[Pacemaker therapy in Kearns-Sayre syndrome].

Kearns-Sayre syndrome is regarded as a type of mitochondrial encephalomyopathy accompanied with mitochondrial DNA abnormality of the muscle. Diagnosis of this disease is based upon the progressive external ophthalmoplegia, atypical retinal pigmentation and cardiac conduction block. We report two clinical cases of this disorder treated with permanent pacemaker implantation at a 20 year old man (patient 1) and a 27 years old woman (patient 2). Patient 1 with bifascicular block at 19 years old progressed into complete heart block at 20 years old. Patient 2 with complete heart block was occurred "torsade de pointes." Several problems of this disease in permanent pacing should be considered the patients' small size, pacing mode selection and coexistence of congenital heart disease. Routine electrocardiography is recommended for these patients and bifascicular block in this disease constitutes a definite indication for prophylactic pacemaker implantation.