A 36-year-old man comes to the emergency department due to a sudden onset of chest fluttering, dizziness, and weakness that started after breakfast an hour ago. He has had no chest pain or shortness of breath. The patient had a similar episode a month ago that woke him up from sleep, after which he went to the emergency department and was diagnosed with atrial fibrillation. The episode terminated spontaneously, and he was discharged with metoprolol and low-dose aspirin. Since then, the patient had been feeling well until today's symptoms began. Medical history is otherwise insignificant, and he has no family history of heart disease. The patient jogs 2 miles daily and tries to eat "healthy." He used to drink beer on the weekends, but he has abstained from alcohol for the past month. He is a lifelong nonsmoker.
Blood pressure is 118/67 mm Hg and pulse is 144/min and irregular. BMI is 26 kg/m². The lungs are clear to auscultation.
ECG shows atrial fibrillation with rapid ventricular response. Transthoracic echocardiogram shows normal left ventricular size and function. Complete blood count and metabolic panel are unremarkable. TSH is 2.5 µU/mL.
After initial evaluation, electrical cardioversion is performed, which successfully restores normal sinus rhythm.
Which of the following is the best next step in management of this patient?

Question

Quizplus · Accepted Answer

11ec193a_95cd_e9c5_853d_c3160d6028be_MD0002_00 Paroxysmal atrial fibrillation (PAF) is defined as >2 episodes of atrial fibrillation that terminate spontaneously or with intervention (eg, cardioversion) in <7 days. The majority of patients with PAF will continue to have recurrent episodes, ranging from 70% at 1 year to approximately 90% at 4 years. Patients with frequent, symptomatic episodes should be offered antiarrhythmic therapy to reduce recurrent episodes and help maintain sinus rhythm; however, selection of an appropriate antiarrhythmic agent requires consideration of the specific clinical setting. This patient is young and healthy, without any comorbid conditions, and his echocardiogram reveals no structural abnormalities. In such patients, flecainide or propafenone (class 1C antiarrhythmics) are the preferred antiarrhythmic agents due to their efficacy and favorable adverse effect profile. Importantly, these drugs are contraindicated in patients with coronary artery disease (CAD) or structural heart disease (eg, left ventricular hypertrophy, valvular heart disease, cardiomyopathy) due to an increased risk of ventricular arrhythmia and death in these settings. (Choice A) As flecainide and propafenone are contraindicated in patients with CAD, stress testing with or without coronary angiography is appropriate in some patients prior to initiation of these drugs. However, clinically significant CAD is extremely unlikely in this young patient without risk factors or symptoms suggestive of the disease, and evaluation for CAD is not indicated. (Choice B) Amiodarone has been shown to be more effective in maintaining sinus rhythm than flecainide, propafenone, or sotalol. However, the drug can cause significant systemic toxicity (eg, pulmonary, ophthalmic, thyroidal, hepatic) with long-term use and therefore is not recommended for this young patient. (Choice C) Digoxin can be useful for heart rate control in patients with atrial fibrillation with rapid ventricular response, particularly in the setting of heart failure. However, it does not have significant rhythm control properties and is not used for preventing recurrences in patients with PAF. (Choice E) Transesophageal echocardiogram (TEE) is used to confirm the absence of left atrial thrombus prior to chemical or electrical cardioversion in atrial fibrillation of >48 hours or unknown duration. However, this patient with onset of atrial fibrillation <48 hours ago does not require TEE before or after cardioversion. Educational objective: Flecainide and propafenone are class 1C antiarrhythmic agents with good efficacy and a favorable adverse effect profile. In the absence of ischemic or structural heart disease, they are the preferred agents to reduce the frequency and duration of episodes in patients with symptomatic paroxysmal atrial fibrillation. __________ References: Outpatient treatment of recent-onset atrial fibrillation with the "pill-in-the-pocket" approach. (http://www.ncbi.nlm.nih.gov/pubmed/15575054)

A 36-Year-Old Man Comes to the Emergency Department Due to a Sudden