Elsevier

Heart Rhythm

Volume 20, Issue 7, July 2023, Pages 1033-1038
Heart Rhythm

Pediatric and Congenital EP
Bilateral cardiac sympathetic denervation in patients with congenital long QT syndrome

https://doi.org/10.1016/j.hrthm.2023.03.016Get rights and content

Background

Long QT syndrome (LQTS) is a potentially lethal yet treatable genetic heart disease for which left cardiac sympathetic denervation (LCSD) is a class I recommendation. Recent reports have suggested bilateral cardiac sympathetic denervation (BiCSD) as the initial surgical denervation therapy in LQTS.

Objective

The purpose of this study was to determine the frequency and settings in which BiCSD was used in a tertiary referral center with expertise in LCSD.

Methods

We performed a retrospective review of 234 out of 1638 patients with LQTS who underwent sympathetic denervation (14%) at our institution to identify the subset of patients who underwent BiCSD. Cardiac events (CEs) before LCSD, after LCSD, and after the completion of BiCSD were recorded and defined as being an appropriate implantable cardioverter-defibrillator shock, arrhythmic syncope, or sudden cardiac arrest.

Results

Only 11 patients (4.7%; 6 females [55%]) had BiCSD at our institution. Patients who received BiCSD trended toward being younger at diagnosis (6 ± 15 years vs 14 ± 13 years; P = .06) and being more likely to be symptomatic (73% vs 53%; P = .07) than the larger LCSD-only cohort. Continued CEs post-LCSD (3.8 CEs per patient on average) was the predominant determinant to return for BiCSD. Over 60 combined years of follow-up, 4 patients have not had a CE post-BiCSD while the other 7 patients average 3.6 nonlethal CEs.

Conclusion

Less than 5% of all patients receiving denervation therapy underwent BiCSD. When BiCSD was chosen, it was almost always done in a staged sequential manner beginning with LCSD first and when driven by the arrhythmogenicity of the LQTS substrate, despite otherwise optimized guideline-directed therapies.

Introduction

Long QT syndrome (LQTS) is a genetic heart disease, with an estimated prevalence of 1 in 20001 caused by pathogenic variants in the cardiac ion channel–encoding genes. The majority of LQTS is caused by pathogenic variants in the 3 canonical LQTS-causative genes: KCNQ1 (LQTS type 1 [LQT1]), KCNH2 (LQTS type 2 [LQT2]), and SCN5A (LQTS type 3 [LQT3]). LQTS is characterized by a heart rate–corrected prolonged QT (QTc) interval on the 12-lead electrocardiogram and may manifest with syncope, seizures, sudden cardiac arrest (SCA), or sudden cardiac death because of the trademark arrhythmia torsades de pointes (TdP). The mainstay treatments of LQTS include β-blockers, implantable cardioverter-defibrillator (ICD), and, more recently, left cardiac sympathetic denervation (LCSD).

First described in 1971 for LQTS,2 LCSD is now a minimally invasive operation involving the complete removal of the left sympathetic chain from the lower half of the stellate ganglion through T4.3 LCSD is an effective treatment intensifier for patients with LQTS with a very severe phenotype/clinical presentation, breakthrough cardiac events (CEs) on pharmacological treatment, or an alternative treatment for patients with LQTS who experienced significant side effects to standard pharmacotherapy (ie, β-blocker fatigue) with greatest therapeutic efficacy in LQT1. There have been several studies showing the antiarrhythmic and antifibrillatory effect of LCSD in LQTS; however, it has also been shown that a subset of patients with LQTS are nonresponsive to denervation therapy.4 Bos et al4 previously reported 5 patients with LQTS and severe phenotypes who still experienced significant CEs post-LCSD. These patients had an average QTc interval of 691 ms, and 2 of the 5 subsequently underwent right cardiac sympathetic denervation (RCSD).

Recently, more studies have reported utilization of combination LCSD and RCSD, or bilateral cardiac sympathetic denervation (BiCSD), for the treatment of ventricular arrhythmias, with some suggesting a bilateral approach right away.5,6 Thus, the aim of this study was to report the outcomes of patients with both LQTS and BiCSD as part of their treatment program.

Section snippets

Methods

After institutional review board approval, we performed a retrospective review of the electronic medical record of all patients evaluated between 2005 (the beginning of our denervation surgical program) and 2021 in the Mayo Clinic Windland Smith Rice Genetic Heart Rhythm Clinic with LQTS and LCSD to identify the subset of patients who underwent BiCSD. Abstracted data included patient demographic characteristics, family history, CE details before LCSD, after LCSD, and after RCSD, and finally,

Results

Overall, only 11 of 234 patients with LQTS who underwent LCSD (4.7%) also underwent RCSD. Further, only 1 of these 11 patients underwent complete BiCSD as their first surgery while the others had sequential BiCSD beginning with LCSD first. Of these, 6 of 11 (54.5%) were female, and the average age at diagnosis was 6.5 ± 15.0 years (Table 1). When subcategorized by genotype, 4 patients (36.4%) had LQT1, 5 (45.4%) had LQT3, and 2 (18.2%) had a pathogenic variant in a minor LQTS-susceptibility

Discussion

For LQTS, LCSD is a viable treatment intensifier for patients with a history of CEs, a treatment alternative for side effects to standard pharmacotherapies,3 or, as we have shown more recently, for some patients as an effective LQTS monotherapy.7 LCSD is currently a class I recommendation by the Heart Rhythm Society for high-risk patients with LQTS who refuse or have a contraindication for ICD therapy, those who do not tolerate β-blockers, or for those who experience continued CEs while on

Conclusion

Less than 5% of all patients receiving denervation therapy at our LQTS specialty center have undergone BiCSD. These patients have had a significant clinical course in regard to their LQTS, and multiple other guideline-directed therapies were trialed before performing staged BiCSD. Given the successful 50-year experience of LCSD as a treatment option for patients with LQTS, sequential LCSD followed by RCSD to complete BiCSD is seldom necessary (>95% of the time) and therefore the notion of

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Funding Sources: This work was supported by the Mayo Clinic Windland Smith Rice Comprehensive Sudden Cardiac Death Program (Dr Ackerman) and Mayo Clinic Center for Clinical and Translational Science through grant number UL1TR002377 from the National Center for Advancing Translational Sciences, a component of the National Institutes of Health.

Disclosures: Dr Ackerman is a consultant for Abbott, Boston Scientific, Bristol Myers Squibb, Daiichi Sankyo, InVitae, Medtronic, Thryv Therapeutics, and UpToDate. Dr Ackerman and Mayo Clinic have an equity/intellectual property/royalty relationship with AliveCor, Anumana, ARMGO Pharma, and Pfizer. The remaining authors have nothing to disclose.

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