Heart Attack (Myocardial Infarction): Symptoms, First Aid, and Treatment

A heart attack (myocardial infarction) is damage to the heart muscle from lack of oxygen following blockage of the coronary arteries. This guide comprehensively covers the pathophysiology of heart attack, typical and atypical symptoms, first-aid steps, modern treatment, risk factors, and prevention strategies.

Plaque formation: over the years, plaques made up of cholesterol, calcium, inflammatory cells, and fibrous tissue build up in the inner layer (intima) of the coronary artery wall. This process usually progresses silently for decades.
Plaque rupture: an apparently stable atherosclerotic plaque can suddenly tear (rupture). Inflammation, physical stress, blood-pressure changes, and weakness in the plaque structure all play a role in rupture.
Thrombus formation: platelets accumulate on the surface of the ruptured plaque, the coagulation cascade is activated, and a thrombus (blood clot) forms. This clot partially or completely occludes the coronary artery.
Ischemia and necrosis: the region of heart muscle supplied by the occluded artery becomes deprived of oxygen (ischemia). If blood flow is not restored within 20–30 minutes, the heart muscle cells begin to die irreversibly. The longer the blockage lasts, the greater the damage.

STEMI (ST-Segment Elevation MI): caused by complete occlusion of the coronary artery. Characteristic ST-segment elevation is seen on the ECG. Damage involves the full thickness of the heart wall (transmural). Emergency reperfusion therapy (angioplasty or a clot-busting drug) is required. It is the most dangerous type of MI, and minutes can save lives.
NSTEMI (Non-ST-Segment Elevation MI): caused by partial occlusion of the coronary artery or by a transient complete occlusion. The ECG shows ST depression or T-wave changes but no ST elevation. Diagnosis is based on a rise in troponin. While not as immediately urgent, invasive evaluation is usually performed within 24–72 hours.

Chest pain or pressure: the most common and most important symptom. A squeezing, pressing, crushing pain is felt in the center or left side of the chest. Patients often describe it as "like an elephant sitting on my chest" or "a fist clenching in my chest." The pain typically lasts more than 20 minutes and does not fully resolve with rest or nitroglycerin.
Radiation of pain: chest pain may radiate to the left arm (most often), both arms, jaw, neck, back, or upper abdomen.
Sweating (diaphoresis): cold, clammy sweating is a very important sign of a heart attack. It is caused by sympathetic nervous system activation.
Nausea and vomiting: especially common in inferior (lower-wall) MI. It is caused by vagal stimulation.
Shortness of breath (dyspnea): develops because of reduced heart pumping power and fluid buildup in the lungs.
Dizziness and feeling of fainting: related to decreased cardiac output.
Intense anxiety: a fear of death or a sense that something is very wrong (angor animi).

In women: heart attacks more often present with atypical symptoms compared with men. Instead of chest pain, severe fatigue, shortness of breath, upper back pain, jaw pain, nausea, a sense of indigestion, and sleep disturbance may dominate. This can lead to delayed diagnosis in women.
In diabetic patients: pain perception may be impaired due to diabetic neuropathy. The so-called "silent MI" — a heart attack without clear chest pain — is more common in diabetics. Unexplained weakness, shortness of breath, or sudden poor blood-sugar control may be the only finding.
In the elderly: in people over 75, instead of chest pain, confusion (altered mental status), sudden decline, shortness of breath, or syncope (fainting) may be the presenting feature.

Dual antiplatelet therapy: aspirin + a P2Y12 inhibitor (clopidogrel, ticagrelor, or prasugrel) for at least 12 months
Beta-blockers: reduce heart rate and oxygen consumption, lower arrhythmia risk
ACE inhibitors / ARBs: prevent cardiac remodeling
Statins: high-dose statin therapy lowers LDL cholesterol and stabilizes plaque
Anticoagulant: heparin administration in hospital

Age: risk increases in men over 45 and in women over 55 (after menopause)
Sex: more common at earlier ages in men; however, after menopause risk rises rapidly in women
Family history: a first-degree male relative with coronary artery disease before age 55, or a female relative before age 65, increases risk

Smoking: the strongest preventable risk factor for coronary artery disease. It accelerates atherosclerosis through endothelial damage, oxidative stress, and prothrombotic effects. Quitting smoking halves the risk within a year.
Hypertension: high blood pressure accelerates atherosclerosis by causing mechanical damage to the artery wall. Target blood pressure is generally below 130/80 mmHg.
Dyslipidemia: high LDL cholesterol, low HDL cholesterol, and high triglycerides promote plaque formation.
Diabetes mellitus: both type 1 and type 2 diabetes increase cardiovascular risk 2–4 fold. Diabetic patients are also at risk for silent MI.
Obesity: especially abdominal obesity (waist circumference >102 cm in men, >88 cm in women) raises risk through insulin resistance, inflammation, and metabolic syndrome.
Physical inactivity: a sedentary lifestyle is an independent risk factor that contributes to many other risk factors.
Stress: chronic stress and acute emotional stress can trigger coronary events.
Diet: a diet rich in saturated fats, processed foods, and salt, and poor in vegetables and fruit, raises risk.

Quit smoking: the single most effective intervention. Professional support and pharmacotherapy raise success rates.
Exercise regularly: at least 150 minutes per week of moderate-intensity aerobic exercise (brisk walking, cycling, swimming) is recommended.
Eat healthily: the Mediterranean diet has the strongest evidence base for heart health. Aim for a diet rich in vegetables, fruits, whole grains, legumes, olive oil, fish, and nuts; low in red meat, processed foods, salt, and sugar.
Keep your blood pressure under control: measure regularly and adhere to medication if needed.
Monitor your cholesterol levels: keep LDL cholesterol below target. In high-risk patients the LDL target is below 55 mg/dL.
Diabetes management: achieve your HbA1c target and follow regular check-ups.
Maintain a healthy weight: keep body mass index between 18.5–24.9 kg/m².
Manage stress: use meditation, deep-breathing exercises, hobbies, and social support.

Supervised exercise training: a progressively increasing exercise program with the cardiologist's approval and a physiotherapist's supervision
Nutritional counseling: building a heart-friendly eating plan
Psychological support: depression and anxiety are common after MI; psychological support speeds recovery
Risk-factor education: training on smoking cessation, stress management, and medication adherence
Return-to-work planning: planning a safe return to work and daily activities

Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine, 12th Edition
Harrison's Principles of Internal Medicine, 22nd Edition — Chapters: Ischemic Heart Disease, ST-Segment Elevation Myocardial Infarction
Tintinalli's Emergency Medicine: A Comprehensive Study Guide, 9th Edition
ACC/AHA 2013 Guidelines for the Management of ST-Elevation Myocardial Infarction
ESC 2023 Guidelines for the Management of Acute Coronary Syndromes

Heart Attack (Myocardial Infarction): Symptoms, First Aid, and Treatment

Dr. Emre Gecer

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