A heart attack occurs when blood flow to a section of heart muscle becomes blocked. If the flow of blood isn’t returned quickly, the section of heart muscle becomes damaged from lack of oxygen and starts to die.
Symptoms of heart attack can vary. However, if you have severe chest pain that lasts more than 15 minutes it should be assumed to be a heart attack and you should:
call 111, ask for the ambulance service and tell them you are having a possible heart attack
if available, chew one aspirin, unless you have been previously advised not to take aspirin
rest quietly and wait for the ambulance.
What are the signs of a heart attack?
Some heart attacks are sudden and intense but most heart attacks start slowly, with mild pain or discomfort that can be easily mistaken for indigestion. Symptoms often differ between men and women.
If you have chest pain that lasts more than a few minutes it may be a sign of a heart attack. The pain may:
initially come and go
be in one or both arms (more commonly the left)
go into your neck, back, jaw, stomach and abdomen
it may feel like: squeezing; pressing; tightness; fullness; pain.
Chest discomfort may not be the worst, or most noticeable, symptom in women.
Women are more likely than men to experience the following symptoms, with or without chest pain/discomfort:
being short of breath.
You may not experience all of these symptoms. If you are experiencing some of them call 111 without delay.
During a heart attack, part of the heart is starved of oxygen. This can interrupt its rhythm and can cause the heart to suddenly stop beating – known as cardiac arrest. Cardiac arrest is life-threatening and requires immediate medical attention. Read more about cardiac arrest.
Treatment for heart attack
A heart attack needs urgent medical attention. If you think you are having a heart attack:
Call 111 and ask for an ambulance and let them know you may be having a heart attack.
If available, chew one aspirin, unless you have been previously advised not to take aspirin.
How can I decrease my risk of having a heart attack?
A number of factors increase your chances of developing coronary heart disease. The more risk factors you have, the greater your chance of having a heart attack. You can’t change some of your risk factors – such as your age, gender, ethnicity and family history – but there are many others you can, such as smoking, blood pressure, weight, activity level and alcohol consumption.
Making positive changes to reduce the impact of these risk factors have will dramatically reduce your risk of cardiovascular disease and heart attack.
Credits: Heart Foundation of New Zealand + Health Navigator Editorial Team. Reviewed By: Andrew McLachlan Counties Manukau DHB (17 October 2017)
What causes a heart attack?
A heart attack can happen out of the blue, but it is more commonly the result of two processes:
the development over many years of fatty deposits (plaques) in the walls of the arteries and
a clot forming on one of the plaques.
Fatty plaques can start building up on the inside walls of your coronary arteries (atherosclerosis) at an early age. Over the years, the build up of these plaques increases and they become larger. As a result, the arteries gradually become narrower and less elastic. At this stage you may experience chest pain (also known as angina).
As the arteries narrow, there is less room for blood to flow through. If a clot forms on the plaque, the artery can become blocked, cutting off the blood supply to part of the heart muscle. This is when a heart attack occurs.
What happens during a heart attack?
In a heart attack there is a sudden blockage of a coronary artery by a blood clot. Coronary arteries are blood vessels that supply the heart muscle with blood and oxygen. Blockage of a coronary artery deprives the heart muscle of blood and oxygen, causing injury to the heart muscle.
Injury to the heart muscle causes chest pain and the sensation of chest pressure. If blood flow is not returned to the heart muscle within 20 to 40 minutes, irreversible death of the heart muscle will begin to occur. Muscle continues to die for 6 to 8 hours, at which time the heart attack is usually ‘complete’. The dead heart muscle is eventually replaced by scar tissue.
A number of factors increase your chances of developing coronary heart disease. The more risk factors you have, the greater your chance of having a heart attack.
Risk factors you can't change
Your chance of getting a heart attack increases with age.
Most people who die from a heart attack are 65 years or older.
At older ages, women who have heart attacks are more likely than men are to die from them within a few weeks.
Men have a greater risk of heart attack than women do, and they have attacks earlier in life.
In New Zealand, people of Maori, Pacific and Indian subcontinent ethnicity are at greatest risk of heart disease.
If an immediate male relative, i.e., your father or brother, has had a heart attack or stroke before the age of 55, or if an immediate female relative, i.e., your mother or sister, has had one before the age of 65, you are at greater risk of developing heart disease.
If both parents have had a heart attack or stroke before the age of 55, your risk of developing heart disease can rise to 50% compared to the general population.
However, having a family history of coronary heart disease doesn't mean that you'll develop it. This is especially true if your family member smoked or had other risk factors that were not well treated.
Making lifestyle changes and taking medicines to treat risk factors can often lessen genetic influences and prevent or delay heart problems.
Risk factors you can change
The biggest single risk factor for heart attack is smoking.
A smokers' risk of developing heart disease is much higher than that of nonsmokers. If you smoke, you are 2 to 4 times more likely to suffer a heart attack.
Exposure to other people's smoke increases the risk of heart disease even for nonsmokers.
Having diabetes hugely increases your risk of heart disease, especially if your blood glucose levels are not controlled.
At least 68% of people aged 65 years of age or over with diabetes die of some form of heart disease.
If you have diabetes, it is very important to work with your healthcare provider to manage it and control any other risk factors you can. Learn more about diabetes – how to improve your blood glucose control if you already have diabetes or how to prevent getting diabetes.
As blood cholesterol rises, so does risk of coronary heart disease.
When other risk factors (such as high blood pressure and tobacco smoke) are present, this risk increases even more.
A person's cholesterol level is also affected by age, sex, heredity and diet.
