[Syncope with a rare etiology, cardiac hydatidosis]

A case of left ventricular hydatid disease causing mitral insufficiency and revealed by accelerated idioventricular rhythm (AIVR) is reported. The traditional and more recent diagnostic procedures including echocardiography and immunology are reviewed. The persistence of AIVR and mitral insufficiency after excision of the cyst are discussed with respect to the surgical treatment.