The Bottom Line: NTG and ECG

A patient walked into the triage area and reported chest pain, nausea, and "indigestion" for several hours. Initial vitals were stable. After a dose of nitroglycerin, the patient's "stable" vital signs had left the building. Though conscious, a repeat set of vitals (following the NTG dose) was as follows:
BP: 76/40
(Taken mutiple times on multiple extremities)
P: 72
Sp02: 89%
The hypotension resolved after a fluid bolus. An ECG finding (conveniently circled by an alert resident) reveals the answer to the hypotension story..

Right Sided 12 LEAD ECG

12 LEAD ECG INTERPREATION AND DISCUSSION

A baseline sinus rhythm is present. ST segment elevations are seen in the inferior wall leads II, III, and aVF. Expected reciprocal changes in the form of ST segment depressions are seen in leads I and aVL. The right sided chest lead V4 (V4R)  shows ST elevation. STE in V4R indicates right ventricular infarction. These patients are preload dependent. Nitroglycerin is a potent vasodilator. When this drug is administered in the setting of a right ventricular infarction, it can cause significant hypotension. The precipitous drop in blood pressure usually resolved after a fluid bolus.

PEARLS

• Initiate IV access prior to nitroglycerin administration in patients with inferior wall changes
• Look for right ventricular myocardial infarction by obtaining right sided chest leads
• Right ventricuar infarction usually co-exists with inferior wall ischemia
• STE in II, III, aVF ? Start an IV and reassess folliwing NTG administration!