Impact of cardiac sympathetic denervation on electrical storms in patients with cardiomyopathies
Authors: Dusi V , Ruffinazzi M , Pugliese L , Guerrera F , Vicentini A , Savastano S , Greco A , Camporotondo R , Frea S , Vairo A , Imazio M , Tritto M , Raineri C , Rordorf R , De Ferrari G M 
Published: May 2023

Abstract

Funding Acknowledgements
Type of funding sources: None.

Background
Cardiac Sympathetic Denervation (CSD) has been recently proposed for the treatment of refractory ventricular arrhythmias (VAs) in patients with cardiomyopathy (CMP). A multicentric American case series suggested a greater efficacy of the bilateral (BCSD), compared to the left-side only procedure (LCSD), albeit with a potential impact on chronotropism. The impact of CSD on the risk of electrical storms (ES) in CMP has never been evaluated.

Purpose
To describe our multicenter experience with CSD in CMP patients with refractory VAs, with a specific focus on ES incidence.

Methods
Thirty patients with CMP and refractory VAs underwent either LCSD or BCSD between April 2016 and June 2022. Among them, one patient received first LCSD and then right-side CSD due to ES recurrence after LCSD: to properly assess the risk of ES after LCSD and BCSD he was included in both groups, leading to 5 cases of LCSD and 26 cases of BCSD. All patients had a Video-Assisted Thoracoscopic Surgery, in 8 cases with the robotic technique. The main reason (3/5 cases, 60%) to perform LCSD instead of BCSD since the beginning was sinus bradycardia in single ICD lead recipients.

Results
87% of pts were male, mean age was 56 ± 16 yrs and mean LVEF 31± 12%; most (n=26, 85%) suffered non-ischemic CMP and 37% were in NYHA class ≥3. Main indications for CSD were refractory polymorphic/fast VAs in 60% of pts and refractory monomorphic VAs in the rest. Except for 5 patients (17%) with previous thyrotoxicosis, the majority were either on amiodarone (n=19, 63%) or on sotalol (n=3, 10%) and 53% had previously undergone ≥1 catheter ablation for VAs. The median follow-up (FU) after CSD was 16 months (IQR 6-42 months).
No major complications occurred. Eleven patients (37%) either died during FU (n=8, 27%), mostly due to end-stage heart failure, or underwent heart transplant (n=3, 10%). After CSD, the percentage of patients with ES decreased from 77% to 40% (p&lt;0.01), while patients with appropriate shocks decreased from 100% to 60%. The figure shows the significant impact of CSD on VT burden. The antiarrhythmic benefit was more pronounced after BCSD: ES incidence decreased from 85% to 39% (p&lt;0.01), ICD shock incidence from 100% to 54% (p&lt;0.01), while no significant changes in ES and ICD shock incidence were observed after the few LCSD procedures (n=5). Survival free from ICD shock at 1 year was better among patients with a NYHA class &lt;3 (73% versus 15%, p&lt;0.001).

Conclusions
Our case series of CSD in CMP represents the largest reported in Europe and the first one to evaluate the impact of CSD on electrical storms. The occurrence of electrical storms was more than halved by BCSD confirming the powerful protective effect also on this ominous phenomenon. The greater antiarrhythmic benefit observed among patients with better functional class suggests the opportunity to perform this procedure earlier on in the trajectory of patients with progressive heart failure.