Increased stimulation threshold in a patient with autoimmune disease: successful management with oral prednisolone and azathioprine.

We report a patient with a systemic vasculitis and heart involvement with complete atrio-ventricular block. After pacemaker implantation, the stimulation threshold significantly increased resulting in exit block. Two adjunctive ventricular leads were implanted with temporary threshold improvement. Oral glucocorticoids decreased the stimulation threshold with a transient, dose-dependent efficacy but with remarkable side effects. Azathioprine, an immunosuppressive agent, obtained a sustained decrease of the stimulation threshold.