Heart Attack

Heart Attack (myocardial infarction or coronary thrombosis) is when part of the heart muscle dies because it has been starved of oxygen.

Usually, this happens when a blood clot forms in one of the coronary arteries (blood vessels to the heart muscle), which blocks the blood supply. Occasionally, a blockage is caused by a spasm (sudden narrowing) of a coronary artery.

Heart Attack generally causes severe and crushing pain in the middle of the chest. Often, the pain travels from the chest to the neck, jaw, ears, arms and wrists. The person may also be cold and clammy with a grey pallor (skin tone).

Approximately 300,000 people in the UK have a heart attack each year. It is a major cause of death affecting both men and women. Half of those who die, do so from cardiac arrest (the heart stopping completely) within 3 or 4 hours of the start of the attack.

Anyone suspected of having a heart attack should get medical attention immediately. The sooner the treatment, the more effective it will be and the greater the chance of survival.

Symptoms

If you suspect you or someone you know is having a heart attack, dial 999 immediately. Do not wait.

The common symptoms of a heart attack (MI) are:

• crushing central chest pain or mild chest discomfort,
• shortness of breath,
• clammy, sweaty, and grey complexion,
• dizziness,
• nausea and vomiting,
• restlessness,
• coughing,
• a  general feeling of being unwell,
• a frightening sense that one is about to die.

The pain often travels from the chest to the neck, jaw, ears, arms and wrists. Sometimes, it travels between the shoulder blades, back or to the abdomen.

The pain can last anything from 5 minutes to several hours.  Moving around, changing your position or resting doesn't stop or ease the pain. The pain may be constant or may come and go and feel like pressure, squeezing or fullness.

Some people do not  feel any pain during a heart attack.  This is known as a silent heart attack and tends to affect people with diabetes or those aged over 75 years.

There is evidence that up to 20% of mild heart attacks are not diagnosed. This means that some people, because of previous undiagnosed attacks, may be suffering progressive damage to the heart muscle

Heart attack causes

The factors that increase the risk of a heart attack include:

• men over 45 and women over 55,
• smoking,
• being overweight or obese,
• high blood pressure,
• high bloodcholesterol level,
• a diet high in saturated fats (animal fats),
• diabetes- the risk of heart attack in men with diabetes that started in adulthood is 3 times more likely and for women is 4 times more likely than in people without diabetes,
• a family history of heart disease,
• lack of regular exercise,
• severe sudden stress causing a fast heart rate, usually in someone who already has coronary artery disease. Such disease often shows no symptoms until a heart attack happens.

The risk of a heart attack is also increased if you have:

• angina, or
• have had a previous heart attack, heart bypass surgery or an angioplasty.
  Sometimes, angina can be mistaken for a heart attack as the signs are similar.  However, unlike a heart attack, angina will usually disappear within 15 - 20 minutes of resting and/or medication

Heart attack Diagnosis

On arrival in hospital, diagnosis will usually be confirmed using either an electrocardiograph (ECG) or cardiac enzyme tests.

ECG (electrocardiograph) - a tracing of the electrical activity of the heart that can detect any damage to the heart muscle or problems with the heart rhythm. It can show if a person has had a heart attack either recently or some time ago and if the heart is under a lot of strain. The test takes about 5 minutes and is not uncomfortable.

Cardiac enzyme tests - these look for certain heart muscle proteins that are only found in high levels immediately after a heart attack. The levels are measured from a series of blood samples taken over a few days.

Other background tests will be done to check for anaemia and kidney and liver function.

A chestX-ray may also be taken to look for enlargement (swelling) of the heart.

Heart attack Treatment

If you suspect either yourself or someone you know is having a heart attack, dial 999 immediately. Do not wait.

Most heart attacks can be successfully treated if immediate medical help is provided. The sooner the treatment, the more effective it will be and the greater the chance of survival.

Treatment during a heart attack Cardio-Pulmonary Resuscitation (CPR)

If the person is not breathing, coughing, moving or responding to stimulation (being touched or spoken to), immediate lifesaving treatment with cardio-pulmonary resuscitation (CPR) should be started. 

CPR consists of giving 30 chest compressions to massage the heart for every two mouth-to-mouth resuscitation breaths.

