A heart attack is a serious medical emergency in which the supply of blood to the heart is suddenly blocked, usually by a blood clot. The lack of blood to the heart can seriously damage the heart muscles. If left untreated, the muscles will begin to die. The medical term for a heart attack is myocardial infarction.

Most heart attacks occur in people with coronary heart disease, which is caused by atherosclerosis. Atherosclerosis is a serious condition where the arteries become narrowed and hardened by the build-up of clumps of cholesterol, called plaques.

The two arteries that supply the heart are called the coronary arteries. People with hardened and narrowed coronary arteries are said to have coronary heart disease (CHD).

Risk factors for CHD include:

• Smoking
• High-fat diet
• Diabetes
• Being overweight or obese

How common are heart attacks?

Heart attacks are very common and are one of the leading causes of death in England. Each year in Ireland, an estimated 6,000 people have a heart attack. Many heart attacks that lead to death are preventable. This is because most of the risk factors that are listed above can also be prevented.

Most heart attacks occur in people who are over 45 years of age. Men are two to three times more likely to have a heart attack than women.

Over the last decade, death rates from heart attacks have fallen by around 40%. This may be related to an associated decrease in the number of people smoking cigarettes. However, the number of deaths is still higher than in many other western European countries. It is thought that this is because Ireland has higher rates of obesity, diabetes and physical inactivity (people not exercising enough) than in other countries.

Treatment options for a heart attack can involve using medication to dissolve any blood clots and surgery to widen the coronary artery.

Outlook

The outlook for people who have a heart attack is highly variable and is dependent on two important factors:

• How quickly they receive treatment after the onset of the heart attack (ideally treatment should begin within 90 minutes of the onset of symptoms)
• How well they respond to treatment within the first 28 days after the heart attack
• Currently, just over half the people who have a heart attack die during the first 28 days after the heart attack. Of these deaths, 75% occur in the first 24 hours and 30% of them occur before the person is admitted to hospital.
• 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.
• In those who survive a heart attack, a combination of lifestyle changes and medication is usually recommended to reduce the risk of having another heart attack.

Symptoms

Dial 999 immediately if you suspect that you or someone you know is having a heart attack.

The symptoms of a heart attack include:

• Chest pain: the pain is usually located in the centre of your chest and can feel like a sensation of pressure, tightness or squeezing
• Pain in other parts of the body: it can feel as if the pain is travelling from your chest to your arms (usually the left arm is affected but it can affect both arms), jaw, neck, back and abdomen
• Shortness of breath
• Nausea
• An overwhelming sense of anxiety (similar to having a panic attack)
• Feeling light headed
• Coughing
• Vomiting
• Wheezing

The level of pain can vary significantly from person to person. For many people, the pain is severe and it has been described as feeling like 'an elephant was sitting on my chest'. However, this is not always the case. For others, the pain can be minor and is similar to that experienced during indigestion. Also, some women and older people do not experience any chest pain at all.

It is not the level of chest pain that is important in determining whether you are having a heart attack. Instead, it is the overall pattern of symptoms that is important.

The misconception that a heart attack always causes severe chest pain has led to many people dying needlessly. One American study found that a third of people who had a heart attack did not call an ambulance.

Do not worry if you have any doubts about whether your symptoms indicate that you are having a heart attack. Assume that you are having a heart attack and dial 999 to ask for an ambulance immediately.

Paramedics would much rather be called out to find out that an honest mistake has been made than be called out when it is too late to save a person's life.

Waiting for the ambulance

If you know that you are not allergic to aspirin and aspirin is easily available, chew (do not swallow) an adult size tablet, 300mg, while you are waiting for the ambulance to arrive. The aspirin will help to thin your blood and restore the blood supply to your heart.

Causes

Like all the other tissues and organs in the body, the heart needs a constant supply of oxygen-rich blood. If the blood supply to the heart is suddenly interrupted, the heart muscles may be damaged and begin to die.

If this is not treated, the heart muscles will experience irreversible damage. If a large portion of the heart is damaged in this way, the heart will stop beating (cardiac arrest), resulting in death.

Coronary heart disease (CHD)

Coronary heart disease (CHD) is the leading cause of heart attacks. CHD is a condition in which the coronary arteries (the major blood vessels that supply the heart with blood) get clogged up with deposits of cholesterol. These deposits are called plaques.

