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Myocardial infarction (heart attack)

A myocardial infarction, or heart attack occurs when a portion of the heart muscle is deprived of oxygen for too long and dies.

A man clutching his chest

Like all muscles, the heart requires oxygen to function. It receives this via the two coronary arteries and it is when one of these becomes blocked that the heart tissue is starved of oxygen (cardiac ischaemia). 

In most cases this happens when anatherosclerotic plaque – part of the fatty arterial wall build-up associated with coronary artery disease – ruptures, creating a blood clot that then blocks the already narrowed artery. If the ischaemia lasts too long, myocardial infarction – a condition characterised by the death of parts of the heart muscle – occurs. 

The coronary artery disease that usually causes myocardial infarction is often linked to unhealthy lifestyles. Smoking, obesity, high blood pressure (hypertension), high cholesterol and uncontrolled diabetes are all major risk factors.

What are its symptoms?

The Heart and Stroke Foundation South Africa (HSF) cautions that myocardial infarction symptoms may vary from person to person, but that signs to look out for include:

  • Chest pain: This may feel like a crushing sensation, tightness, pressure or unusual discomfort in the central chest region or it may feel similar to heartburn. Pain commonly radiates into the left arm, but may also be felt in the neck, jaw, back and right arm
  • Dizziness, feeling faint and shortness of breath
  • Cold sweat
  • Nausea
  • Fatigue and general feeling of being unwell

It is vital to treat these symptoms as a medical emergency and seek help as quickly as possible.

How is it diagnosed? 

Diagnosis of a myocardial infarction is usually a matter of urgency that requires an immediate visit to a hospital’s emergency room, as any delay can result in further irreparable damage to the heart muscle. 

There are two types of test that can confirm a heart attack: 

  • An electrocardiogram is the first, whereby electrodes attached to the skin are used to record whether there are any abnormalities in the way the heart is conducting its electrical impulses (a sign of heart muscle damage). 
  • Blood tests to look for the presence of the cardiac enzymes, which are released by dying heart tissue, leading to elevated levels in the blood following a myocardial infarction. 
  • Additional tests like angiograms, X-rays and echocardiograms may be used to determine where the blockage occurred and the extent of the damage to the heart muscle.

What are your treatment options? 

Myocardial infarction treatment is focused first on restoring blood flow to the heart as swiftly as possible. 

Various clot-busting medications are administered to help dissolve the clot or prevent new ones from forming – aspirin is one common household medication that can be used in an emergency situation while waiting for help to arrive. 

Painkillers and drugs to dilate the arteries and decrease blood pressure may also be used. 

Myocardial infarction frequently requires surgery, either to insert a special balloon called a stent into the blocked artery to widen it (coronary angioplasty) or to bypass the blockage by using blood vessels harvested from other parts of the body (coronary bypass surgery).

Can it be prevented? 

There is a significant lifestyle factor that contributes to the development of coronary artery disease, which is usually the precursor for a myocardial infarction. As such, there are many cases in which prevention of myocardial infarction may be possible, simply by making healthier choices. 

These include: 

  • Not smoking
  • Keeping your weight within a healthy range
  • Eating a balanced diet
  • Exercising regularly and managing other health conditions that may increase your risk. 

Those already at risk or recovering from a previous heart attack should discuss medication options to help reduce their risk with their healthcare provider.

For more info contact the Heart and Stroke Foundation South Africa.

IMAGE CREDIT: 123rf.com

The accuracy of this information was checked and approved by physician Dr Thomas Blake in July 2016
Read More: Heart Disease Super Section