A 58-year-old man with hypertension and 30 pack-year smoking history presents to the ED with crushing substernal chest pain for 90 minutes, diaphoresis, and nausea. On examination: BP 88/52, HR 50, JVP elevated 8 cm above sternal angle, lungs clear bilaterally, no murmur. A 12-lead ECG shows sinus bradycardia with ST elevation in II, III, aVF and ST depression in V1–V3. Right-sided lead ECG shows ST elevation ≥1 mm in V4R. The ECG pattern marked **A** in the diagram indicates inferior STEMI with right ventricular infarction. Which of the following medications should be AVOIDED in the acute management of this patient?

Question

Accepted Answer

A. Glyceryl trinitrate (GTN) sublingual. ## Why Glyceryl trinitrate (GTN) sublingual is right

The pattern marked **A** — inferior STEMI with ST elevation in V4R — indicates right ventricular infarction. RV infarction is preload-dependent; the infarcted RV relies on adequate venous return to generate sufficient contractility to push blood into the LV. Nitrates cause systemic and venous vasodilation, reducing preload. In RV infarction, this precipitates catastrophic hypotension and cardiogenic shock. ESC STEMI Guidelines 2023 explicitly recommend AVOIDING nitrates, morphine, diuretics, and beta-blockers in RV infarction. The clinical triad of hypotension + clear lung fields + elevated JVP is pathognomonic for RV involvement and mandates preload-preserving therapy.

## Why each distractor is wrong

- **Intravenous normal saline bolus (500–1000 mL)**: This is the FIRST-LINE treatment for hypotension in RV infarction. Fluid boluses restore preload and improve RV contractility, directly addressing the hemodynamic derangement.
- **Aspirin 325 mg and ticagrelor loading**: Dual antiplatelet therapy is initiated immediately in all STEMI patients, including those with RV involvement. These agents prevent stent thrombosis and are essential for reperfusion strategy.
- **Unfractionated heparin bolus before PCI**: Anticoagulation with UFH or bivalirudin is given before and during PCI in all STEMI patients. It is not contraindicated in RV infarction and is necessary for thromboprophylaxis.

**High-Yield:** RV infarction = preload-dependent physiology; avoid all preload-reducing agents (nitrates, morphine, diuretics); give IV fluids first, then inotropes if needed.

[cite: ESC STEMI Guidelines 2023; Inferior STEMI with RV involvement management]

Answer

B. Intravenous normal saline bolus (500–1000 mL)

Answer

C. Aspirin 325 mg and ticagrelor loading

Answer

D. Unfractionated heparin bolus before PCI

Explanation

Why Glyceryl trinitrate (GTN) sublingual is right

Why each distractor is wrong

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