Heart attack (acute myocardial infarction) is one manifestation of coronary heart disease. When the flow of oxygen-rich blood supply to the heart suddenly slows down or becomes blocked, the heart can’t get enough oxygen and a local necrosis of cardiac tissue caused by insufficient supply of oxygen (hypoxia), starts to develop. This is what we call a heart attack.
Heart attack and its causes
The cause of heart attack is in more than 95% cases, closure of the coronary arteries (coronary arteries supplying the heart with oxygen) by blood clot – thrombus. Thrombosis often can lead to atherosclerotic narrowing in the coronary artery and cause an insufficient blood supply and necrosis of that part of the myocardium which receives blood from the artery. Closure of a coronary artery may be permanent, or at best only temporary. It is distressing for the body and can cause life-threatening arrhythmia, especially ventricular fibrillation or tachycardia.
Damaged heart muscle (myocardium) heal with a scar that to varying extents reduces the pumping function of the heart.
The Pre-stage of heart attack is hypo perfusion of the heart tissue – i.e. Myocardial ischemia. Whether it develops into a heart attack, i.e. ischemic necrosis, or the extent of dead heart tissue depends on many factors:
- the location and size of the closed artery,
- speed of closure,
- the overall state of the circulation in the organism
- the sensitivity of the tissue to ischemia.
During gradual restriction of blood supply to the vascular coupling (anastomosis) might be created which to some extent replace the supply to the affected area by neighboring arteries. Rapid closure of blood supply does not allow formation of these couplings.
If the person at the time of cardiac ischemia is at rest, tissue oxygen demands are small, infarct size and its consequences are minor and the patient has a higher chance of a full recovery.
During physical exertion, the tissue is damaged to a great extent. That is why it is so important when you have a chest pain to be calm to be at rest and not walking, stop driving, etc., and call an ambulance immediately.
What are symptoms of heart attack?
In some of the affected individuals, the heart attack can have no symptoms. Mostly, however, a heart attack has following typical symptoms:
- Searing, convulsive pressure or pain behind the breastbone (angina pectoris), which gradually spreads between the shoulders, the neck or left hand. This pain lasts longer than 20 minutes.
Objective symptoms are:
- Fast heart rate (tachycardia), or may be a slow heartbeat (bradycardia)
- Increased sweating
- Vomiting, nausea
Diagnostics of heart attack
Diagnosis is based on the ECG, typical biochemical changes in the blood and according to the above-described symptoms. The other diagnostic methods are echocardiography and selective coronary angiography.
Complications of heart attack
Heart attack may cause as already mentioned, arrhythmia, heart failure, cardiogenic shock, rupture of cardiac wall, pericarditis. These complications are a serious threat to the patient’s life.
What is the prevention of acute myocardial infarction?
Prevention is a long-term process focussing on a healthy lifestyle. This means not smoking, keeping your weight within normal limits, regular physical activity and healthy dining choices. People with hypertension, diabetes, obesity and high cholesterol levels, should concentrate and follow these restrictions.
Thrombophiliac diagnosed with congenital or acquired thrombophilia must emphasis on healthy lifestyle described above, beware of risks of hormonal contraception and know the risk situations for development of thrombosis, so that the overall thrombotic risk can be minimized.
Acute myocardial infarction is a life threatening condition and it is therefore important to ensure timely emergency medical help. If you experience symptoms of a heart attack, do not hesitate to call emergency services.