Abstract
The most common cardiac feature of Kearns-Sayre syndrome (KSS) is atrioventricular block (AVB), and pacemaker implantations (PMIs) are recommended for KSS patients with advanced AVB. However, some KSS patients develop fatal arrhythmias such as polymorphic ventricular tachycardia (PMVT) and ventricular fibrillation (VF) and die suddenly even after PMIs. We report a patient with KSS who developed PMVT, VF, and QT prolongation, and was treated with mexiletine and successfully managed with an implantable cardioverter defibrillator (ICD). We reviewed the literature on arrhythmias in KSS published from 1975 to 2018. There were 112 patients with arrhythmia-associated KSS, 10 died, and 6 died suddenly after the PMI. The first manifestation of an arrhythmia was bundle branch block, then it progressed to AVB, and developed into complete AVB (CAVB) in about half the KSS patients. Ventricular arrhythmias were documented in 12 patients, and 8 were implanted with defibrillators afterwards. One patient after the implantation of a cardiac resynchronization therapy defibrillator (CRT-D) was treated for VF by an appropriate shock. This fact suggested that VF occurred even under proper pacing, and that defibrillators were effective. Pacemakers may suppress early afterdepolarizations (EADs) associated with a QT prolongation due to bradycardia. Similarly, mexiletine may suppress EADs by blocking the late sodium and Ca currents. Ventricular arrhythmias observed under suppression of EADs may be caused by delayed afterdepolarization (DADs) via an increasing intracellular Ca concentration due to mitochondrial dysfunction. Therefore, a PMI alone may not be sufficient to prevent sudden death, and an ICD implantation should be necessary.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.