During a heart attack, one of the plaques ruptures (bursts), causing a blood clot to develop at the site of the rupture. The blood clot may then block the supply of blood running through the coronary arteries to the heart, triggering a heart attack.

Risk factors

The risk factors for CHD, many of which are interrelated (related to each other), are outlined below.

Smoking

• The toxins that are contained in cigarettes narrow and damage the coronary arteries. This makes people who smoke more vulnerable to CHD. Compared with non-smokers, people who smoke 20 or more cigarettes a day are 60-90% more likely to develop CHD and have a heart attack.
• Even small amounts of tobacco can be harmful. If you smoke only one cigarette a day, you are still 30% more likely to develop CHD than a non-smoker.

Diet

If you eat a diet that is high in saturated fat, your blood cholesterol levels will rise. This leads to an increase in your risk of CHD and heart attacks.

Some foods, such as oily fish, can help lower your cholesterol level. See Preventing a heart attack for more information about how diet can influence your heart attack risk.

High blood pressure

Having poorly controlled high blood pressure (hypertension) can weaken the coronary arteries, making them more vulnerable to CHD. The higher your blood pressure, the greater your risk of CHD and heart attacks.

Diabetes

The increased levels of blood glucose associated with type 1 diabetes and type 2 diabetes can damage the coronary arteries, making them more vulnerable to CHD.

It is estimated that people with diabetes are 2-5 times more likely to develop CHD than the general population.

Being overweight or obese

Being overweight or obese does not directly increase your risk of CHD and heart attacks, but leads to related risk factors that do. In particular, people who are overweight or obese:

• Have an increased risk of developing high blood pressure
• Tend to have higher levels of cholesterol as a result of eating a high-fat diet
• Have an increased risk of developing type 2 diabetes

Lack of exercise

Lack of exercise is not directly related to an increased risk of CHD and heart attacks. However, it is linked to an increased risk of being overweight or obese and having high blood pressure (hypertension).

Alcohol

Excessive consumption of alcohol can cause high blood pressure (hypertension) and increased blood cholesterol levels, increasing the risk of developing CHD. Most heavy drinkers also tend to have unhealthy lifestyles, such as smoking, eating a high-fat diet and not exercising enough.

Age and sex

The older you get, the more likely you are to develop some degree of CHD.

Men are 2-3 times more likely to have a heart attack than women. In the past, the increased risk could be explained (to a certain extent) by the fact that more men smoked cigarettes. However, today the number of men and women who smoke is roughly the same, but men are still more at risk of having a heart attack than women.

A number of theories have been suggested to explain this increased risk, such as:

• Higher rates of excessive alcohol consumption in men
• More men are overweight than women (although obesity levels are roughly the same for both sexes)
• Men may be less effective at coping with stress than women, and increased stress levels may affect their physical wellbeing

Family history

If you have a first-degree relative (a parent, brother or sister) with a history of heart disease, such as angina, heart attack or stroke, you are twice as likely to develop similar problems compared to the general population.

Ethnicity

Rates of high blood pressure and diabetes are higher in people of African and African-Caribbean descent, which means that they also have an increased risk of CHD and heart attacks.

People of South Asian descent (those of Indian, Bangladeshi, Pakistani and Sri Lankan origin) are five times more likely to develop diabetes than the general population. Again, this increases their risk of CHD and heart attacks.

Less common causes

Some less common causes of a heart attack are described below.

Drug misuse

Stimulants, such as cocaine, amphetamines (speed), crack and methamphetamines (crystal meth), can sometimes suddenly cause the coronary arteries to narrow, restricting the blood supply and triggering a heart attack. Heart attacks due to the use of cocaine are one of the most common causes of sudden death in young people.

Lack of oxygen in the blood (hypoxia)

If the levels of oxygen in the blood decrease due to carbon monoxide poisoning or a loss of normal lung function, the heart will receive un-oxygenated blood. This will result in the heart muscles being damaged, triggering a heart attack.

Aneurysm

An aneurysm is a weakness in a blood vessel wall. If the blood vessel wall becomes weakened beyond a certain point, it will no longer be able to withstand the pressure of blood running through it and it will rupture (burst).

