From: ClinicalPearl@...
Date: November 26, 2008 5:05:43 AM EST
To: glennskow@...
Subject: EMedHome Clinical Pearl

The New EMedHome Clinical Pearl is: Is A Right Ventricular Infarction Present?

Is A Right Ventricular Infarction Present?


Right ventricular infarction complicates approximately 25% inferior acute myocardial infarction. With RV infarction, the RV will fail and LV filling pressures are entirely dependent upon the patient's preload; with significant preload reduction, hypotension results (which may be worsened by nitroglycerin and morphine) (1). Therapy, in addition to appropriate management for STEMI, relies largely on enhancing the preload with IV fluid and judicious use of vasodilator medications. Patients with inferior wall STEMI with RV infarction have a markedly worse prognosis compared with patients with isolated inferior wall STEMI.

The standard 12-lead ECG does not image the RV to any significant extent. In the setting of inferior wall MI, if the degree of ST-segment elevation is disproportionately greater in lead III relative to the other inferior leads, RV infarction is suggested. ST-segment elevation in lead V1 (perhaps the only lead on the standard ECG that reflects changes occurring in the RV) is also suggestive of RV infarction.

Right-sided chest leads are much more sensitive and specific in detecting the changes of RV infarction. The clinician may use either the entire right-sided leads V1R through V6R or the single lead V4R. Lead V4R (right fifth intercostal space midclavicular line) is the most useful lead for detecting ST-segment elevation associated with RV infarction and may be used solely in the evaluation of the possible RV infarction (2).

Regardless of the ECG lead applied, the ST-segment elevation that occurs in association with RV infarction is frequently quite subtle, reflecting the relatively small muscle mass of the RV



Related Clinical Pearls of Interest:

• RV MI mimicking Anterior MI on EKG
   
• Unique Complication of RV Infarction
   

References:

(1) Moye S, et al.  The electrocardiogram in right ventricular myocardial infarction  Am J Emerg Med  2005;23(6):793-9.
(2) Somers MP, et al.   Additional electrocardiographic leads in the ED chest pain patient: right ventricular and posterior leads  Am J Emerg Med  2003;21(7):563–573.
 

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