Cardiac dysfunction, including congestive heart failure and impulse conduction abnormalities, have been implicated in the sudden death of patients suffering from the Kearns-Sayre syndrome. This report describes a 29-year-old woman who suffered syncopal episodes due to sustained polymorphic VT. Sustained polymorphic VT was not associated with prolongation of the QT interval or bradycardia on the ECG. The implantation of a cardioverter defibrillator should be considered in this syndrome.