We present the case of a 72 years old female with multiple episodes of atrial fibrillation, interatrial block and different degrees of atrioventricular block, that died because of stroke. Postmortem pathologic examination showed a lipomatous hypertrophy of the interatrial septum (previously suspected on echocardiogram), his bundle and right branch degeneration as well as mitral annular calcification extended to conduction system. According to these pathologic findings, rhythm and conduction disturbances are correlated with the two levels (atrial and atrioventricular) where anatomic abnormalities were found.