrate, or GTN). Heart-attack pain continues for longer than angina and can last for hours.

Sometimes you may not have any symptoms at all, especially if you’re elderly or have diabetes.

During a heart attack, life-threatening heart rhythms may develop, which is why a heart attack is a medical emergency.

If you suspect you’re having a heart attack, call for emergency help immediately.

Complications of a heart attack
Once the initial discomfort of a heart attack has settled (usually within 24 to 48 hours) there are often no complications afterwards. However, in the first few days after surviving a heart attack, your heart may beat in irregular, unusually fast or slow rhythms – these are known as arrhythmias.

After having a heart attack, your heart may not be able to pump blood around your body as efficiently as before. This is called heart failure. The larger the area of your heart muscle affected by a heart attack, the more likely you are to have heart failure.

Other, rarer complications include blood clots in the lungs, stroke, inflammation of the membrane covering the heart (pericarditis), or a bulging weakness in the heart muscle (aneurysm).

Causes of a heart attack
The underlying cause of most heart attacks is atherosclerosis – this is where the coronary arteries become narrowed over many years by fatty deposits (plaques). These plaques are thought to split open (rupture), releasing substances that cause the blood flowing in the coronary artery to clot. The plaque and blood clot (thrombus) can together completely block the coronary artery, stopping blood flow to your heart and causing a heart attack.

Diagnosis of a heart attack
When you get to hospital, a doctor and nurse will assess your symptoms and medical history. You will have:

a physical examination – this involves measuring your blood pressure and monitoring your heart rate
an ECG (electrocardiogram) – this checks the electrical activity of your heart and helps to diagnose any partial or complete blockages of the coronary arteries
blood tests to check for any damage to your heart muscle
Treatment of a heart attack
Emergency medical treatment is vital – getting to a hospital quickly and receiving specialist care greatly improves your chances of survival. If you can swallow, chew a single aspirin tablet, unless you know that you’re allergic to it. Aspirin thins the blood and can help to prevent the clot that is blocking the coronary artery from spreading.

In response to an emergency call for a suspected heart attack, the ambulance service will send a paramedic as quickly as possible. His/her job is to stabilise you and provide transport to a hospital quickly and safely for further treatment. A paramedic may have to provide oxygen and pain-relieving medicine. Some paramedics, especially in rural areas, are also trained to give patients clot-dissolving drugs (also known as “clot-busters” or thrombolytics) before reaching the hospital.

During a heart attack, there may be disturbances in your heart rhythm. The most serious form of this is called ventricular fibrillation. This is when the electrical activity of the heart becomes so erratic that it stops pumping and quivers or ‘fibrillates’ instead (known as cardiac arrest). If this happens, the paramedic may need to use a defibrillator, which gives a large electric shock through the wall of your chest and can restore a regular heartbeat (resuscitation).

Hospital treatment
At hospital, you will usually be given an injection of a thrombolytic to dissolve the clot in your coronary artery. This increases your risk of bleeding so it won’t be given if it could cause problems, for example if you have recently had surgery. Your chances of making a full recovery from your heart attack are much better if the clot is dissolved.

In some hospitals you may be taken on admission for immediate angioplasty (see Surgery), as this treatment is increasingly used.

Other medicines, such as beta-blockers (eg atenolol) or GTN, may be given to increase the blood supply to your heart by widening your blood vessels.

If your arteries are narrowed, you can sometimes be treated with angioplasty or a coronary artery bypass graft (CABG).

Angioplasty involves widening your artery by inflating a balloon in the narrowed coronary artery. A wire mesh tube called a stent is sometimes inserted to hold it open.

CABG surgery involves redirecting your blood around the affected artery. This is done either using a replacement section of a blood vessel (a graft), which is usually taken from a leg vein or by diverting another artery in the chest wall (the internal mammary artery).

After treatment of a heart attack
For the best possible recovery after a heart attack, you should start a cardiac rehabilitation programme. These programmes can vary but usually include an exercise regime devised by a physiotherapist, along with advice on relaxation, lifestyle modification and treatment choices. They may also give you a chance to meet others who are also recovering from heart attacks. A cardiac rehabilitation programme should ideally begin when you’re admitted to hospital and continue after you leave. In many hospitals a member of the cardiac rehabilitation team will visit you to discuss your condition. He/she can also provide you with recovery advice for getting back to your usual activities.

After a heart attack, you may need to take medicines regularly for a long time. Your doctor may prescribe a low daily dose of aspirin (around 75mg). Other medicines you may be prescribed include statins (eg simvastatin), ACE inhibitors (eg ramipril), beta-blockers (eg bisoprolol) and thienopyridines (eg clopidogrel). Your risk of further heart attacks can be reduced by using these medicines.

Always ask your doctor for advice and read the patient information leaflet that comes with your medicine.

Prevention of heart attack
To keep your heart healthy and reduce the risk of heart problems, you should:

stop smoking
lose excess weight
take regular exercise
eat a healthy balanced diet, low in fat and high in fibre
Even if you have previously had a heart attack, these measures can still reduce your chances of having another one.

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