Cardiac Outcomes in Adults With Mitochondrial Diseases.

Background: Patients with mitochondrial diseases are at risk of heart failure (HF) and arrhythmic major adverse cardiac events (MACE).
Objectives: We developed prediction models to estimate the risk of HF and arrhythmic MACE in this population.
Methods: We determined the incidence and searched for predictors of HF and arrhythmic MACE using Cox regression in 600 adult patients from a multicenter registry with genetically confirmed mitochondrial diseases.
Results: Over a median follow-up time of 6.67 years, 29 patients (4.9%) reached the HF endpoint, including 19 hospitalizations for nonterminal HF, 2 cardiac transplantations, and 8 deaths from HF. Thirty others (5.1%) reached the arrhythmic MACE, including 21 with third-degree or type II second-degree atrioventricular blocks, 4 with sinus node dysfunction, and 5 sudden cardiac deaths. Predictors of HF were the m.3243A>G variant (HR: 4.3; 95% CI: 1.8-10.1), conduction defects (HR: 3.0; 95% CI: 1.3-6.9), left ventricular (LV) hypertrophy (HR: 2.6; 95% CI: 1.1-5.8), LV ejection fraction <50% (HR: 10.2; 95% CI: 4.6-22.3), and premature ventricular beats (HR: 4.1; 95% CI: 1.7-9.9). Independent predictors for arrhythmia were single, large-scale mtDNA deletions (HR: 4.3; 95% CI: 1.7-10.4), conduction defects (HR: 6.8; 95% CI: 3.0-15.4), and LV ejection fraction <50% (HR: 2.7; 95% CI: 1.1-7.1). C-indexes of the Cox regression models were 0.91 (95% CI: 0.88-0.95) and 0.80 (95% CI: 0.70-0.90) for the HF and arrhythmic MACE, respectively.
Conclusions: We developed the first prediction models for HF and arrhythmic MACE in patients with mitochondrial diseases using genetic variant type and simple cardiac assessments.
Competing Interests: Funding Support and Author Disclosures This study was funded by grants from the Association Française contre les Myopathies (French Alliance against Myopathies), which was not involved in the design and conduct of the study; the collection, management, analysis, and interpretation of the data; the preparation, review or approval of the manuscript; nor in the decision to submit the manuscript for publication. Dr Pitceathly is supported by a Medical Research Council (United Kingdom) Clinician Scientist Fellowship (MR/S002065/1). Drs Pitceathly and Hanna receive funding from a Medical Research Council (United Kingdom) strategic award to establish an International Centre for Genomic Medicine in Neuromuscular Diseases (ICGNMD) (MR/S005021/1). Dr Lopes is supported by a Medical Research Council (United Kingdom) clinical academic partnership (CARP) award. Dr Quinlivan was funded by National Institute for Health and Care Research Biomedical Research Centre, University College Hospitals Foundation Trust. The University College London Hospitals/University College London Queen Square Institute of Neurology sequencing facility receives a proportion of funding from the Department of Health's National Institute for Health and Care Research Biomedical Research Centre’s funding scheme. The clinical and diagnostic “Rare Mitochondrial Disorders” Service in London is funded by the U.K. NHS Highly Specialised Commissioners. Dr Elliott has received consultancy fees from Pfizer, Sanofi, Sarepta, DinaQor, Freeline, Novo Nordisk, and Bristol Myers Squibb. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose.
(Copyright © 2022 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)