Heart Attack

Definition of a heart attack

A heart attack takes place when the blood supply to the heart muscle is jammed, which is usually the result of a blood clot in the coronary artery. Blockages in the stream of blood often cause irregular heart rhythms named arrhythmias, which impairs the ability of the heart to pump blood around the body. Heart attacks can cause sudden death or permanent injury to the heart muscle if the blockage isn’t treated quickly. The medical name for a heart attack is myocardial infarction.

This is a very serious, life-threatening condition so it is important to know the early warnings and symptoms of a heart attack, as quick treatment can make the difference between life and death.

Every year more than 1 million US inhabitants and over 100,000 people in the UK suffer a heart attack. However, death rates have fallen considerably over the last decade thanks to developments in technology and science.

Emergency treatment can often stop irregular heart rhythms but it is important to seek urgent medical help as quickly as possible. The death rate for heart attacks is highest among those people who do not receive treatment within an hour of suffering a heart attack.

A heart attack is classed as a medical emergency, so it is important to contact the emergency services as soon as possible if you believe you, or somebody else, is suffering from a heart attack. Rapid treatment for a heart attack can save lives and stop long-lasting injury to the heart muscle.

Other names for a heart attack:

Myocardial infarction (also known as MI)
Acute myocardial infarction (or AMI)
Acute coronary syndrome
Coronary thrombosis (coronary clot)
Coronary occlusion

What can lead to a heart attack?

In most cases, heart attacks are the result of a blood clot blocking the blood supply to the heart muscle. Clots occurring within the coronary arteries prevent the blood from reaching certain parts of the heart, which means that the heart is starved of oxygen. If the block is left untreated the heart muscle cells will eventually die.

Coronary artery disease (CAD) is the main reason for heart attacks, which occurs as a result of the coronary arteries becoming harder and narrower due to a build-up of fatty deposits inside the artery walls (this is known as atherosclerosis). Over the course of time the collection of fatty deposits inside the artery walls causes the following problems:

Narrowing of the arteries, meaning less blood is able to run to the heart.
Complete blockage of the artery, preventing blood from reaching the heart muscle.
The formation of blood clots, which obstruct the blood supply to the heart.

In less common cases, heart attacks can be caused by a spasm of the coronary artery. A spasm is a very severe tightening, which can obstruct the blood flow through the artery. Spasms in the coronary artery can occur in people who do not have coronary heart disease and may be caused by:

Stress
Taking drugs, e.g. cocaine
Exposure to very cold temperatures
Smoking

Risk factors that contribute to heart attacks and heart disease

Several risk factors have been identified for heart attacks. These factors increase the risk of suffering a heart attack, but they do not necessarily mean that an individual will actually have a heart attack.

Risk factors you are unable to modify include:

Age - the risk of suffering a heart attack raises with age and men aged over 45 and women aged over 55 have the biggest threat of suffering a heart attack.
Family history of premature heart disease - if you have a history of heart attacks in your family, you will have a higher risk of suffering a heart attack. If you have a close male relative under the age of 55 or a female relative under the age of 65 with heart problems, your risk will be higher.
Personal history of coronary artery disease, angina or heart attacks.

Risk factors you can change:

Smoking
Diabetes (in the case of type 2 diabetes)
Inactivity
Obesity
High blood pressure
High cholesterol (caused by eating a lot of fatty foods)

Symptoms and signs of a heart attack

Pain and discomfort in the chest - most people who suffer a heart attack experience pain in the centre of the chest, which either comes and goes or persists for a short period of time. The feeling may resemble tightening, fullness and a squeezing sensation. Some people also compare it to severe heartburn or indigestion.
Pain in other parts of the body - pain can radiate from the chest to other parts of the body, including the arms, neck and jaw.
Numbness in the arms, which can be one or both limbs.
Difficulty breathing- this usually occurs in combination with chest pain, but it can come on before pain.
Additional symptoms, including nausea, dizziness, sweating and feeling light-headed.

Symptoms vary according to the individual and even if the same person has two heart attacks they may experience different symptoms. Some people do not have any symptoms, and this is known as a silent heart attack.

