Recurrence of myocarditis presenting as pacing and sensing failure after implantation of a permanent pacemaker at first onset.

A 31-year-old woman was admitted to hospital with loss of consciousness and generalized convulsions. Electrocardiography (ECG) showed complete atrioventricular block (AV block) with a pulse rate of 30 beats/min. Endomyocardial biopsy from the right ventricle showed massive necrosis and degeneration of myocardial cells with extensive infiltration of lymphocytes into the interstitial space. These pathological findings suggested fulminant myocarditis. Following glucocorticoid therapy, the patient became asymptomatic, but the AV block did not resolve completely and a bifocal pacemaker was implanted. However, similar symptoms recurred 7 years later. An ECG showed pacing and sensing failure linked to an increase in the pacing threshold and a decrease in the sensing threshold. Endomyocardial biopsy from the right ventricle again showed interstitial infiltration with lymphocytes and eosinophils. After glucocorticoid therapy, she became asymptomatic once more, and the improvement in the pacing and sensing failure, and cardiomegaly, was satisfactory. This patient represents a very rare case of recurrence of acute myocarditis without progression, as much as 7 years after its first occurrence. Glucocorticoid therapy was still effective in treating the recurrent myocarditis presenting with pacing and sensing failure.