Sometimes, an aneurysm can develop inside the coronary arteries, although this is much less common than other types of aneurysm. If a coronary artery aneurysm ruptures, the blood supply to the heart will stop, triggering a heart attack.

Diagnosing

If a heart attack is suspected, you should be admitted to hospital immediately. You will usually be admitted to an intensive care unit (ICU) so that the diagnosis can be confirmed and treatment can begin.

Electrocardiograph (ECG)

An electrocardiograph (ECG) is an important test in cases of suspected heart attacks. An ECG should be carried out within 10 minutes of being admitted to hospital.

An electrocardiograph (ECG) measures the electrical activity of your heart. Every time your heart beats, it produces tiny electrical signals. An ECG machine records these signals onto paper, allowing your doctor to see how well your heart is functioning.

An ECG is painless and takes about five minutes to perform. During the test, electrodes (flat metal discs) are attached to your arms, legs and chest. Wires from the electrodes are connected to the ECG machine, which records the electrical impulses.

There are two reasons why an ECG is so important:

• It helps confirm the diagnosis of a heart attack
• It helps determine what type of heart attack you have had, which will help determine the most effective treatment for you

Types of heart attack

Heart attacks can be classified by a measurement that is known as the ST segment. The ST segment is an electrical measurement that is recorded by an ECG. It corresponds to the level of damage that has been inflicted on the heart. The higher the ST segment, the greater the amount of damage that is likely to have occurred.

There are three main types of heart attack:

• ST segment elevation myocardial infarction (STEMI)
• Non-ST segment elevation myocardial infarction (NSTEMI)
• Unstable angina

ST segment elevation myocardial infarction (STEMI)

ST segment elevation myocardial infarction (STEMI) is the most serious type of heart attack. In this type of heart attack, a prolonged interruption to the blood supply, resulting from a total blockage of the coronary artery, causes extensive damage to a large area of the heart. A STEMI is what most people think of when they hear the term heart attack.

Non-ST segment elevation myocardial infarction (NSTEMI)

Non-ST segment elevation myocardial infarction (NSTEMI) is less serious than a STEMI. This is because the supply of blood to the heart is only partially blocked, rather than completely blocked. As a result, a smaller section of the heart is damaged. However, NSTEMI is still regarded as a serious medical emergency.

Unstable angina

Unstable angina is the least serious type of heart attack although, like NSTEMI, it is still regarded as a medical emergency. In unstable angina, the blood supply to the heart is still seriously restricted, but the extent of the damage is much less severe than in cases of STEMI and NSTEMI.

Other tests

A number of other tests can be used to assess the state of your heart and check for related complications. However, because heart attacks are medical emergencies, some of these tests are usually only carried out once your initial treatment has begun and your condition has stabilised.

Blood tests

The damage to your heart that results from a heart attack causes certain enzymes to slowly leak into your blood. Enzymes are special proteins that help regulate the chemical reactions that take place in your body.

If you have had a suspected heart attack, a sample of your blood will be taken so that it can be tested for these heart enzymes. Your enzyme levels will be measured through a series of blood samples that will be taken over the course of a few days. This will allow the level of damage to your heart to be assessed, and it will also help determine how well you are responding to treatment.

Chest X-ray

A chest X-ray can be useful if the diagnosis of a heart attack is uncertain and there are other possible causes of your symptoms, such as a pocket of air trapped between the layers of your lungs (pneumothorax).

A chest X-ray can also be used to check whether any complications have arisen from the heart attack, such as a build-up of fluid inside your lungs (pulmonary oedema).

Echocardiogram

An echocardiogram is similar to an ultrasound scan in that it uses sound waves to build up a picture of the inside of your heart. This can be useful to identify exactly which areas of the heart have been damaged and how this damage has affected your heart's function.

Coronary angiography

Coronary angiography can help determine whether a blockage or narrowing has occurred in the coronary arteries and, if so, to locate the exact location of the blockage or narrowing.

The test involves inserting a thin tube, known as a catheter, into one of the blood vessels in your groin or arm. The catheter is guided into your coronary arteries using X-rays.

