The transthoracic application of synchronized direct current cardioversion (DCC) is widely used to terminate atrial fibrillation, atrial flutter, and other supraventricular tachyarrhythmia. DCC is a highly effective method for acute restoration of sinus rhythm. Although DCC is a relatively safe and frequently performed procedure, data on potential side effects are very rarely reported in the literature. The most serious com plications associated with DCC are thromboembolism and intracranial hemorrhage. The true incidence of postcardioversion pulmonary edema is not known, but it is esti mated to occur in 1% to 3% of patients, particularly those with coexistent heart dis ease. We report on a patient with a structurally normal heart who developed acute pulmonary edema after undergoing DCC. The patient had no evidence of myocardial injury according to an electrocardiogram and cardiac biomarkers. The patient was treated with intravenous diuretics. After 4 days, the pulmonary edema resolved.