Ventricular arrhythmias in Kearns-Sayre syndrome: A cohort study using the National Inpatient Sample database 2016-2019.

BACKGROUND: Degeneration of the cardiac conduction system resulting in complete heart block (CHB), ventricular arrhythmias (VA), and sudden cardiac death (SCD) is recognized in patients with Kearns-Sayre syndrome (KSS) and is potentially preventable with permanent pacemaker (PPM) implantation. However, other mechanisms for SCD have been proposed, and the efficacy of implanting a defibrillator instead of PPM remains to be investigated.

METHODS: We utilized the National Inpatient Sample (NIS) database 2016-2019 to investigate the risk of VA or dysrhythmic cardiac arrest (dCA) in KSS patients. We compared the outcomes of KSS to myotonic dystrophy (MD), a more common genetic disorder with similar clinical cardiac features and course.

RESULTS: We identified 640 admissions for KSS. VA or dCA were lower in admissions for KSS than MD patients (2.3% vs. 4.5%, p = .009). Device implantation differed between study groups. Approximately, 70% of cases with KSS and conduction abnormalities had pacemaker (± defibrillator) on hospital discharge, compared to 35% in MD. Conduction abnormalities were associated with higher rates of VA or dCA in both study groups. None of the admissions for KSS patients who developed VA or dCA had a pacemaker, and all of them had conduction abnormalities. One-third of admissions for MD patients who developed VA or dCA had a device already implanted prior to the event.

CONCLUSION: Despite its effectiveness in preventing VA, PPM remains underutilized in patients with KSS or MD who have conduction abnormalities. PPM alone do not fully prevent VA in MD patients; therefore, addition of defibrillator capacity might be necessary.