The signs of angina are often comparable to signs of a heart attack. If you have been diagnosed with angina and you feel that your symptoms are getting worse, see a doctor as quickly as possible.

It is important to recognise the symptoms of a heart attack, in order to get help as quickly as possible in the event of suffering a heart attack or coming across another person who is having one. If you believe you are suffering a heart attack or somebody else shows the signs of a heart attack, get emergency medical help as soon as possible. This could save lives and stop permanent injury to the heart. Lifesaving treatment can be provided by ambulance staff on the journey to hospital.

How do you diagnose a heart attack?

The diagnostic process for a heart attack can start as soon as you contact the emergency services. If you feel you are suffering a heart attack it is important to get emergency aid as quickly as possible. Do not wait because you are unsure whether or not it is a heart attack. When you reach the emergency department doctors will try to diagnose a heart attack as quickly as possible and will take the following factors into account:

Your age
Your symptoms
Your medical history
Family history
Test results

Tests used to diagnose a heart attack will include:

ECG (electrocardiogram) - the ECG test is implemented to determine the rate and rhythm of the heartbeat. A 12-lead EKG is used to diagnose a heart attack.
Blood tests - enzymes, known as markers or biomarkers, are released into the blood when cells die. Measuring the markers can help to determine how much damage has been inflicted on the heart. Blood tests are generally repeated at regular periods to monitor changes in the results.

Blood tests include:

Troponin test - this test measures the level of troponin within the blood and is regarded as the most accurate indicator of a heart attack. The test is also used to assess how much damage has been made to the heart.
CK or CK-MB test - this test monitors the level of different types of creatine kinase found within the blood.
Myoglobin - this test confirms the existence of myoglobin in the blood; myoglobin is released into the bloodstream when the heart is damaged or injured.
Nuclear heart scan - this form of scan uses radioactive tracers to outline the major blood vessels and heart chambers and the scan will show injury to the heart.
Cardiac catheterisation - this involves passing a flexible, thin tube (a catheter) through an artery into the arm or groin to the coronary arteries. The test allows doctors to determine the pressure inside the heart chambers and check the current of blood. It also enables doctors to gather blood samples from the heart.
Coronary angiography- this test is generally conducted with a cardiac catheterisation. The test involves injecting coloured dye into the arteries to allow doctors to see how the blood is flowing through the heart and highlight any obstructions.

How do you treat a heart attack?

A heart attack should always be treated as a medical emergency and the sooner a heart attack is treated the lower the risk of lasting injury to the heart. Treatment for a heart attack is often provided by emergency medical staff while the patient is on their way to the emergency department.

At the hospital

At the hospital, if you are suffering a heart attack, doctors will act swiftly to re-establish the flow of blood towards the heart and observe your vital signs very closely. It is vital to restore normal blood supply to the heart, as the cells will start to die if they are starved of oxygen. The main treatments used to re-establish blood supply are clot-busting medication and a surgical procedure known as an angioplasty.

Clot-busting medication (thrombolytic drugs) - these drugs are used to break-down clots that prevent blood from flowing freely to the heart. When these drugs are given quickly post-heart attack, they can limit injury to the heart and prevent permanent damage. Clot-busting medication is most effective if given within an hour of the first signs of a heart attack.
Angioplasty - an angioplasty is a procedure used to open up the arteries and a stent may be put in place to keep the artery open.
Coronary artery bypass surgery - this procedure uses veins or arteries from other parts of the body to bypass the blocked area of the coronary artery and subsequently improve blood flow.

In hospital patients who have had or are suffering a heart attack are usually treated in specialist heart units called coronary care units (CCU). The CCU is specifically equipped to treat patients and monitor their condition to test for alterations or complications. The patient’s vital signs, including their pulse oximetry (the level of oxygen within the blood) and blood pressure, will be studied and the EKG will be used to check for irregular heart rhythms and problems with heart function.

