Atrial Fibrillation Outpatient Presentation and Management

Case Presentation —A 68-year-old white man presents to the cardiology office complaining of mild fatigue. A new and first finding is an irregular pulse. Atrial fibrillation is confirmed on 12-lead ECG. He has no additional symptoms. Four months earlier, he had a drug-eluting stent placed for a discrete proximal left anterior descending artery lesion. Past history includes hypertension, hyperlipidemia, and non–insulin-dependent diabetes mellitus. The first step is to establish that the patient is hemodynamically stable and whether he needs inpatient evaluation for an associated condition. The patient has a normal blood pressure (125/80 mm Hg) and a well-controlled irregular heart rate (72 bpm) on atenolol 50 mg daily. There are no interval ECG changes apart from the atrial fibrillation suggestive of an acute process. On examination, he has a short 1/6 systolic murmur at the apex without radiation. He has no evidence of heart failure. Neurological examination is normal. Medications include atenolol 50 mg daily, lisinopril 5 mg daily, metformin, atorvastatin 20 mg daily, aspirin 325 mg daily, and clopidogrel 75 mg daily. Immediate hospitalization is not needed. Management goals are to rule out reversible causes of atrial fibrillation, maintain the heart rate at rest and with exercise in the physiological range, consider conversion to sinus rhythm, and determine which stroke prevention measures are needed. Reversible causes of atrial fibrillation are conveniently separated into cardiac and noncardiac causes. Noncardiac causes (electrolyte imbalance, thyrotoxicosis, fever from any cause [particularly pneumonia], pharmacological and recreational drug use, and alcohol use) were ruled out by history and physical and simple blood tests (thyroid function tests, serum electrolytes, and urine and serum toxicology). The cardiac causes of atrial fibrillation include any mechanism resulting in structural and functional changes to the heart. Transthoracic echocardiogram revealed moderate left ventricular hypertrophy but normal left ventricular systolic function, no …