[New aspects of the Kearns-Sayre syndrome].

The case report of the 23 years old female with Kearn-Sayre syndrome started about 15 years ago has some special cardiological aspects. By His band ECG the height of III. degree atrioventricular block was located in the atrioventricular node which is in sharp contrast with all former findings localizing the block into or distal to His band. In the pathogenesis of the unexpected block localisation--besides the muscular degeneration accepted generally in KSS--the recent myocardial infarction of the patient could have a causal role. Electronmicroscopical investigation carried out on the biopsy specimen from the right ventricle revealed both the characteristic hallmarks of "generalized mitochondriopathy" and the pathological glycogen accumulation having been published in skeletal muscles before. The mitral valve prolaps diagnosed in the patient has never been mentioned in KSS. Trauma suffered in early childhood might have a pathogenetic role. In discordance with literature steroid treatment of the diabetic patient with KSS didn't result in lactacidosis.