Medication

Medication used to treat heart attacks may include:

Beta-blockers - these are designed to reduce pressure on the heart by decreasing the amount of work the heart has to do. Beta-blockers lower the blood pressure and can also be used to treat angina and to prevent further heart attacks in patients who have previously suffered a heart attack. Beta-blockers can also be used to treat patients with an irregular heart rhythm.
Angiotensin-converting enzyme (ACE) inhibitors - these drugs lower blood pressure and help to relieve strain on the heart.
Nitrates - these drugs help to ease pain and relax the blood vessels.
Anticoagulants - these drugs help to prevent clotting by thinning the blood.
Antiplatelet medication - these drugs help to prevent platelets clustering together to create clots and are administered to people who have experienced a heart attack and those who have had an angioplasty and experience angina.
Glycoprotein llb-llla - these are very strong antiplatelet medications given intravenously.
Pain-relief medication.
Medication to reduce anxiety.
Oxygen therapy.
Medication to treat irregular heart rhythms.

The length of time you stay in hospital after a heart attack depends on the severity of your condition. Most people stay in hospital for several days following a heart attack. During your time in hospital your vital signs will be monitored closely and you will be given treatment for any difficulties that occur due to the initial heart attack. While you are in hospital or shortly after you return home it is common to have additional tests, including:

Echocardiogram - this test uses ultrasound technology to generate a detailed image of the heart, which can be viewed on a video screen. An echocardiogram indicates how healthy the heart is functioning.
Exercise stress test - this test indicates how well the heart works when it is under pressure and requires a higher level of oxygen. Blood pressure and EKG readings are monitored before, during and after you exercise, and the test carries on until the patient reaches a heart rate decided by the doctor. However, exercise is stopped if the patient experiences chest pain.

Heart rehabilitation

Your doctor may advise cardiac rehabilitation following a heart attack to aid your recovery and reduce the risk of more heart attacks in the future. Cardiac rehabilitation is beneficial for almost everyone that has suffered a heart attack.

A cardiac rehabilitation team may be made up of:

A cardiologist (a heart specialist)
A surgeon
Your family doctor
Nurses
Physiotherapist
Dietician
Psychologist
Exercise specialists

Rehab generally contains two key elements:

Exercise and training - to assist you in exercising safely and enjoying exercise. Your exercise regime will take a number of factors into consideration including your age, general health, interests and fitness levels.
Education and counselling - this will help you to be aware of your heart condition, provide you with important information about how you can reduce the risk of further heart problems and provide support to deal with anxiety and stress.

After you leave hospital

After you leave hospital you will be advised to follow a rehabilitation regime and see doctors on a regular basis so they can monitor your condition. You may be advised to take medication and make changes to your lifestyle. It is important that you follow the doctor’s instructions for taking medication. Most people take medication on a daily basis following a heart attack, which may include:

Aspirin - this is used to thin the blood to reduce the risk of clotting.
Medication to lower blood pressure or cholesterol.
Other medication to reduce stress on the heart.

What steps can I take to stop a heart attack?

The majority of heart attacks are the result of coronary heart disease. You can reduce the risk of coronary heart disease by knowing the risk factors, living a healthy lifestyle and taking steps to decrease your risk of suffering a heart attack. Even if you have previously suffered a heart attack making changes to your lifestyle can still be beneficial.

Lifestyle changes

Making simple changes to your lifestyle could have a hugely positive impact on your general health and help to lower your chances of coronary heart disease and other serious health conditions. The following lifestyle choices will help to decrease your chances of suffering a heart attack:

Give up smoking.
Drink in moderation (stick to the recommended daily guidelines).
Eat a healthy, balanced diet containing plenty of wholegrain foods, fruit and vegetables, and avoid eating fatty, processed and fried foods on a regular basis, as these are high in cholesterol.
Exercise on a regular basis and aim for at least 30 minutes of moderate exercise 5 times per week. Check with your doctor about exercise if you have a history of heart problems or have suffered a heart attack in the past.
Lose weight, especially when you are classed as obese or overweight, and this can be done most effectively by eating well and exercising regularly.

Treating related conditions

Many conditions increase the risk of suffering a heart attack and treating them will help to reduce the risk of a heart attack. These conditions include:

High blood cholesterol
High blood pressure
High blood sugar and diabetes

Your doctor will be able to advise how to lower your blood pressure and cholesterol, and provide information about reducing your blood sugar level and keeping blood glucose levels stable.

