The heart attack is the destruction of part of the heart muscle called myocardium . It occurs when, for example, a clot prevents the blood from circulating normally in the coronary artery, an artery that irrigates the heart. The latter is poorly irrigated and the heart muscle damaged.
Myocardial infarction, sometimes called a heart attack or acute coronary syndrome , is fatal in up to 10% of cases. As soon as the first symptoms appear, it is essential to prevent the rescue. First aid will be given in the ambulance and then hospitalization will be necessary. Then, long-term care will be offered, especially to prevent a new infarction or the appearance of cardiovascular complications. This post-infarction care will be composed of a drug treatment, a cardiovascular rehabilitation or changes of hygiene of life.
Myocardial infarction is caused by a clogged artery, which leads to poor oxygenation of the heart, and therefore to the destruction of part of the myocardium. Deprived of oxygen, the cells of this muscle die: we talk about necrosis . The myocardium contracts less well, a cardiac rhythm disorder appears and, if nothing is done, the heart stops beating. To avoid this fatal outcome, it is necessary to clear the artery as soon as possible.
But how can an artery are closed? The culprits are the atheroma plaques . Comprised mainly of cholesterol , these plaques can form at the level of the walls of the blood vessels, and therefore the coronary arteries, which irrigate the heart. If the atheroma plaque breaks and forms a clot, it can cause myocardial infarction.
The symptoms of myocardial infarction are quite characteristic: chest pain, shortness of breath, sweating, irregular heartbeat, discomfort in the hand or arm, etc.
Nevertheless, there are silent infarcts . The person suffering from it feels no symptoms. The silent infarction may go unnoticed but be discovered during an examination as an electrocardiogram. This silent infarction relates more generally to people who have diabetes.
Reminder : The heart is a pump that distributes blood to all organs. The myocardium is responsible for irrigating the body with blood and therefore oxygen.
In France there are about 100,000 myocardial infarctions a year. More than 5% of the people concerned would die in the next hour, almost 15% in the year that follows. This mortality rate has dropped significantly in 10 years, thanks in particular to the reactivity of the SAMU and the establishment of interventional cardiology services. The US figures speak of 8000.00 annual cases and 90 to 95% survival for hospitalized patients after myocardial infarction.
Diagnostic of Myocardial infarction
The symptoms of the infarct are usually very characteristic and allow the doctor to make a diagnosis very quickly. This diagnosis will be confirmed by different tests and exams like an electrocardiogram. The ECG will visualize the electrical activityheart and thus, to detect an anomaly. It will reveal if a heart attack has occurred or is occurring. A blood test will detect the presence of cardiac enzymes in the blood that reveal damage to part of the heart. A radio may be needed, especially to ensure that the lungs are not affected. Coronary angiography, which is used to visualize the coronary arteries, can also detect a decrease in the diameter of these arteries and the presence of an atheromatous plaque.
Causes of Myocardial infarction
The presence of atheroma plaque , composed mainly of cholesterol, may explain the appearance of a heart attack. This plaque can obstruct a coronary artery and prevent the heart from being irrigated properly.
A heart attack can also occur following a kind of spasm in a coronary artery. The blood flow is then interrupted. This spasm can be caused by a drug like cocaine. It can also appear following a tear in the artery of the heart or when the blood flow is greatly reduced, in case of very low blood pressure for example, what is called a hypovolemic shock.
Complications of Myocardial infarction
The complications of an infarct vary according to the extent of the area of the heart muscle affected by this infarction. The larger this area is, the more complications can be serious. The person may suffer from an arrhythmia , that is to say, heart rhythm disorders, heart failure or problems with one of the valves of the heart, which valve may have been damaged during surgery. ‘Attack. Infarction can also be complicated by a stroke. A new infarction can also occur.
The risk of complications will be evaluated by means of new examinations: ECG, ultrasound, coronarography, scintigraphy (to evaluate the functioning of the heart ) or a stress test. Drug treatment will also be prescribed.