A special fluid, known as a contrast agent, is pumped through the catheter. This fluid shows up on X-rays. Studying how it flows around and through your heart can help locate the site of any blockage or narrowing.

A coronary angiogram is often performed just before surgery because the results can help guide the efforts of the surgeon.

Treating

Your treatment plan will depend on the type of heart attack you have had. For example, if you have had an ST segment elevation myocardial infarction (STEMI), there are two treatment options:

• A combination of medication to dissolve the blood clot and restore the flow of blood to the heart (this is known as thrombolysis)
• Surgery to widen the coronary artery, which is usually done using a technique called coronary angioplasty
• If you have had a non-ST segment elevation myocardial infarction (NSTEMI) or unstable angina, thrombolysis is usually recommended as the first treatment option.
• If your symptoms do not improve, a coronary angioplasty can be carried out. These treatment options are discussed in more detail below.

STEMI

As STEMI is the most serious type of heart attack, it is important that it is treated quickly. Therefore, once the diagnosis has been confirmed, an immediate decision has to be made as to whether you are treated with surgery or thrombolysis.

Research has shown that surgery is the most effective treatment for STEMIs. However, a coronary angioplasty is a very complex type of surgery that requires specialist staff and equipment, and not all hospitals have the facilities needed to perform the surgery. However, by 2012, the Department of Health hopes to extend angioplasty services across England.

In most cases, surgery would only be the preferred option if it can be carried out within 90 minutes of you being admitted to hospital.

Thrombolysis is usually the preferred option if the facilities for surgery are not available and it would take longer than 90 minutes to transfer you to a hospital where surgery is available. This is because it may be too risky to delay treatment any longer.

Coronary angioplasty

During coronary angioplasty, a tiny wire with a sausage-shaped balloon at the end is put into a large artery in your groin or arm. The wire is passed through your blood vessels and up to your heart, using X-rays to guide it, before being moved into the narrowed section of your coronary artery.

Once in position, the balloon is inflated inside the narrowed part of the artery to open it wide. A stent (flexible metal mesh) is usually inserted into the artery to help keep it open afterwards.

CABG

Sometimes, a coronary angioplasty may not be technically possible if the anatomy of your arteries is different from normal. This may be the case if there are too many narrow sections in your arteries or if there are lots of branches coming off your arteries that are also blocked.

In such circumstances, an alternative surgical procedure, known as a coronary artery bypass graft (CABG), may be considered. CABG involves taking a blood vessel from another part of your body, usually your chest or leg, to use as a graft.

The graft replaces any hardened or narrowed arteries in the heart. A surgeon will attach the new blood vessel to the coronary artery above and below the narrowed area or blockage.

Thrombolysis

Thrombolysis involves giving you injections of a type of medication called thrombolytics. Thrombolytics target and destroy a substance called fibrin. Fibrin is a tough protein that makes up blood clots by acting like a sort of fibre mesh that hardens around the blood.

Thrombolytic medications that are used in the treatment of heart attacks include alteplase and streptokinase.

You may also be given additional blood-thinning medication, such as aspirin or heparin, to prevent further blood clots from developing.

Morphine

Morphine is a painkiller that is usually given to relieve the symptoms of chest pains and to reduce feelings of stress and anxiety.

NSTEMI and unstable angina

In cases of NSTEMI and unstable angina, medication is the first option to dissolve the blood clot and thin the blood to prevent further clotting.

You may also be given an additional medication called glycoprotein IIb/IIIa inhibitors if it is thought that you have an increased risk of experiencing another more serious heart attack.

Glycoprotein IIb/IIIa inhibitors do not break up blood clots in the same way as alteplase and streptokinase, but they prevent blood clots from getting bigger. They are, therefore, an effective method of stopping your symptoms getting worse.

Depending on how serious your symptoms are, how well you respond to treatment and your general state of health, further surgery may be recommended to widen your carotid artery. This will usually be done using a coronary angioplasty.

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 blood cholesterol levels

To reduce your risk of having a heart attack, you may need to make some changes to your lifestyle.

Give up smoking

Smoking is a major contributor to many serious diseases, such as heart disease and lung cancer, and it is the biggest cause of death and illness in the UK. If you smoke, giving up is one of the best ways to help prevent having a heart attack.

