Conditions

Myocardial infarction

Myocardial Infarction — Dr Agueznai, Cardiologist in Casablanca

The best way to understand myocardial infarction is to explain its terms one by one. Let us not forget that the heart is a vital organ: by definition, an infarction is a necrosis, i.e. damage that causes the death of the affected tissue or organ. The myocardium is the name of the heart's muscle tissue, i.e. the part of the heart wall that is able to contract to keep blood circulating. A myocardial infarction is therefore necrotic damage affecting part of the heart muscle, which can no longer contract effectively. This leads to cardiac arrhythmia and heart failure, which can result in sudden death if the heart stops beating and the person does not receive defibrillation within the following minutes.

Early treatment has very significantly reduced mortality in the acute phase over the last 25 years, from more than 25% to less than 9%. As regards the death rate, even when a person receives medical care, 1 in 10 people still die within the hour and 15% die within the following year. One in 4 myocardial infarctions goes undiagnosed because it causes no symptoms, and is only detected much later, incidentally, when doctors discover the damage during a test carried out because the person has complaints or is suffering from after-effects.

What causes a myocardial infarction?

Blockage of the coronary artery is caused by an atheromatous plaque, i.e. a small mass of cholesterol that has built up and stuck to the artery walls and then broken off. This causes a clot that is carried by the blood vessels to the heart – leading to a myocardial infarction. This atheromatous plaque can also travel to the brain (causing an ischaemic stroke), to the lungs (resulting in a pulmonary embolism) or to a limb (causing arterial disease).

Certain risk factors increase the likelihood of having a heart attack: Age, as heart attacks are more common after the age of 50. Family history, i.e. having close relatives who have had a heart attack. Sex: up to the age of 50, men are more often affected, after which the difference between the sexes narrows. Smoking, which causes the arteries to narrow. High cholesterol (hypercholesterolaemia), which promotes the formation of atheromatous plaques. Diabetes, which damages the artery walls. Being overweight or obese, as excess fat increases the risk of heart attack. High blood pressure, which increases the risk of blood clots. A sedentary lifestyle and lack of physical activity.

The symptoms of a heart attack differ between men and women. In men, a myocardial infarction shows itself through: Sudden, sharp and persistent pain that starts in the chest and radiates to the left arm, the back and sometimes up to the jaw. Nausea. Dizziness, or even fainting with loss of consciousness. In women, the clinical signs of a heart attack are: Chest pain or a feeling of tightness, spreading from the chest to the left arm, back and jaw, as in men. Marked fatigue for no reason. General weakness. Breathing difficulties. Heartburn. Anxiety. A very pale complexion. Unexplained sweating.

If a heart attack is suspected, doctors first carry out a clinical examination. Then, if their suspicions are reinforced by listening to the patient's heart and chest, in addition to a blood test to detect troponins (blood markers of myocardial infarction), they order the following tests: An electrocardiogram (ECG), to assess and record the heart's electrical activity. An echocardiogram, to visualise the extent of the damaged (necrotic) tissue. A coronary angiography, to examine the coronary artery and find the cause of the necrosis.

In the event of a myocardial infarction, treatment consists of removing the blood clot responsible for the tissue damage. To do this, cardiologists perform a coronary angioplasty. This procedure widens the blocked coronary artery by inserting a small inflatable balloon via a catheter, restoring blood flow. A stent (a small metal mesh tube) is then placed in the artery to keep it open. If the patient receives care more than 90 to 120 minutes after the onset of the heart attack, doctors opt for thrombolysis, which involves giving medication to dissolve the blood clot blocking the coronary artery. Once the emergency is over, the doctor may prescribe antiplatelet treatment to prevent the risk of another heart attack. How can a myocardial infarction (heart attack) be prevented? A healthy lifestyle and frequent physical activity reduce the risk factors for having a heart attack: Stop smoking. Stop drinking alcohol. Adopt a healthy, balanced diet that is rich in fibre and low in sugar and fat, to reduce "bad" cholesterol levels and the risk of type 2 diabetes. Get back to a healthy weight by changing your diet and taking more exercise. Lower your blood pressure by cutting down on salt and avoiding stressful situations. Keep diabetes well controlled. Take part in regular sport or physical activity, especially endurance activities, to prevent fat building up in the body and to improve oxygenation.

This information is provided for guidance only and does not replace a medical consultation.