Is it a heart attack?

Symptoms of a heart attack, also known as a myocardial infarction (MI), 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 for an ambulance immediately. Minutes matter with a heart attack, and early treatment can be lifesaving. A heart attack occurs when blood flow to a section of heart muscle becomes blocked. If the flow of blood isn’t restored quickly, the section of heart muscle becomes damaged from lack of oxygen and starts to die.

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.

Chest pain: If you have chest pain which 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.

Other symptoms: You may have one or more of the following symptoms with or without chest pain/discomfort:

• sweating
• feeling faint
• feeling sick
• vomiting
• being short of breath.

Heart attack action plan

Heart attack 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.
• 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.

Action:

• 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.

Angina action plan

If you get angina:

• Stop what you are doing. Sit down and rest.
• If the angina still persists after a few minutes take one or two puffs of your GTN spray (eg, Nitrolingual), or half to one GTN tablet (eg, Lycinate).
• If the angina is relieved by rest, or by your GTN spray or tablet, you can resume your activities gently.
• If the angina persists, you can repeat the dose safely every five minutes.
• If the angina is not relieved after three doses in 15 minutes, dial 111 for an ambulance.

What causes a heart attack?

For many New Zealanders a heart attack happens out of the blue. But it is usually the result of two processes: the development over many years of fatty deposits (plaques) in the walls of the arteries and then 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 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.

The biggest single risk factor for heart attack is smoking. Other causes include high cholesterol, high blood pressure, diabetes, and a family history of heart disease.

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 restored to the heart muscle within 20 to 40 minutes, irreversible death of the heart muscle will begin to occur. Muscle continues to die for six to eight hours, at which time the heart attack is usually ‘complete’. The dead heart muscle is eventually replaced by scar tissue.

What is cardiac arrest?

During a heart attack, the part of the heart deprived of blood does not function properly. The pumping action could weaken, blood pressure may fall and the entire heart may become affected and cause abnormal heart rhythms.

The severity of this may cause uncoordinated electrical activity in the heart muscle, and the heart will stop beating effectively (cardiac arrest). This is life-threatening and requires immediate attention from a defibrillator that gives the heart a small shock to restore the heart rhythm. These early minutes after a heart attack are critical and the reason why prompt action is so important. 

How do I know if someone has had a cardiac arrest?

Signs of a cardiac arrest:

• the person is unconscious
• their heart has stopped beating
• their skin turns pale or blue
• you feel no pulse.

What should I do?

If the person has had a cardiac arrest (signs as above):

• act fast: get someone to call for skilled help
• start CPR (cardiopulmonary resuscitation)
• call an ambulance: dial 111 (or your local emergency number) and call the person's family doctor if you know who they are
• if you do not know how to do CPR, open the airway and start rescue breathing.

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 drugs 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 need 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).

You will be given drugs to help you recover. These may include a thrombolytic (clotbusting) 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.

For more information about the recovery process, see the Heart Foundation's booklet A Guide to Recovery after a Heart Attack (contact details under 'Further information and support' below). 

Related topics

Also see: Heart attack - minimising risks

Original material provided by the Heart Foundation of New Zealand, 2010. Edited by everybody, January 2011.