If the heart has stopped (cardiac arrest), the medical team at the scene or in hospital will try to restart the heart with a device called a defibrillator. This sends an electric shock across the chest to kick-start the heart. The heart rhythm may become temporarily irregular as it recovers, so this treatment is best given when the heart is being continuously monitored on an ECG in an ambulance or in hospital.

Aspirin - a one-off 300mg dose of aspirin is given straight away. This helps to prevent the blood clot in the coronary artery from getting bigger. Ideally it should be chewed or taken dispersed in water to ensure it gets into the bloodstream as quickly as possible.

Thrombolytics (clot-busters, e.g. alteplase, streptokinase) - dissolve the clot in the coronary artery allowing blood to flow back to the damaged heart muscle. 

They are given by injection as soon as possible, ideally within 1 hour of symptoms starting. The part of the heart muscle starved of blood does not die immediately. If blood flow is restored within a few hours, much of the heart muscle that would have been damaged will survive.

Morphine - an injection of morphine may be given to relieve the pain and help reduce anxiety.

Treatment following a heart attack

A number of medicines may be taken following a heart attack, often indefinitely, to improve survival and reduce the chance of a further attack.

Anti-platelets (e.g. aspirin, clopidogrel) reduce the 'stickiness' of platelets (tiny articles in blood that help it to clot). When a large number of platelets stick to an atheroma or plaque (fatty deposit) inside an artery they can form a thrombosis (clot). If this happens in a coronary artery, then it causes a heart attack.

Low dose aspirin is the preferred anti-platelet following a heart attack. A dose of 75mg or 150mg is given daily for 1 month after the attack. After this time, the usual dose is 75mg every day.

If you have a stomach or duodenal ulcer or asthma, you may not be able to take aspirin. Options then include taking an additional medicine to 'protect the stomach or to take a different anti-platelet medicine such as clopidogrel.

Beta-blockers (e.g. metoprolol, propranolol, timolol) have several effects that protect the heart after a heart attack. They make the heart beat slower and with less force, thus lessening the work it has to do. Also, they stabilise the hearts electrical activity.

Angiotensin-converting-enzyme inhibitors (ACE inhibitors) (e.g. lisinopril, perindopril, ramipril). These open up the blood vessels and lower blood pressure, thus easing the burden on the heart. They also appear to have a direct protective effect on the heart.

They are started at a low dose that is increased to a standard dose over 2-4 weeks. A blood test to check the kidneys are working properly is usually done before starting an ACE inhibitor, and about 7-10 days after the first dose. This is because ACE inhibitors can affect the kidneys of a small number of people who take them. A blood test to check the kidney function is done at least every year.

Statins (e.g. atorvastatin, fluvastatin, pravastatin, rosuvastatin, simvastatin).

These lower the bloodcholesterol level by preventing cholesterol from being made in the liver. Generally, the higher the bloodcholesterol level, the greater the risk of developing atheroma or plaques (fatty deposits) in the arteries. The aim is to reduce the total bloodcholesterol level to below 4 mmol/l or by 25% of the original blood level whichever gives the greatest reduction.

Surgery In some cases, surgery may be required such as coronary angioplasty or coronary artery bypass graft (CABG).

Angioplasty is surgery to open up a coronary artery.  It is usually carried out after recovery from the heart attack but in some specialized units, it may be performed as an emergency treatment for people having a very serious heart attack.

A tiny wire with a sausage-shaped balloon at the end is put into a large artery in the groin or arm. It is then passed through the blood vessels up to the heart and into the narrowed section of a coronary artery using X-ray guidance. The balloon is then blown up inside the narrowed part of the artery to open it wide again. A stent (a flexible metal mesh) is usually inserted into the artery to help keep it open afterwards.

Coronary Artery Bypass Graft (CABG) is surgery to bypass an artery blockage with healthy blood vessel segments (grafts) taken from other parts of the body.

Segments of vein from the legs or chest are used to create a new channel through which the blood can be directed past the blocked part of the artery. More blood can then get past into the heart muscle. Not everyone with angina is suitable for this surgery as it depends on where the narrowed arteries are.

Recovery and rehabilitation
In a straightforward recovery, it is normal to be home within a week or less. After a heart attack, follow-up care is important to reduce the risk of you having another attack.

