Heart Infarction a.k.a. Heart Attack (Myocardial Infarction)
Myocardial infarction or heart attack is the destruction of a more or less extensive area of the heart muscle. It is the consequence of the obstruction of a coronary artery. While it is impossible to act on certain risk factors and others can be reduced.
Atherosclerosis as the main cause of heart attack
Myocardial infarction is the death of part of the heart muscle (or myocardium). This happens when one of the coronary arteries, which supply blood to the heart, becomes blocked. The corresponding area of the heart, suddenly deprived of blood and therefore of oxygen, suffers and is damaged beyond repair.
The main cause of heart attacks is atherosclerosis, which begins with the formation of atherosclerotic plaques, made up of cholesterol, fibers and cellular debris, on the walls of the arteries. These plaques cause chronic inflammation in the wall. This weakens them. The plaque may eventually rupture, causing a blood clot to form that blocks the artery (the thrombus).
What are the risk factors for heart infarction?
Atherosclerosis as the main cause of infarction. The main risk factors for myocardial infarction are:
- High cholesterol.
- High blood pressure.
- Alcohol consumption.
- Obesity and overweight.
- Sedentary lifestyle and lack of physical activity.
- An unbalanced diet.
- The stress.
We must add factors on which we cannot act, such as family history (if the father, mother, brother or sister has presented an early cardiovascular disease), gender (men are more at risk than women) and age (from age 50 for men, 60 for women).
What are the symptoms?
It is crucial to notify the emergency services (call 112 international emergency number) in the face of the signs suggestive of a heart attack. These signs can vary and sometimes turn out to be painless. In men, the pain grips the chest, radiates to the arm, the jaw, and persists despite taking analgesics.
Sometimes this pain can be accompanied by other symptoms, such as anxiety, shortness of breath, nausea, paleness, etc.
In women, the infarction can be revealed by fatigue, a feeling of imminent death, palpitations and nausea.
How is the diagnosis made?
The diagnosis is made by clinical examination, but also by the electrocardiogram (ECG), a tracing obtained by recording the electrical activity of the heart.
What treatment should be put in place?
The goal for doctors is to unclog the artery and restore blood flow to the heart as quickly as possible. The prognosis depends on the extent of the affected area (“time is muscle”).
The emergency teams inject blood-thinning drugs on the spot. Then, the patient is referred to an interventional cardiology service, where the position of the thrombus is visualized in the affected coronary artery thanks to a coronagraphy.
Then, an angioplasty is performed, a technique that involves widening the artery using a small balloon that is inflated. It is usually followed by the placement of a stent (a small circular spring that keeps the artery open).
In very rare cases, the procedure first involves injecting a drug into a vein in the arm to dissolve the thrombus, without coronary angiography or immediate stenting. It’s thrombolysis. Performed within 2-3 hours after the onset of pain, this technique is very effective and unclogs the coronary artery in 70% of cases.
Risk of recurrence
The risk of recurrence then constitutes a major risk. To minimize it, the key is to understand what factors led to the first heart attack, for example undetected hypercholesterolemia or smoking, and then to take care of them. It is also important to avoid the formation of a new thrombus at the level of the stent itself. Several classes of drugs are given to patients, such as beta-blockers, antiplatelet agents, anti-cholesterol and antihypertensives.
FACTORS FAVORING MYOCARDIAL INFARCTION
Myocardial infarction, like other cardiovascular diseases (diseases of the heart and arteries), mainly is caused by fatty deposits on the walls of the arteries. The disease mainly affects men over 55 and women between 65 and 70. But the infarction can occur earlier if the cardiovascular risk factors are accumulated.
Cardiovascular risk factors that cannot be controlled
Age and gender
The probability of having a cardiovascular accident increases after age 50 in men and after age 60 in women.
Women are four times less likely to have a heart attack than men before menopause. However, the proportion of young women who are victims of it is tending to increase, in particular due to the increase in female smoking and overweight. After menopause, the risks of myocardial infarction are equivalent for both sexes.
If a close relative (father, mother, brother or sister) has had a cardiovascular disease at an early age (stroke before age 45, myocardial infarction or sudden death of father or brother before age 55, mother or sister before age 65), the cardiovascular risk is increased.
Cardiovascular risk factors that can be acted upon
Tobacco promotes the narrowing of the arteries, the formation of clots and the appearance of heart rhythm disorders. In the long term, tobacco gradually damages the arteries.
The risk of myocardial infarction is proportional to tobacco consumption, but there is no consumption threshold below which smoking is risk-free.
The risk is the same regardless of the type of smoking: cigarettes with or without filter, pipe, cigar, hookah, chewing tobacco).
Passive smoking increases the risk of myocardial infarction by a quarter if the person is exposed for 1 to 7 hours per week and by 62% for exposure for 22 hours per week.
We speak of diabetes when the glycemia (sugar or glucose level in the blood) remains above 1.26 g/l on an empty stomach, during at least two measurements. If diabetes is poorly controlled, the excess glucose in your blood can damage the walls of the arteries.
High blood pressure
Blood pressure is the pressure exerted by blood on the walls of the arteries; it is expressed by two digits. We speak of high blood pressure if the upper number (systolic pressure) is greater than 140 mmHg or 14 cmHg and/or if the lower number (diastolic pressure) is greater than 90 mmHg or 9 cmHg.
A high cholesterol level
If cholesterol is essential for the proper functioning of the body, its excess is harmful to health. A distinction is made between bad cholesterol (LDL cholesterol) and good cholesterol (HDL cholesterol).
A blood test, carried out on an empty stomach, makes it possible to detect an excess of bad cholesterol.
In case of too fatty diet, overweight or obesity or in the absence of physical activity, bad cholesterol increases and accumulates on the walls of the arteries in the form of fatty deposits. Over time, these deposits can slow down and block blood circulation: this is atherosclerosis.
Overweight and obesity
We speak of being overweight if the body mass index (BMI) is greater than 25 and of obesity if it is greater than 30. The presence of abdominal fat is also a risk factor.
The waist circumference is considered too high, if it is greater than or equal to:
- 80 cm (31.5 in) for a woman.
- 94 cm (37 in) for a man.
Low physical activity or sedentary lifestyle
A sedentary lifestyle is defined by the practice of physical exercises lasting less than 30 minutes per day.
Drinking alcohol is not without risk. However, apart from situations where alcohol is totally inadvisable (pregnancy, driving, etc.), a benchmark value is recommended: it is 10 standard glasses of alcohol per week, maximum, without exceeding 2 standard glasses per day.
It is also recommended to have days in the week without consumption and, for each consumption occasion, to:
- Reduce the total amount of alcohol drunk on each occasion,
- Drink slowly, eating and alternating with water,
- Avoiding places and activities at risk of excessive alcohol consumption,
- Make sure you are surrounded by people you trust and that you can go home safely after consuming alcohol…