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Difficulty: MediumPharmacologic Interventions

A 72-year-old man is evaluated in the emergency department for worsening shortness of breath, orthopnea, and lower extremity swelling over the past week. He has a history of ischemic cardiomyopathy with a left ventricular ejection fraction of 30%30\%. Blood pressure is 112/72112/72 mmHg, heart rate is 138138/min, and respiratory rate is 2222/min. Oxygen saturation is 92%92\% on room air. Cardiac examination reveals an irregularly irregular rhythm and a third heart sound (S3S_3). Pulmonary examination shows bibasilar crackles extending midway up the lung fields. Bilateral 2+2+ lower extremity pitting edema is present. Electrocardiogram demonstrates atrial fibrillation with a rapid ventricular response. Intravenous furosemide is administered. Which of the following is the most appropriate additional pharmacologic intervention?

  1. Intravenous digoxinAnswer
  2. B
    Intravenous diltiazem
  3. C
    Intravenous metoprolol tartrate
  4. D
    Intravenous heparin
  5. E
    Oral flecainide

Answer

Intravenous digoxin is the most appropriate intervention to control the patient's heart rate without worsening his acute heart failure.
The correct answer is intravenous digoxin. This patient is presenting with acute decompensated heart failure (ADHF) with a reduced left ventricular ejection fraction (HFrEF) of 30%30\%. His decompensation is exacerbated by atrial fibrillation with a rapid ventricular response. The immediate goals of therapy are to relieve pulmonary congestion (via loop diuretics like furosemide) and control the ventricular rate to improve diastolic filling time. In patients with severe HFrEF who are acutely decompensated, standard rate-controlling agents such as beta-blockers and non-dihydropyridine calcium channel blockers are contraindicated due to their negative inotropic effects. Intravenous digoxin (or intravenous amiodarone) are the preferred agents for acute rate control in this specific setting because they effectively lower the heart rate without significantly depressing left ventricular contractility.

Step-by-Step Solution

1
Identify the patient's primary acute physiologic derangement.
The patient is presenting with acute decompensated heart failure (ADHF) characterized by pulmonary edema and an S3S_3 gallop, exacerbated by atrial fibrillation with a rapid ventricular response.
Establishing the clinical state is required to recognize which therapies are safe and which are strictly contraindicated.
2
Determine the immediate therapeutic goals in the emergency department.
The acute goals are to relieve pulmonary congestion (initiated with furosemide) and control the rapid ventricular rate to improve diastolic filling time and cardiac output.
Rapid heart rates significantly reduce diastolic filling time, which acutely worsens pulmonary congestion and limits forward flow in patients with severe HFrEF.
3
Select a rate-controlling agent that lacks negative inotropic effects.
Intravenous digoxin (or amiodarone) is selected because it achieves rate control via vagal stimulation at the atrioventricular node without depressing myocardial contractility.
Standard first-line rate control agents (beta-blockers and non-dihydropyridine calcium channel blockers) possess strong negative inotropic properties and can cause catastrophic hemodynamic collapse in the setting of ADHF.

Key Concept

Management of atrial fibrillation with rapid ventricular response in the setting of acute decompensated heart failure with reduced ejection fraction.

Alternative Method

Intravenous amiodarone could also be utilized in this setting. Like digoxin, amiodarone provides effective rate control without significant negative inotropic effects, making it a safe and frequently used alternative for patients with acute decompensated heart failure.
Estimated Time:1m 30s
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Pharmacologic Interventions

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