[Electrophysiologic findings in patients with Kearns-Sayre syndrome--report on 2 cases].

The Kearns-Sayre syndrome is identified by the triad of progressive external ophthalmoplegia, atypical pigmentary retinopathy, and conduction disturbances. In addition, clinical manifestations may include mental retardation, sensorineural deafness, cerebellar ataxia, and facial and peripheral muscle weakness. Morphologic alterations in skeletal muscle may be characterized by ragged-red fibers. Two patients with Kearns-Sayre syndrome underwent electrophysiological examination. The first patient had a first and second degree AV block (Mobitz type II), right bundle branch block, and left axis deviation. The His-bundle electrogram showed a prolonged HV interval as a hint at an intraventricular conduction delay. The signal-averaging technique and endocardial mapping revealed ventricular after-depolarizations. The second patient had an unsuspicious ECG, recurrent atrial tachycardias, normal atrial and ventricular conduction, and after-depolarizations in endocardial mapping. Two months later he showed a second degree AV block combined with clinical symptoms. Pacemakers were implanted in both patients. Beside disturbances of the conduction system in both patients signs of electrical instability of the myocardium were found. In this way the Kearns-Sayre syndrome may be seen as a form of cardiomyopathy.