Heart Attack (Myocardial Infarction/ Coronary Thrombosis)

What is a heart attack?

The heart is responsible for pumping blood around our body. However like all other muscles, it requires its own blood supply. The coronary arteries are responsible for this. The heart is surrounded by three major coronary arteries. If a blood clot develops in one of these arteries, the blood supply to an area of the heart muscle will stop, starving the muscle of oxygen – and a heart attack will occur.

A blood clot can occur if the arteries become damaged, for example by atherosclerosis (hardening of the arteries). Atherosclerosis involves the build up of plaques in the lining of the arteries. If a break occurs in one of these plaques, a blood clot forms at the site and blocks off the blood supply to part of the heart muscle.

A heart attack is also known as myocardial infarction or coronary thrombosis.

What are the symptoms of a heart attack?

The usual symptoms a person may feel are:

  • Pain or a feeling of pressure behind the breast bone (sternum) or the left-hand-side of the chest, which lasts 10 minutes or more or goes but then comes back
  • Pain spreading to the shoulders, necks, arms or hands. The pain often radiates to the left arm
  • Pain may also spread to the jaw, ear or stomach
  • A feeling of tightness in or around the throat
  • Shortness of breath, even at rest
  • Ashen skin
  • Fainting and dizziness
  • Nausea or vomiting
  • Intense sweating
  • Frequent angina attacks that are not caused by exertion.

It is important to state that a person does not need to be exhibiting all of these characteristics to be having a heart attack. Some people do not experience any symptoms – or only have mild symptoms during a heart attack. So if a person is only showing one or two signs, do not ignore it – it may still be a heart attack. The more signs a person does show however, the more certain you can be that it is a heart attack.

What are the risk factors associated with a heart attack?

Apart from atherosclerosis, there are a number of things which can increase the chances of a person having a heart attack:

  • Age – risk of heart attack increases with age
  • Male gender
  • Family history of heart disease
  • Smoking
  • Diabetes Type 1 and Type 2
  • High blood pressure (hypertension)
  • High cholesterol levels
  • Stress
  • Obesity
  • Lack of exercise.

Risk factors for heart attack

I suffer from angina. How can I tell the difference between an angina attack and a heart attack?

Some of the characteristics of an angina attack are similar to those of a heart attack, such as pain or discomfort in the chest, which can sometimes spread to other areas such as the arms or jaws.

However most angina attacks occur after a person has exerted themselves, for example if they have taken part in an active sport. If pain occurs without exertion, it may be a heart attack.

Also most angina attacks only last a couple of minutes. After a rest, they go away. If the pain refuses to go away, or goes but comes back, it may be a heart attack.

If you normally take medication for your angina but find this time it does nothing to ease your discomfort, you may be suffering a heart attack.

What should I do if I, or somebody I know, appears to be having a heart attack?

The most important thing is to seek medical help immediately. Ring an ambulance and tell them it is a coronary problem so they know your call is a priority.

If you are having the heart attack and are on your own, wait for the ambulance to get to you. Do not drive as the condition may rapidly deteriorate. Do not exert yourself in any way and try to remain calm. If you are not allergic, take an aspirin (of 300mg strength). Make sure you tell the medical crew exactly what you have taken.

If somebody else appears to be having a heart attack, ensure that the person stops what they are doing and rests. Try to keep the person calm. While it is essential that they are treated as soon as possible, use your common sense. An ambulance can get through traffic much faster then you can, so only try to drive the person to a hospital if you are positive you can get there before an ambulance reaches you, or if you have no phone to contact anybody.

If the person loses consciousness, you may have to begin CPR. Visit our Emergency Resources section for more advice on how to deal with someone having a heart attack.

How is a heart attack treated?

When you arrive in hospital, a heart attack will normally be confirmed with an electrocardiograph (ECG) or blood tests. Other tests – such as an echocardiogram and a coronary angiogram – may also be carried out later on to find out why you had a heart attack.

If the heart has stopped, a device called a defibrillator will be used to administer an electric shock to the heart, to try and restart it. A dose of aspirin will immediately be given to reduce any blood clot, and another type of drug called a thrombolytic, which works to dissolve blood clots, may also be administered. These drugs ideally need to be given within an hour of symptoms starting.

After the heart attack, you may be prescribed other drugs in order to reduce the chance of another attack occurring. These may include anti-platelet or anti-coagulant drugs, beta-blockers, ACE inhibitors and statins.

Surgery may also be required in some cases and may involve either a bypass or an angioplasty to open up the blocked artery.

What can I do to reduce the risk of having a heart attack?

Smoking is a massive contributor to the development of heart disease. It raises blood pressure, promotes the build up of plaque in the arteries (which can lead to atherosclerosis), damages blood vessels, and lowers the levels of HDL ("good" cholesterol). The blood is more likely to clot in a smoker than a non-smoker, so if you want to lower your chances of having a heart attack, QUIT smoking.

A high cholesterol level is one of the major contributors to coronary heart disease. Therefore your cholesterol level should be checked on a regular basis from the age of 20. In order to avoid or reduce a high cholesterol level, you should maintain a healthy and varied diet, avoiding saturated fats such as those found in red meat. Be sensible with your cooking methods as well. Avoid frying or roasting your food. Grilling and boiling is highly recommended. Replace full-fat products, such as whole milk, with low fat products.

Regular exercise is essential, as it can help control a person's weight, lower their blood pressure and increase the levels of HDL ("good" cholesterol) in their body. The exercise does not have to be strenuous. For example, if you suffer angina attacks after physical exertion, make something non-strenuous like walking your regular exercise. Something as simple as getting off the bus one stop early every day may help.

Know your family history. A high cholesterol level may run in the family, therefore you may have to be more vigilant then others when it comes to heart disease. Also women need to be particularly careful once they reach the menopause, because their chances of developing heart disease increase at this time. This is because the hormone oestrogen is one protector against heart disease and after the menopause, levels of it decline.

Stress has been shown to increase the levels of chemicals within the body that can potentially damage the heart and blood vessels. Therefore stress may, in some cases, increase the risk of a heart attack. If you have a condition that can affect the heart, follow your doctor’s advice regarding treatment.

My wife has just been released from hospital after suffering a heart attack. What can I do to help her?

Physically, the most important thing you can do is ensure that she rests. Do not allow her to exert herself. Her heart needs time to recover from the attack.

It is also extremely important that you are aware of the possible mental consequences. Your wife may become depressed and this may be for a number of reasons. She may be frightened of a relapse, or she may be unused to taking things slowly, and so get increasingly frustrated at having to rest. Whatever the cause, if you suspect she is depressed, talk to her. Depression won't go away on its own, and may require some professional advice or treatment.


Visit the irishhealth.com Heart Disease Clinic for more information and advice on all types of heart problems.

Reviewed: December 11, 2006