A 34-year-old man comes to the emergency department with palpitations for the past 4 hours. He has no associated chest pain, shortness of breath, or dizziness. His medical history is significant for Wolff-Parkinson-White syndrome with 3 prior episodes of supraventricular tachycardia. The patient does not use tobacco or illicit drugs and drinks alcohol only on social occasions. He had 5 cans of beer at a party the previous night. On examination, his blood pressure is 120/80 mm Hg and pulse is irregularly irregular. ECG shows atrial fibrillation with a rate of 160/min. What is the best next step in management of this patient?

Question

A 34-year-old man comes to the emergency department with palpitations for the past 4 hours.  He has no associated chest pain, shortness of breath, or dizziness.  His medical history is significant for Wolff-Parkinson-White syndrome with 3 prior episodes of supraventricular tachycardia.  The patient does not use tobacco or illicit drugs and drinks alcohol only on social occasions.  He had 5 cans of beer at a party the previous night.  On examination, his blood pressure is 120/80 mm Hg and pulse is irregularly irregular.  ECG shows atrial fibrillation with a rate of 160/min.  What is the best next step in management of this patient?

Quizplus · Accepted Answer

Explanation: In Wolff-Parkinson-White syndrome (WPW), an accessory pathway conducts depolarization directly from the atria to the ventricles without traversing the atrioventricular (AV) node. Atrial fibrillation (AF) occurs in 10%-30% of individuals with WPW, and is a potentially life-threatening emergency; AF in WPW can bypass the usual rate-limiting function of the AV node, leading to very rapid ventricular response rates. Persistent AF with rapid ventricular response in patients with WPW can ultimately deteriorate into ventricular fibrillation (VF). Acute treatment of AF in patients with WPW is aimed at prompt control of ventricular response and termination of AF as follows: Hemodynamically unstable patients require immediate electrical cardioversion For stable patients, rhythm control with anti-arrhythmic drugs such as intravenous ibutilide or procainamide is preferred (Choices A, B and E) AV nodal blocking agents such as adenosine, beta blockers, calcium channel blockers (especially verapamil), and digoxin should not be used for AF in patients with WPW as they may promote conduction across the accessory pathway and lead to degeneration of AF into VF. (Choice C) Lidocaine is used for ventricular arrhythmias and is not indicated for AF. Educational objective: Patients with Wolff-Parkinson-White syndrome who develop atrial fibrillation with a rapid ventricular rate should be treated with cardioversion or antiarrhythmics such as procainamide. Atrioventricular nodal blockers such as beta blockers, calcium channel blockers, digoxin, and adenosine should be avoided as they can cause increased conduction through the accessory pathway. References: 2014 AHA/ACC/HRS guideline for the management of patients with atrial fibrillation: executive summary: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines and the Heart Rhythm Society. (http://www.ncbi.nlm.nih.gov/pubmed/24682348)

A 34-Year-Old Man Comes to the Emergency Department with Palpitations