High blood pressure increases the workload placed on the heart, causing the heart muscle to thicken and become stiffer. This stiffening of the heart muscle is not normal and causes the heart not to work properly. It also increases your risk of stroke, heart attack, kidney failure and congestive heart failure.
When high blood pressure exists with obesity, smoking, high blood cholesterol levels or diabetes, the risk of heart attack or stroke increases even more.
People who have excess body fat, especially a lot of fat around the waist, are more likely to develop heart disease even if they have no other risk factors.
Losing weight (3 to 5% reduction in body weight) can significantly lower your risk of heart disease and reduce other risk factors such blood pressure, cholesterol, and blood glucose.
Lack of physical activity
An inactive lifestyle is a risk factor for coronary heart disease.
Regular, moderate-to-vigorous physical activity helps reduce the risk of heart and blood vessel disease.
Even moderate-intensity activities help if done regularly and long term.
Physical activity can help control blood cholesterol, diabetes and obesity, as well as help lower blood pressure in some people.
Different people respond to stress differently and stress may affect the risk factors that contribute to heart disease for example, people under stress may overeat, start smoking or smoke more than they otherwise would. Learn more about stress and managing stress.
Excess alcohol consumption
Drinking too much alcohol can increase your risk factors such as raise blood pressure, increase a type of cholesterol (triglycerides), and contribute to obesity. However, there is a cardioprotective effect of moderate alcohol consumption.
If you drink, limit your alcohol consumption to no more than two drinks per day for men and no more than one drink per day for women.
To learn more and to build your own heart risk profile based on factors such as your age, gender, cholesterol levels, smoking, blood pressure, family history and past history. See Heart risk assessment
Heart attack action plan
Minutes matter with a heart attack and early treatment can be lifesaving.
Know the warning signs
Heavy pressure, tightness, crushing pain or unusual discomfort in the centre of the chest lasting more than 10-15 minutes. It may stop or get less intense and then return. This symptom may not be the most noticeable symptom, especially in women.
Pain spreading to the shoulders, neck, jaw and/or arms.
These may be accompanied by sweating, a sick feeling in the stomach, dizziness and shortness of breath. These symptoms are the ones women most commonly notice.
Dial 111, ask for the ambulance service and tell them you are having a possible heart attack.
If available, chew one aspirin, unless you have been previously advised not to take aspirin.
Rest quietly and wait for the ambulance.
Get it checked out
People often are not sure what's wrong and wait too long before getting help. The warning signs of a heart attack vary and it is possible to have no pain (especially in women and people who have diabetes) or the only sign may be indigestion-type pain.
Even if you're not sure it's a heart attack, have it checked out. Fast action can save lives. Calling 111 is almost always the fastest way to get lifesaving treatment. Emergency medical services staff can begin treatment when they arrive – up to an hour sooner than you'd get treatment if you go to hospital by car.
What happens in the ambulance?
Ambulances attending people with chest pain generally have a paramedic crew member trained in coronary resuscitation. They will also have all the appropriate equipment, the medications they will need as well as a defibrillator, which can deliver a measured electric shock to the heart, should a dangerous heart rhythm occur.
They will also have an ECG (electrocardiogram) monitor and set up an intravenous line to enable the paramedic to give you drugs quickly and effectively. You may be given aspirin and pain relief by the ambulance officer.
What happens in hospital?
Once at the hospital, you will be treated in the emergency department. The doctors will perform tests to find out whether or not you have had a heart attack. These tests include an ECG and blood tests for cardiac enzymes (these are released into your body by damaged heart muscle cells). Read more about heart disease tests.
You will be given medication to help you recover. These may include a thrombolytic (clot busting) drug which will help to break down the clot. You may need a procedure called an angioplasty, to widen the narrowing in a coronary artery.
Once your condition is stable you will be transferred to a specialist ward called the Coronary Care Unit (CCU). As your heart becomes more stable, the ECG monitoring will be taken away. You will be able to walk gently around the ward with assistance.
You may be given medication as well as being prescribed aspirin, which helps to reduce your risk of more clots developing. Further blood tests will be required before you are able to go home. If there are no more problems you can look forward to going home in a few days.
What happens when I am discharged from hospital?
Cardiac rehabilitation is an important part of recovery. It can significantly increase your chances of recovering successfully and help in preventing another heart attack.
Information for healthcare providers on heart attacks
The content on this page will be of most use to clinicians, such as nurses, doctors, pharmacists, specialists and other healthcare providers.
Checklist: Patient presenting with acute chest pain in primary care
Perform an ECG in all patients where the possibility of a cardiac cause of chest pain cannot be reasonably excluded
If a ST segment abnormality, particularly ST segment elevation, is detected or ECG is inconclusive but suspicion of a cardiac cause remains, refer to hospital immediately and alert the on-call cardiologist or emergency department consultant
While awaiting transfer:
Monitor blood pressure, heart rate and oxygen saturation
Give sublingual glyceryl trinitrate* and IV morphine (if required) for pain relief
Give 300 mg aspirin
Give 300 mg clopidogrel if evidence of ischaemia on ECG or elevated troponin levels (see number 4)
Only administer oxygen if the patient is breathless, oxygen saturation is <93%, has heart failure or is in cardiogenic shock
A blood sample for measuring troponin levels may be considered if time and clinical circumstances permit
If transfer will be delayed for more than two hours and patient has ST segment elevation, initiate tenecteplase,** followed by enoxaparin, if available
* Sublingual GTN should be used with caution in some patients, e.g. those who are cardiovascularly unstable. See NZF for a full list of cautions and contraindications. ** Tenecteplase is usually only available in rural practices.