A 58-year-old man presents to the emergency department with acute chest pain and is found to have the ECG pattern shown in the diagram marked as **B** (inferior STEMI with V4R ST elevation indicating RV infarction). On examination, he has a blood pressure of 88/56 mmHg, jugular venous distension with a paradoxical rise on inspiration, and clear lung fields on auscultation. Which of the following is the MOST appropriate initial management for this patient's hemodynamic instability?

Question

Accepted Answer

C. Aggressive intravenous normal saline bolus (1–2 L) titrated to clinical response and central venous pressure. ## Why aggressive IV normal saline is correct

Right ventricular infarction (marked as **B** in the diagram) complicates 30–50% of inferior STEMIs and results from proximal RCA occlusion before the RV marginal branches. The hallmark pathophysiology is RV failure with a noncompliant infarcted ventricle that cannot maintain adequate LV filling—making these patients exquisitely preload-dependent. The classic clinical triad (hypotension, JVD with Kussmaul sign, clear lungs) reflects this mechanism. Unlike LV failure, where reducing preload may be beneficial, RV infarction requires aggressive IV fluid resuscitation with normal saline (1–2 L bolus, titrated to CVP) as first-line therapy to restore RV preload and maintain LV filling and systemic perfusion. (Harrison's 21e, Braunwald's Heart Disease 12e, 2023 ACC/AHA STEMI Guidelines)

## Why each distractor is wrong

- **Intravenous nitroglycerin infusion**: Nitrates are CONTRAINDICATED in RV infarction because they reduce venous return and preload, causing dangerous hypotension in a preload-dependent ventricle. This is a classic pitfall that worsens hemodynamics.
- **Intravenous furosemide**: Diuretics are also contraindicated because they further reduce preload in an already preload-dependent RV, worsening hypotension and LV filling. JVD in RV infarction reflects inadequate RV output, not fluid overload.
- **Intravenous morphine followed by dobutamine**: While dobutamine may be used for inotropic support if hypotension persists despite fluids, morphine in large doses is avoided because it causes vasodilation and reduces preload. Fluids must be the first step; inotropes are second-line.

**High-Yield:** RV infarction = preload-dependent physiology → IV fluids first; AVOID nitrates, diuretics, and large-dose morphine (they cause collapse).

[cite: Harrison's 21e; Braunwald's Heart Disease 12e; 2023 ACC/AHA STEMI Guidelines]

Answer

A. Intravenous nitroglycerin infusion to reduce preload and afterload

Answer

B. Intravenous furosemide to reduce elevated jugular venous pressure

Answer

D. Intravenous morphine (10 mg) followed by dobutamine infusion

Explanation

Why aggressive IV normal saline is correct

Why each distractor is wrong

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