Authors describe a case of partial atrio ventricular septal defect--cushion defect--with only a mitral valve cleft and mild valvular insufficiency. There were present also, since the childhood, an atrio ventricular primary block, and a left axis deviation. Late appeared a RBBB. The correct diagnosis has been done at the age of 67 years. The patient refers mean rhythm disorders and effort dyspnea. She refused surgical correction successful also in the late age.