Preventing a heart attack in the future

If you have previously suffered a heart attack there are things you can commit to in order to reduce the risk of suffering a second or more heart attacks. It is essential that you keep to your doctor’s guidance about healthy living, taking medication and exercising. Following your doctor’s advice will help to prevent complications and further damage and reduce the risk of another heart attack.

It is important to have plans in place in the event that you experience symptoms and early warning signs of a heart attack. These include being aware of the symptoms and signs, knowing where your local hospital is and making sure you know how to contact the emergency services. It is worth noting that the signs of another heart attack may possibly be different from the previous heart attack.

Life after you have suffered a heart attack

Many people survive heart attacks and go on to live a healthy, long life. However, it is important to follow doctors’ advice about lifestyle changes, taking medication and eliminating risk factors. The aims for patients who have already suffered a heart attack should be:

To stop another heart attack.
To recuperate and continue normal day to day life.
To prevent complications.

All patients who have suffered a heart attack will be advised to attend regular check-ups and have tests to enable doctors to keep an eye on their progress and detect any complications or problems as early as possible. It is likely that your doctor may also advise you to make changes to your lifestyle, adapt your diet, follow a cardiac rehabilitation programme and take medications.

Exercise is very beneficial for health but it is important that you adhere to your doctor’s instructions – as you do not want to place your heart under too much stress. Exercise helps to lower blood pressure and cholesterol and is also very important for people who need to lose weight.

Returning to normal activities

The majority of people can return to a normal daily routine after a heart attack. But you should ask your doctor for advice about when it is safe to return to work, start an exercise programme, drive and travel by air and engage in sexual activity.

Most people who do not have complications are able to go back to their normal activities after a few weeks.

Anxiety and depression following a heart attack

Many people feel anxious following a heart attack and live in fear of having another in the future. Your doctor will be able to provide information about support systems and you should talk to them if you feel anxious or have symptoms of depression. You may be advised to take medication and spend time doing activities that relax you and make you feel happy.

Knowing when and how to ask for medical treatment

If you have previously suffered a heart attack your risk of having another attack in the future will be increased. It is important to have a plan in place in the event of suffering another heart attack. This involves being aware of the symptoms and early warning signs and ensuring that your friends and relatives are aware of the symptoms and know what to do in the event of you falling ill. Many people suffer from angina, but if your angina is getting worse or the pain is taking longer to subside, even when you take medication, see your doctor. If you are not sure whether the pain you have is caused by angina or a heart attack, contact an ambulance and wait for help. It is better to err on the side of caution, as fast treatment can make a huge difference and stop lasting injury to the heart.

Heart attack summary

A heart attack happens when the blood cannot run to the heart, causing the heart to be starved of oxygen, which is most commonly the result of a blood clot. Blockages can cause irregular heart rhythms and prevent the heart from pumping properly, which may result in permanent damage.
More than 1 million people in the USA and 100,000 people in the UK suffer a heart attack every year and survival rates are highest among those that have immediate treatment.
Signs and symptoms of a heart attack include chest pain, pain in the arms, neck and jaw, numbness in one or both arms, breathing difficulties, nausea and dizziness.
It is important to seek medical help as quickly as possible if you have symptoms of a heart attack. Many people wait and this can reduce the chance of survival and increase the risk of complications.
The level of injury to the heart is dependent on what quantity of the heart was starved of oxygen and how quickly treatment was given.
Heart attacks affect both men and women.
Risk factors for heart attacks include age, family history and personal history of heart problems. Other changeable factors include high blood pressure, being overweight or obese, smoking, having a sedentary lifestyle and eating a lot of fatty processed foods.
The diagnostic process can start as soon as emergency paramedics reach the scene and treatment will continue at the hospital.
If you are suffering a heart attack doctors will try to reinstate the blood supply to the heart as quickly as possible.
Treatment options for a heart attack include medication, lifestyle changes, rehabilitation and follow-up tests.
Most people are able to return to normal activities within a small number of weeks of receiving treatment for a heart attack.
If you have suffered a heart attack it is important to have a plan in place in the event that you have another attack in the future. You should be aware of the symptoms and signs and tell your family and friends how to react if you do experience symptoms.
A heart attack is a medical emergency and it should always be treated as such. The quicker a heart attack is treated the better.