USMLE Step 2 - Question 19

A 86 year old female with a history of diabetes mellitus and hypertension presents to the emergency room with a complaint of chest pain x 4 hours. She has noted severe nausea with 2 episodes of emesis as well. She is now chest pain free. Her blood pressure is 130/70, heart rate 50,  respirations 20, and oxygen saturation 95% on room air. Physical examination reveals normal breath sounds and an S4 heart sound without murmurs. Her ECG is below. Which of the following is the next appropriate step in management?

A. Sublingual nitroglycerine

B. Intravenous beta-blockers

C. Emergent cardiac catheterization

D. Glycoprotein IIb/IIIa inhibitor

Inferior-STEMI-4

The patient is having an acute inferior wall ST segment elevation myocardial infarction (inferior STEMI). Note the inferior (leads II, III, and aVF) ST segment elevation on the ECG with reciprocal ST depressions in leads I and aVL. This is the classic ECG appearance of an inferior STEMI. Also note the patient had significant nausea and vomiting which results from vagal hyperstimulation that occurs due to the proximity of the inferior wall and the diaphragm/vagus nerve. Emergency cardiac catheterization and stent implantation to restore coronary flow is crucial to patient outcomes. Currently it is recommended that the occluded vessel is re-opened withing 90 minutes of emergency room arrival. When there is no cardiac catheterization laboratory available, thrombolytic therapy is a good alternative. However, if the patient can be transferred to a nearby hospital with cardiac catheterization capabilities, this would be the correct course of action (as long as it can be done in < 90 minutes).

 

Since she is not having active chest pain there is no need for sublingual nitroglycerine which is given mainly for symptomatic relief (can also be used for hypertension). Also, along with the inferior STEMI there is a possibility that there is concomitant right ventricular infarction which results in severe hypotension with nitroglycerine administration due to the preload dependent state (remember that nitroglycerine reduces preload). Beta-blockers IV are contraindicated if the heart rate is < 60. A glycoprotein IIb/IIIa inhibitor is used as medical management of non-ST segment elevation myocardial infarctions or after stent implantation.