Sudden reversible pacemaker failure in a patient with cardiac sarcoidosis: an unfortunate case of ventricular septal pacing.

We report a case of sudden marked deterioration of ventricular stimulation threshold resulting in pacemaker failure 16 months after a ventricular septal lead implantation for atrioventricular block. Echocardiography revealed septal wall thinning at the electrode-tissue interface, which was not detected pre-operatively. Endomyocardial biopsy confirmed cardiac sarcoidosis. The increased threshold was reversible with prednisolone.