[Right atrial thrombosis; an unusual late complication of the Fontan procedure. Apropos of a case]. / Thrombose de l'oreillette droite; complication tardive inhabituelle d'une intervention de Fontan. A propos d'un cas.

The authors report the case of a large right atrial thrombosis causing acute cardiac failure in an 18 year old patient with tricuspid atresia who had undergone 3 operations: Waterston shunt at 2 months of age, Fontan procedure at 3 years of age with reoperation at 13 years of age. The diagnosis was made at echocardiography and angiography. Surgical management comprised ablation of the thrombus and a tunneling of the right atrium between the inferior vena cava and the atriopulmonary conduit. The immediate postoperative course was complicated by a slowly regressive neurological deficit. The medium-term outcome (one year) is satisfactory with antiarrhythmic and anticoagulant therapy. A review of the literature showed that these thromboses are not exceptional in the early postoperative period for a variety of reasons. Secondary thrombosis is often related to arrhythmias, thus requiring clinical, electrocardiographic and echocardiographic follow-up of these patients and the prescription of antiarrhythmic and anticoagulant therapy. The diagnostic methods are discussed. Echocardiography may be sufficiently explicit to make potentially risky angiography unnecessary.