Exercise-based cardiac rehabilitation programmes reduce the risk of future problems and help you return to a normal life. These usually start 6 weeks after your heart attack and include advice on diet and any lifestyle changes that are needed e.g. quitting smoking.

Work can be restarted 4-12 weeks after the heart attack, depending on how physical your job is.

Driving can restart after one month, but the DVLA and your insurance company must be informed of the heart attack as soon as possible.

Heart attack Complications

The complications of a heart attack are divided into those that happen immediately, and those that appear later on.

Immediate complications include:

• arrhytmias these are irregular, uneven heart rhythms (very fast or slow rate). If necessary, these can be corrected by passing an electric current through the heart (cardioversion). However, in most cases, the heart rate will return to normal, either naturally or with the help of medication,
• cardiogenic shock - dangerous drops in blood pressure,
• hypoxaemia - low levels of oxygen in the blood,
• pulmonary oedema - fluid build-up in and around the lungs,
• deep vein thrombosis - blood clots forming in the deep veins of the legs or pelvis,
• myocardial rupture - rupture of the heart wall where it has been damaged by the heart attack,
• ventricular aneurysm a bulge in the wall of the ventricle (heart chamber), and
• an increased risk of another heart attack.

Later complications include:

• aneurysm (blow out) caused by build up of scar tissue on the damaged heart wall. An aneurysm can result in abnormal heart rhythms, blood clots and low blood pressure,
• pericarditis - Inflammation of the lining of the heart. This can happen days or months later,
• angina (chest pain) caused by shortage of oxygen to the heart,
• congestive heart failure - weak pumping of the heart, causing breathlessness and oedema (build-up of fluid in the ankles and legs),
• depression, loss of confidence, loss of sex drive and fear of having sex (very common), and
• increased risk of heart attack in the future

Heart attack Prevention

The five main risk factors that can lead to a heart attack are:

• smoking,
• not getting enough exercise (physical inactivity),
• high blood pressure,
• being overweight or obese,
• high bloodcholesterol levels,

Drinking too much alcohol and having too much salt in your diet can also increase the risk of coronary heart disease, which can lead to a heart attack.

To reduce the risk of having a heart attack, you should make changes to your lifestyle:

Give up smoking — Smoking is a major contributor to many serious diseases, such as heart disease and lung cancer and is the biggest cause of death and illness in the UK.

If you have had a heart attack and continue to smoke, there is an increased risk of having another attack within a year. The NHS Smoking helpline 0800 169 0 169 can offer information and support to people who want to give up smoking.

Take regular exercise — Take regular aerobic exercise (for example, a brisk, 20 minute walk or swimming, three times per week). This reduces blood pressure, weight and bloodcholesterol level, and increases the fitness of the heart muscle. It can also reduce the risk of developing diabetes or having a stroke. Physical activity will help reduce the risk of another heart attack by 25%.

Reduce your cholesterol — Reduce the animal fat content of your diet.
A Mediterranean diet using unrefined olive oil and coloured vegetables such as tomatoes and peppers is now thought to help reduce the risk of heart disease.

Foods high in cholesterol and fat increase cholesterol levels in the body. Cut down on fatty food such as chips, red meat, butter, cheese, pastries, cakes and biscuits and try baking, steaming, poaching and grilling your food instead of frying or roasting it.

To stay healthy, make sure that no more than a third of your daily food intake contains fat. This is about 75g of fat per day for women and roughly 100g for men. People who eat 5 portions of fruit and vegetables a day are less likely to have heart disease.

Lose weight — There are many benefits to losing weight. If you get to the ideal weight for your height this will help to lower your cholesterol levels and blood pressure. You will dramatically lower your risk of heart disease, as well as increase your life expectancy.

The most successful weight loss programmes include 30 minutes of daily exercise, eating smaller portions, and only having healthy snacks between meals. A gradual weight loss of around 1-2lb (0.45-0.9kg) per week is usually recommended.

Reduce your blood pressure — You can reduce your blood pressure by eating a healthy diet with less salt, and lose weight if necessary. Stop smoking, exercise regularly and reduce your alcohol and caffeine intake. If you find yourself getting stressed, this will increase your blood pressure so try to calm down by taking slow, deep breaths. 

Make sure you have regular blood pressure checks, especially if there is a family history of hypertension (high blood pressure). This way, medicines to treat hypertension can be started before any complications arise.

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