Cardiac Sympathetic Denervation for Refractory Ventricular Arrhythmias

Abstract

Background: Cardiac sympathetic denervation (CSD) has been shown to reduce the burden of implantable cardioverter-defibrillator (ICD) shocks in small series of patients with structural heart disease (SHD) and recurrent ventricular tachyarrhythmias (VT).

Objectives: This study assessed the value of CSD and the characteristics associated with outcomes in this population.

Methods: Patients with SHD who underwent CSD for refractory VT or VT storm at 5 international centers were analyzed by the International Cardiac Sympathetic Denervation Collaborative Group. Kaplan-Meier analysis was used to estimate freedom from ICD shock, heart transplantation, and death. Cox proportional hazards models were used to analyze variables associated with ICD shock recurrence and mortality after CSD.

Results: Between 2009 and 2016, 121 patients (age 55 ± 13 years, 26% female, mean ejection fraction of 30 ± 13%) underwent left or bilateral CSD. One-year freedom from sustained VT/ICD shock and ICD shock, transplant, and death were 58% and 50%, respectively. CSD reduced the burden of ICD shocks from a mean of 18 ± 30 (median 10) in the year before study entry to 2.0 ± 4.3 (median 0) at a median follow-up of 1.1 years (p < 0.01). On multivariable analysis, pre-procedure New York Heart Association functional class III and IV heart failure and longer VT cycle lengths were associated with recurrent ICD shocks, whereas advanced New York Heart Association functional class, longer VT cycle lengths, and a left-sided-only procedure predicted the combined endpoint of sustained VT/ICD shock recurrence, death, and transplantation. Of the 120 patients taking antiarrhythmic medications before CSD, 39 (32%) no longer required them at follow-up.

Conclusions: CSD decreased sustained VT and ICD shock recurrence in patients with refractory VT. Characteristics independently associated with recurrence and mortality were advanced heart failure, VT cycle length, and a left-sided-only procedure.

Keywords: antiarrhythmic drugs; autonomic nervous system; functional class; implantable cardioverter-defibrillator; orthotopic heart transplantation.

FIGURE 1. Freedom from Individual Endpoints

Freedom from (A) sustained ventricular tachyarrhythmias (VT) or implantable cardioverter-defibrillator (ICD) shock as well as (B) freedom from death or orthoptopic heart transplantation (OHT) slowed after 1 year.

FIGURE 2. Sustained Survival

Similar sustained VT/ICD shock-free, transplant-free survival is seen in (A) the overall population and (B) in patients with ischemic cardiomyopathy (ICM) compared to patients with nonischemic cardiomyopathy (NICM). Abbreviations as in Figure 1.

FIGURE 3. Bilateral Versus Left CSD

There was a significant difference in the combined endpoint between bilateral and left cardiac sympathetic denervation (CSD). Abbreviations as in Figure 1.

FIGURE 4. Effect of NYHA Class on Outcomes

Worsening New York Heart Association (NYHA) class significantly diminished CSD effectiveness on outcomes. Abbreviations as in Figures 1 and 3.

Figure 5. Pre-procedural Characteristics Associated with VT/ICD Shock Recurrence after CSD

Advanced NYHA class and longer VT cycle length (CL) predicted recurrence of sustained VT and ICD shock. AAD = antiarrhythmic drug; CI = confidence interval; CKD = chronic kidney disease; other abbreviations as in Figures 1, 3, and 4.

CENTRAL ILLUSTRATION. Pre-procedural Variables Associated With VT-free Transplant-free Survival after CSD

Patients with structural heart disease and recurrent ventricular tachyarrhythmias (VT) underwent cardiac sympathetic denervation (CSD) and were assessed for VT or implantable cardioverter-defibrillator (ICD) shock, death, or orthoptopic heart transplantation (OHT). On mulitvariable analysis, advanced New York Heart Association (NYHA) class, longer VT cycle lengths (CL), and a left-sided only procedure predicted the combined endpoint. AAD = antiarrhythmic drug; CI = confidence interval; CKD = chronic kidney disease; DMII = type 2 diabetes mellitus. Hazard ratio for VT CL refers to every 20 ms increase in cycle length.