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Arrhythmia prevalence and sudden death risk in adults with the m.3243A>G mitochondrial disorder

Lookup NU author(s): Dr John Bourke, Dr Yi NgORCiD, Dr Matthew Bates, Emeritus Professor Doug Turnbull, Professor Grainne Gorman

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Abstract

© 2022 American Medical Association. All rights reserved. Aims To define the prevalence of non-sustained tachyarrhythmias and bradyarrhythmias in patients with the m.3243A>G mitochondrial genotype and a previously defined, profile, associated with € high sudden-death risk'. Methods and results Patients at high risk of sudden death because of combinations of ventricular hypertrophy, mitochondrial encephalopathy, lactic acidosis and stroke-like episodes family phenotype, epilepsy or high mutation load, due to the m.3243A>G mutation, were identified from a mitochondrial cohort of 209 patients. All recruited had serial ECG and echo assessments previously according to schedule, had an ECG-loop recorder implanted and were followed for as long as the device allowed. Devices were programmed to detect non-sustained brady- or tachy-arrhythmias. This provided comprehensive rhythm surveillance and automatic downloads of all detections to a monitoring station for cardiology interpretation. Those with sinus tachycardia were treated with beta-blockers and those with ventricular hypertrophy received a beta-blocker and ACE-inhibitor combination. Nine consecutive patients, approached (37.2±3.9 years, seven males) and consented, were recruited. None died and no arrhythmias longer than 30s duration occurred during 3-year follow-up. Three patients reported palpitations but ECGs correlated with sinus rhythm. One manifest physiological, sinus pauses >3.5 s during sleep and another had one asymptomatic episode of non-sustained ventricular tachycardia. Conclusions Despite € high-risk' features for sudden death, those studied had negligible prevalence of arrhythmias over prolonged follow-up. By implication, the myocardium in this genotype is not primarily arrhythmogenic. Arrhythmias may not explain sudden death in patients without Wolff-Parkinson-White or abnormal atrioventricular conduction or, it must require a confluence of other, dynamic, proarrhythmic factors to trigger them.

Publication metadata

Author(s): Bourke JP, Ng YS, Tynan M, Bates MGD, Mohiddin S, Turnbull D, Gorman GS

Publication type: Article

Publication status: Published

Journal: Open Heart

Year: 2022

Volume: 9

Issue: 1

Online publication date: 07/04/2022

Acceptance date: 22/03/2022

Date deposited: 09/05/2022

ISSN (electronic): 2053-3624

Publisher: BMJ Publishing Group

URL: https://doi.org/10.1136/openhrt-2021-001819

DOI: 10.1136/openhrt-2021-001819

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