Management of Posterior MI
Clinical Presentation and Diagnosis
- Elderly women with posterior MI frequently present without classic chest pain, instead manifesting fatigue, dyspnea, faintness, or syncope, according to the European Society of Cardiology 1, 2
- The American College of Cardiology recommends obtaining additional posterior leads V7-V9 immediately for diagnosis of posterior MI, looking for ST elevation ≥0.05 mV 3
- On standard ECG, isolated ST-depression ≥0.05 mV in leads V1-V3 represents the dominant finding and should be treated as STEMI, as per the American Heart Association 3
Immediate Management
- The American College of Cardiology recommends administering morphine 4-8 mg IV with additional 2 mg doses at 5-15 minute intervals until pain is relieved, with an antiemetic (metoclopramide 5-10 mg IV) concurrently 4
- Aspirin 160-325 mg orally immediately is recommended by the American College of Cardiology, as well as sublingual nitroglycerin for ongoing chest pain 5, 6, 7
Reperfusion Strategy
- The American College of Cardiology recommends primary percutaneous coronary intervention within 120 minutes, which reduces mortality from 9% to 7%, with high-dose IV heparin during procedure 5, 6, 7
- If PCI cannot be achieved within 120 minutes, fibrinolytic therapy should be administered immediately, with the greatest benefit occurring within the first 6 hours of symptom onset 7
Medication Management
- The American College of Cardiology recommends IV beta-blocker (metoprolol 5 mg IV every 2 minutes for 3 doses) if no contraindications, monitoring BP and HR closely, as well as oral beta-blocker for at least 6 weeks 5, 6, 8
- Aspirin 160-325 mg daily indefinitely, as well as ACE inhibitor (lisinopril 5 mg initially, titrate to 10 mg daily) if hemodynamically stable, are recommended by the American College of Cardiology 5, 6, 9
Long-Term Management
- The American College of Cardiology recommends indefinite medical therapy with aspirin, beta-blocker, and ACE inhibitor, as well as target LDL <100 mg/dL with statin therapy 5, 8
- Lifestyle modifications, including smoking cessation, exercise (20 minutes of brisk walking at least 3 times weekly), and diet low in saturated fat and cholesterol, are essential for long-term management, as per the American Heart Association 5, 8