Myocardial Infarction (Heart Attack)

• Myocardial infarction (MI), or heart attack, occurs when blood flow to a part of the heart is blocked for a long enough time to cause damage or death of the heart muscle.

Types

1. ST-Segment Elevation Myocardial Infarction (STEMI):

   • Severity: Severe type where a major coronary artery is completely blocked.
   • ECG Changes: ST-segment elevation on the electrocardiogram.

2. Non-ST-Segment Elevation Myocardial Infarction (NSTEMI):

   • Severity: Less severe; artery is partially blocked.
   • ECG Changes: No ST-segment elevation but may show other signs of heart damage.

Etiology

• Atherosclerosis: Rupture of an atherosclerotic plaque and subsequent blood clot formation.
• Coronary Artery Spasm: Severe spasm reducing blood flow to the heart.

Pathogenesis of Myocardial Infarction

1. Plaque Rupture: Atherosclerotic plaque in a coronary artery ruptures.
2. Thrombus Formation: A blood clot forms at the rupture site, completely blocking blood flow.
3. Ischemia and Necrosis: Lack of oxygenated blood leads to death of heart muscle tissue (infarction).

Signs and Symptoms

• Chest Pain: Intense, persistent pain or pressure.
• Radiating Pain: Pain may extend to arms, neck, jaw, or back.
• Shortness of Breath: Due to impaired oxygen delivery.
• Other Symptoms: Sweating, nausea, vomiting, light-headedness, fatigue.

Management and Treatment

1. Emergency Treatment

   • Immediate medical attention.
   • Oxygen therapy.
   • Pain relief (e.g., morphine).
   • Nitroglycerin administration.

2. Medications

   • Thrombolytics: Dissolve blood clots.
   • Antiplatelet Agents: Aspirin, clopidogrel.
   • Beta-blockers: Reduce heart workload.
   • ACE Inhibitors: Lower blood pressure.
   • Statins: Lower cholesterol levels.

3. Medical Procedures

   • Percutaneous Coronary Intervention (PCI): Angioplasty and stenting to open blocked arteries.
   • Coronary Artery Bypass Grafting (CABG): Surgery to bypass blocked arteries.

Thank you for reading from Firsthope's notes, don't forget to check YouTube videos!