If you decide to stop smoking you can get information and support on the HSE website www.quit.ie

If you are committed to giving up smoking but do not want to be referred to a stop smoking service, your GP should be able to prescribe medical treatment to help with any withdrawal symptoms that you may experience after quitting.

Take regular exercise

If you want to keep your heart healthy, it is very important to exercise regularly. Exercise will improve your circulation and help your heart to work more efficiently.

For people without a history of heart disease, 30 minutes of vigorous exercise a day, at least five times a week, is recommended. The exercise should be strenuous enough to leave your heart beating faster and you should feel slightly out of breath afterwards. Examples of vigorous exercise include going for a brisk walk and walking up a hill.

If you have had a heart attack, see Recovering from a heart attack for advice about exercise.

Diet

For a healthy heart, a low-fat, high-fibre diet, including whole grains and plenty of fresh fruit and vegetables (at least five portions a day), is recommended. Limit the amount of salt in your diet to no more than 6g (0.2oz) a day. Too much salt will increase your blood pressure. One teaspoonful of salt is equal to about 6g.

Avoid eating foods that are high in saturated fat because this will increase your cholesterol level. Foods that are high in saturated fat include:

• Meat pies
• Sausages and fatty cuts of meat
• Butter
• Ghee (a type of butter that is often used in Indian cooking)
• Lard
• Cream
• Hard cheese
• Cakes and biscuits
• Foods that contain coconut or palm oil

Eating some foods that are high in unsaturated fat can help to decrease your cholesterol level. Foods that are high in unsaturated fat include:

• Oily fish
• Avocados
• Nuts and seeds
• Sunflower
• Rapeseed
• Olive oil

Alcohol

Drinking excessive amounts of alcohol will cause your blood pressure to rise, as well as raising the cholesterol levels in your blood. Therefore, sticking to the recommended amounts of alcohol consumption is the best way to ensure that your risk of developing high blood pressure (hypertension) and having a heart attack is reduced.

The recommended daily limits of alcohol consumption are:

• 3-4 units of alcohol for men
• 2-3 units for women
• A unit of alcohol is equal to about half a pint of normal strength lager, a small glass of wine or a pub measure or spirits.

Lose weight

There are many benefits associated with losing weight. If you can reach the ideal weight for your height, it will help lower your cholesterol levels and your blood pressure. By losing weight, your risk of developing heart disease will also be significantly reduced and your life expectancy will be increased.

The most successful weight loss programmes include at least 30 minutes of daily exercise, eating smaller portions and only having healthy snacks between meals. A gradual weight loss of around 0.5kg (1.1lb) a week is usually recommended.

Other conditions

Several other medical conditions can increase your risk of having a heart attack. Two of the most common conditions are hypertension (high blood pressure) and diabetes.

Keeping other health conditions under control will help reduce your risk of having a heart attack. This means always remembering to take any medication that you have been prescribed, visiting your GP for regular check-ups and making sure that your diet is healthy.

 

A thought for you!

For less than the price of a nice couch, projector or even a desk, you could purchase a life saving piece of equipment for your organisation like an Automated External Defibrillator (AED).

The provision of automated external defibrillators (AEDs) in workplaces to assist in the prevention of sudden cardiac death should be considered. Early defibrillation using an AED is one of the vital links in the “Chain of Survival”. Ideally, wherever there is an occupational first aider(s) in a workplace, provision of an AED should be considered. The training of other employees who are not occupational first aiders in the use of AEDs is also encouraged.

Whereas it may be practicable and desirable to have an AED in every workplace, due to cost considerations it would be unreasonable to expect all employers (especially small and medium size enterprises (SMEs)) to have one on their premises, even if there is an occupational first aider present. These costs not only include the purchase price but also the vital cost of maintenance of the equipment and regular refresher training for those trained in how to use AEDs.

However, different employers at the same location, such as in shopping centres, small business enterprise centres etc., where relatively large numbers of employees or other persons are likely to be habitually present, might find it feasible to co-operate in the provision of shared equipment, training and assistance.

Training in AEDs is part of Cardiac First Response of the FETAC Level 5 Occupational First Aid.

Click here to view our range of defibrillators

Call us on 01-5079900 or 069-66006 for more information on CFR and OFA training