Heart attack

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 ensuing blood clot on background of coronary artery disease.

Symptoms

  • Chest pain radiating to neck, jaw, shoulder and back; the pain has a heavy, constricting or pressure-like character
  • Breathlessness
  • Strong anxiety and fear

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.

Treatment

Heart attack is an emergency requiring a prompt treatment. If there is any suspicion on heart attack, call immediately ambulance. 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) follow after several days.

Causes of MI

Coronary artery disease (CAD) is the main cause of 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 heart become narrow due to atherosclerotic plaques. The plaques may rupture and become 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 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.

Complications

    • Arrhythmias - ventricular fibrillation, when the heart is just fluttering without effective pumping; this leads to cardiac arrest and sudden death if not promptly treated with defibrillation (electric shock to ‘jump start’ the heart); atrial fibrillation, a type of irregular heart beat which requires anticoagulation to reduce risk of stroke
    • Cardiogenic shock - severe form of acute heart failure when damage to heart muscle is so extensive that heart is not able to pump enough blood into circulation
    • Mechanical complications – rupture of the heart walls or muscles related to heart valves leading to acute regurgitation (dysfunction of the valves which can cause heart failure)

These complications are the leading cause of death and appear usually in the first hours and days after the heart attack. Monitoring, prevention and prompt treatment of heart attack complications is one of the main tasks of coronary care units (CCU). In some cases, sudden death may occur before patient reaches the hospital.

Recovery

The duration and degree of recovery from heart attack is 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 fully 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 risk of another attack
- Restore physical fitness with cardiac rehabilitation and exercise

Prognosis

Most people not only survive heart attack but quickly return to normal life and if their risk factors are under control, the prognosis is excellent. The prognosis of heart attack depends on several factors:

- Time to the start of treatment – the shorter the better
- Type and severity of heart attack – 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 less favourable prognosis

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