Identification and localization of STEMI: INFERIOR WALL

I.                 Recognizing the Inferior Wall MI



Courtesy of Dr. Amal Mattu (ECG's for the Emergency Physician)

ST segment elevation is observed in the inferior leads, or leads II, III, and aVF. There is reciprocal ST segment depression in the lateral leads or leads I and aVL. Remember to use caution in when treating inferior wall MI’s with nitroglycerin. A certain percentage of these infarctions can involve the right ventricle. If the right ventricle is injured, patients are at risk for profound hypotension following nitroglycerin! An alert provider will always establish IV access prior to administering NTG in patients like this. You can diagnose a right ventricular wall infarction by placing the V4 lead on the patient’s right chest. ST elevation in V4 (R ) confirms the diagnosis of right ventricular myocardial infarction. The most important part of this ECG is the recognition of ST segment elevation in the inferior leads.


KEY POINTS: 

• Inferior wall STEMI shows STE in leads II, III, aVF
• Reciprocal changes are seen in leads I and aVL