Hydatid cyst of the interventricular septum causing complete heart block and postoperative ventricular septal defect

Cardiac involvement is seen in 0.5-2% of patients with hydatid disease, and involvement of the interventricular septum (IVS) is even rarer. We report surgical treatment of a large cardiac hydatid cyst in the IVS. A 55-year-old woman presented with dyspnea and bradycardia. Transthoracic echocardiography revealed a large cyst in the mid to apical part of the IVS. The patient was placed on cardiopulmonary bypass. Through an incision to bulging part of cyst into right atrium, and without opening adjacent cardiac chambers, we aspirated the entire contents of the cyst, removed its germinative membrane, and washed the cavity with 96% alcoholic solution. The patient recovered uneventfully. She had begun taking albendazole 5 days preoperatively, and this therapy was continued for 12 weeks postoperatively. A permanent pace maker was implanted because she was dependent on temporary pace maker and after 1 year follow-up, complete heart block had not recovered to normal conduction rhythm.