We present the case of an unusual complication after percutaneous closure of a giant coronary artery fis-tula. A 76-year-old man with previous admissions due to right heart failure and previous history of atrial fibrillation under acenocumarol, was admitted to our hospital for new onset of symptoms, characterized by progressive dyspnoea and peripheral edema. Physical examination revealed signs of congestive heart failure and a continuous murmur loudest along the lower sternal border. X-Ray showed cardiomegaly due to right chambers dilatation. Transthoracic echocardiography showed right chambers pressure and volume overload, with right ventricular enlargement and dysfunction, tricuspid annulus dilatation and severe tricuspid regurgitation. Cardiac catheterization showed significant elevation of right atrial pressure, as well as significant step-up of oxygen saturation in this chamber. Coronary angiography revealed the presence of a large fistula between the circumflex coronary artery (CCA) and coronary sinus (CS), with severe dilation of the CCA (maximum diameter20 mm). An Amplatzer? PDA was implanted in a distal elbow of the fistula with initailly good results. Anticoagulant therapy was then reinitiated, and a few days later, the patient developed clinical worsening of heart failure and dyspnoea. Echocardiogram showed significant pericardial effusion. Pleuropericardial window was then made draining a500 cm3 of bloody pericardial effusion. The postoperative outcome was excellent, with symptomatic relief and no signs of heart failure.