Symptoms of Myocardial infarction
- Intense pain in the chest, feeling of tightening vise, crushing
- Pain that radiates into the left arm, the hand, which extends into the neck, jaw and back
- Cold sweats, moist skin
- Nausea, vomiting
- Abdominal pain
- Fast or irregular heartbeat
- Major and sudden anxiety
- Unusual tiredness
- Sleep disorder
- Loss of consciousness
An infraction can occur at any time. It can appear suddenly, but can also happen little by little, in a few days. In all cases it is imperative to call emergencies as soon as the first signs appear.
People at risk for of Myocardial infarction
The risk of having an infarct increases with age . The probability increases after 50 years for men, 60 for women. Women also have, before menopause, a lower risk of infarction compared to their male counterparts.
Family history is an important parameter in risk factors. Having a father or brother who has suffered an infraction increases his cardiovascular risk.
The risk factors for an infarct are diverse and varied. Some of these factors promote atherosclerosis and thus increase the risk of heart attack.
Thus, tobacco and alcohol can weaken the arteries. High blood pressure, an excess of bad cholesterol and diabetes, too. Lack of physical activity, overweight and obesity and stress are also risk factors for heart attack.
Prevention of infarction
The prevention of infarction involves the management of risk factors . To reduce the risk of heart attack, you must stop smoking and drink excessively. It may be important to change some of his bad habits for example to fight against overweight and high cholesterol (excess lipids in the blood).
Some medications such as aspirin may be prescribed as a preventative measure for people who are at high risk of having an infraction, as are statins to correct high cholesterol.
Medical treatment of infarction
The treatment of infarction must start as soon as possible, as soon as the ambulance arrives, which will take the sick person to an interventional cardiology unit.
Drugs can be administered to thin the blood and facilitate the irrigation of the heart . It can for example be aspirin or thrombolytic agents, which cause the destruction of the clot which blocks the artery. The faster the thrombolytic is administered, the better the chances of survival. The complications are also less serious.
At the hospital, angioplasty can be performed. Of antiplatelet agents (clopidogrel, aspirin, and prasugrel) can be prescribed to reduce the risk of formation of a new clot. Heparin, an anticoagulant for blood thinning, ACE inhibitors, used in high blood pressure and trinitrin (nitroglycerin) can also be given. Beta blockers can make heart work easier by slowing the heart rate and lowering blood pressure. The prescription of statins, cholesterol medications, can, if they are quickly administered, improve survival.
Pain medication such as morphine may be prescribed. Drug treatment, usually consisting of beta-blockers, platelet aggregation inhibitors, statins and angiotensin-converting enzyme inhibitors, is tailored to each patient and can evolve over time. In all cases, medication should be regular. The prescribed treatment must be followed correctly.
Surgically, angioplasty is performed. This is to unclog the clogged artery. For this, the doctor inserts a long, thin, flexible tube, a catheter, into the thigh and back to the heart. At the end of the catheter is a balloon that can be inflated. Thus, it crushes the clot and restores the blood circulation. A stent , a sort of spring, can then be placed. It allows the artery to remain open, at a normal diameter. A bypasscan also be realized. This is a surgical procedure that helps divert blood flow. It no longer passes through the portion of artery blocked by atherosclerosis but by another path. Thus, blood circulation in the heart is improved. Specifically, the surgeon places on both sides of the blocked area a blood vessel taken from another part of the body (usually at the level of the leg). Blood passes through this new “bridge”. If more than one area is obstructed, more than one bypass may be required.
After a myocardial infarction, examinations will make it possible to estimate the extent of the area of the damaged heart muscle, to detect a possible complication, such as heart failure, and to evaluate the risk of recurrence. At the end of his hospitalization, the person who suffered an infraction will be offered a cardiovascular rehabilitation . In the following year, she will have to go very regularly to her general practitioner and her cardiologist for a very close follow-up.