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Difficulty: HardInitial Stabilization and Triage

A 58-year-old man is brought to the emergency department by emergency medical services due to severe, crushing substernal chest pain that began one hour ago while he was resting. The pain radiates to his left jaw and is associated with profound dizziness and diaphoresis. His medical history is significant for hypertension and type 2 diabetes mellitus. On arrival, he appears ashen and lethargic. Vital signs show a temperature of 36.6°C (97.9°F), blood pressure of 74/42 mmHg, heart rate of 112/min, respiratory rate of 20/min, and oxygen saturation of 95% on ambient air. Physical examination demonstrates prominent jugular venous distension, but pulmonary auscultation reveals clear lung fields bilaterally without crackles or wheezes. A rapid 12-lead electrocardiogram demonstrates 3-mm ST-segment elevations in leads II, III, and aVF, with reciprocal ST-segment depressions in leads I and aVL. Which of the following is the most appropriate initial step in the management of this patient?

  1. Administration of a rapid intravenous isotonic crystalloid bolusAnswer
  2. B
    Administration of sublingual nitroglycerin
  3. C
    Urgent consultation with interventional cardiology for percutaneous coronary intervention
  4. D
    Obtaining a right-sided electrocardiogram
  5. E
    Computed tomography angiography of the chest

Answer

The correct answer is the administration of a rapid intravenous isotonic crystalloid bolus to optimize right ventricular preload.
The patient's presentation of an inferior ST-elevation myocardial infarction (leads II, III, aVF) combined with profound hypotension, jugular venous distension, and clear lungs is highly specific for a right ventricular infarction. Because the ischemic right ventricle functions primarily as a passive conduit, it is highly dependent on adequate preload to push blood into the pulmonary circulation and subsequently fill the left ventricle. When profound hypotension is present, the immediate stabilizing intervention is to maximize right ventricular preload by administering a rapid intravenous isotonic crystalloid bolus.

Step-by-Step Solution

1
Analyze the clinical presentation and vital signs.
The patient is in cardiogenic shock (blood pressure 74/42 mmHg) with elevated jugular venous pressure but clear lung fields.
Identifying the triad of hypotension, elevated jugular venous pressure, and clear lungs is critical for diagnosing right ventricular failure.
2
Correlate the physical findings with the electrocardiogram results.
ST-segment elevations in inferior leads (II, III, aVF) suggest an inferior myocardial infarction, which involves the right ventricle in up to 50% of cases.
Inferior STEMIs are typically caused by right coronary artery occlusion, which also supplies the right ventricle.
3
Determine the physiological requirements for stabilization.
The ischemic right ventricle loses contractility and becomes highly dependent on venous return (preload) to pump blood to the left side of the heart.
Without adequate preload, left ventricular filling plummets, causing profound systemic hypotension.
4
Select the immediate intervention that addresses the hemodynamic instability.
Isotonic crystalloid boluses are required to increase right-sided filling pressures.
Hemodynamic stabilization (ABCs) must be initiated prior to confirmatory diagnostics (like a right-sided ECG) or definitive transfer (to the catheterization laboratory).

Key Concept

Patients with right ventricular myocardial infarction (inferior STEMI, clear lungs, hypotension, jugular venous distension) are highly preload-dependent; immediate stabilization requires intravenous crystalloid boluses to maintain cardiac output, and preload-reducing agents (nitrates, diuretics) must be avoided.
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Topics

Initial Stabilization and Triage

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