A 71-year-old man presents to the emergency department because of worsening shortness of breath and palpitations for the past 2 days. He reports increasing fatigue, orthopnea, and decreased exercise tolerance. He denies chest pain. His medical history is significant for ischemic cardiomyopathy with a left ventricular ejection fraction of 30%, hypertension, type 2 diabetes mellitus, and paroxysmal atrial fibrillation. Current medications include sacubitril-valsartan, metoprolol succinate, spironolactone, empagliflozin, furosemide, and apixaban. Temperature is 36.9°C (98.4°F), blood pressure is 118/72 mm Hg, pulse is 148/min and irregularly irregular, respiratory rate is 24/min, and oxygen saturation is 94% on room air. Physical examination reveals mild respiratory distress. Jugular venous pressure is elevated. Bibasilar crackles are present. There is 1+ bilateral lower-extremity edema.
Laboratory studies show the following:
ECG demonstrates atrial fibrillation with a ventricular rate of 150/min. No acute ischemic changes are present. Chest radiography reveals mild pulmonary vascular congestion.
Which of the following is the most appropriate next step in management?
The correct answer is:
B) Administer intravenous metoprolol
This patient has atrial fibrillation with rapid ventricular response (RVR) causing acute decompensated heart failure. Although he has signs of congestion, he remains hemodynamically stable because his blood pressure is preserved and there is no evidence of shock, ischemia, or severe end-organ dysfunction.
Rapid ventricular rates shorten diastolic filling time, reduce cardiac output, and increase myocardial oxygen demand. Patients with underlying HFrEF are particularly susceptible to decompensation because they rely heavily on adequate ventricular filling and rate control to maintain cardiac output.
In a hemodynamically stable patient with HFrEF and atrial fibrillation with RVR, rate control is the appropriate initial strategy. Intravenous beta blockers such as metoprolol are commonly used when blood pressure permits. Slowing the ventricular response improves diastolic filling and often leads to rapid symptomatic improvement.
A high-yield Step 2 principle is distinguishing stable from unstable atrial fibrillation. Patients who are hypotensive, ischemic, or in shock require immediate synchronized cardioversion. Stable patients should generally undergo rate control first.
Answer choice A: Administer intravenous diltiazem, is incorrect.
Diltiazem is often used for rate control in atrial fibrillation but is generally avoided in patients with HFrEF because of its negative inotropic effects. It may worsen systolic dysfunction and precipitate further heart failure decompensation.
Answer choice C: Immediate synchronized cardioversion, is incorrect.
Synchronized cardioversion is indicated for atrial fibrillation causing hemodynamic instability, such as severe hypotension, shock, ongoing ischemia, or altered mental status. Although this patient has symptomatic heart failure, he remains hemodynamically stable and should initially undergo pharmacologic rate control.
Answer choice D: Increase outpatient furosemide dosage and discharge home, is incorrect.
The patient’s decompensation is being driven by uncontrolled atrial fibrillation with RVR. Simply increasing diuretic therapy would fail to address the underlying problem. Furthermore, hospitalization is appropriate given his tachyarrhythmia and worsening heart failure symptoms.
Answer choice E: Initiate flecainide therapy, is incorrect.
Class IC antiarrhythmic agents such as flecainide are contraindicated in patients with structural heart disease, including ischemic cardiomyopathy. These medications increase the risk of serious ventricular arrhythmias in this population.
Key Learning Point
In patients with HFrEF, atrial fibrillation with rapid ventricular response commonly precipitates acute decompensation. Hemodynamically stable patients should undergo rate control, typically with a beta blocker, whereas unstable patients require immediate synchronized cardioversion.
