Acute Myocardial Infarction

✍️Acute Myocardial Infarction-
AMI is the acute death of myocardial cells due to lack of oxygenated blood flow in the coronary arteries. It is also known as a heart attack.


✍️Pathophysiology-
Injury to the artery’s endothelium →increases platelet adhesion →inflammatory response causing monocytes and T lymphocytes to migrate in the intima → macrophages and smooth muscle distend with lipids, forming fatty streaks and forming fibrous cap → thinning of cap increases susceptibility to rupture or hemorrhage → rupture triggers thrombus formation and vasoconstriction → result: thrombus with narrowing artery. If occlusion lasts more than 20 minutes it leads to AMI.


✍️Clinical Presentation
AMI presents with chest pain or discomfort lasting 20 minutes or longer. Pain can be described as pressure, tightness, heaviness, burning, or a squeezing or crushing sensation, located typically in the central chest or epigastrium; it may radiate to the arms, shoulders, neck, jaw, or back. 
Discomfort may be accompanied by weakness, dyspnea, diaphoresis, or anxiety, not relieved by NTG. Women may experience atypical discomfort, SOB, or fatigue. Diabetic patients may not display classic signs & symptoms of AMI. Elderly may experience SOB, pulmonary edema, dizziness, altered mental status.
 ST-segment elevation MI: Look for tall positive T waves and ST-segment elevation of 1 mm or more above baseline.
 Non-ST segment elevation MI: May include ST-segment depression and T-wave inversion.


✍️Diagnostic Tests

  • ECG findings
  • Cardiac markers (CK, myoglobin, and troponins)

 

✍️Management


 👉Focus on pain radiation, SOB, and diaphoresis.


👉Obtain a 12-lead ECG and lab draw for cardiac markers.


 👉 MONA: morphine, O2, NTG, and 160–325 mg aspirin, po. If allergic to aspirin, give ticlopidine (Ticlid) or clopidogrel (Plavix). 


👉Administer supplemental O2 to maintain SpO2 >90%.


👉 Administer SL NTG tablets or spray.


👉 Administer IV morphine 2–4 mg every 15 minutes until pain is controlled. (Monitor for hypotension and respiratory depression.)
 

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