Atrial fibrillation is a commonly encountered clinical problem. Although a large percentage of patients have no dearly identifiable precipitant, secondary atrial fibrillation is a well-documented clinical entity.'

Case presentation

A 73-year-old female with a history of obstructive sleep apnea, hypertension, and chronic obstructive pulmonary disease presents with complaints of intermittent palpitations, substernal squeezing chest pressure, and shortness ofbreath for two weeks. Her most recent episode occurred on the bus, prompting her to come to the emergency room for evaluation. Further questioning revealed mild weight loss and diarrhea over the prior few weeks. Home medications included amlodipine, baby aspirin, albuterol as needed, and ciprofloxacin for a recently diagnosed URI.