A heart attack or myocardial infarction (MI) is a life-threatening medical emergency with a sudden obstruction of the blood supply to the heart muscle. Heart attack is usually caused by a ruptured atherosclerotic plaque with an ensuing blood clot on the background of coronary artery disease.
The intensity of chest pain may vary, and in some people, especially in the elderly and in diabetic patients, the pain may not be present at all. Sometimes, the discomfort may resemble indigestion.
A heart attack is an emergency requiring prompt treatment. If there is any suspicion of a heart attack, call an ambulance immediately. If available and the affected person is not allergic, it is advisable to chew a tablet of Aspirin.
The definitive treatment aims to restore blood supply to the heart muscle and minimize the risk of recurrence. Patients with heart attack need a combination of medicines to achieve this, usually consisting of antiplatelets (aspirin, clopidogrel, prasugrel or ticagrelor), anticoagulation, beta-blocker and statin.
According to ECG (electrocardiogram), heart attacks are classified as STEMI (ST-elevation MI) or NSTEMI (non-ST elevation MI). Patients with STEMI are normally treated with immediate coronary angioplasty (primary PCI, PPCI), a catheter procedure in which the blocked coronary artery is opened and usually secured with a stent, a small metallic mesh. Patients with NSTEMI are usually first stabilized with medication, and coronary angiogram with subsequent angioplasty or less often bypass surgery (CABG) follows several days.
Coronary artery disease (CAD) is the main cause of the acute coronary syndrome, an umbrella term including heart attacks of STEMI and NSTEMI type and unstable angina. In CAD, coronary arteries that supply blood to the heart become narrow due to atherosclerotic plaques. The plaques may rupture and become the focus of sudden blood clot formation. The blood clot triggered by plaque rupture can completely block an artery and cut off blood supply to a part of the heart muscle, which leads to myocardial necrosis (irreversible damage to the heart muscle tissue) and scar.
The main risk factors for coronary artery disease are smoking, diabetes, hypertension (high blood pressure), hyperlipidaemia (high cholesterol), physical inactivity, obesity, age, positive family history and male gender.
These complications are the leading cause of death and usually appear in the first hours and days after the heart attack. Monitoring, prevention and prompt treatment of heart attack complications are among the main tasks of coronary care units (CCU). In some cases, sudden death may occur before the patient reaches the hospital.
The duration and degree of recovery from a heart attack are directly proportional to the amount of damage to the heart muscle. Some people may recover within two weeks enough to join routine activities, while others may need several months to get back to normal. The aim of rehabilitation following a heart attack is to:
- Implement lifestyle changes and healthy habits, learn to control risk factors
- Adjust and optimize medication to reduce the risk of another attack
- Restore physical fitness with cardiac rehabilitation and exercise
Most people not only survive a heart attack but quickly return to normal life, and if their risk factors are under control, the prognosis is excellent. The prognosis of a heart attack depends on several factors:
- Time to the start of treatment – the shorter, the better
- Type and severity of heart attack – the amount of damage to the heart muscle
- Any pre-existent damage to the heart muscle (presence of heart failure)
- Comorbidities (diabetes, kidney disease, lung disease and other medical problems)
- Age – as you would expect, advanced age and frailty carry a less favourable prognosis