Background

Bilateral cardiac sympathetic denervation (BCSD) is an effective therapy for ventricular arrhythmias (VAs) in cardiomyopathies (CMPs). After BCSD, residual autonomic nervous system (ANS) function is unknown.

Objective

The purpose of this study was to assess ANS responses in patients with CMP before and after BCSD as compared with demographically matched healthy controls.

Methods

Patients with CMP undergoing BCSD and matched healthy controls were recruited. Noninvasive measures-finger cuff beat-to-beat blood pressure (BP), electrocardiography, palmar electrodermal activity (EDA), and finger pulse volume (FPV)-were obtained at rest and during autonomic stressors-posture change, handgrip, and mental stress. Maximal as well as specific responses to stressors were compared.

Results

Eighteen patients with CMP (mean age 54 ± 14 years; 16 men, 89%; left ventricular ejection fraction 36% ± 14%) with refractory VAs and 8 matched healthy controls were studied; 9 patients with CMP underwent testing before and after (median 28 days) BCSD, with comparable ongoing medication. Before BCSD, patients with CMP (n = 13) had lower resting systolic BP and FPV than did healthy controls (P < .01). Maximal FPV and systolic BP reflex responses, expressed as percent change were similar, while diastolic BP, mean BP, and EDA responses were blunted. After BCSD, resting measurements were unchanged relative to presurgical baseline (n = 9). EDA responses to stressors were abolished, confirming BCSD, while maximal FPV and BP responses were preserved. Diastolic BP, mean BP, and FPV responses to orthostatic challenge pointed toward a better tolerance of active standing after BCSD as compared with before. Responses to other stressors remained unchanged.

Conclusion

Patients with CMP and refractory VAs on optimal medical therapy have detectable but blunted adrenergic responses, which are not disrupted by BCSD.

Background

Cardiac sympathetic denervation (CSD) is a promising treatment for patients with structural heart disease (SHD) and refractory ventricular tachyarrhythmias (VTs). The effect of CSD on atrial rhythm as well as the prognostic impact of atrial arrhythmias (AAs) or left atrial volume index (LAVI) on CSD outcome are unknown.

Objectives

The goals of this study were to evaluate the impact of AAs and LAVI on CSD outcome and to assess changes in AAs burden and in atrial pacing after CSD.

Methods

Patients with SHD undergoing CSD for VTs were analyzed. Hazards models were built to assess predictors of sustained VT/implantable cardioverter-defibrillator (ICD) shock recurrences and death/orthotopic heart transplant (OHT). Changes before vs after CSD were assessed using ICD, clinical, and echocardiographic data. A drug index was devised to correct for medication use.

Results

Between 2009 and 2018, 91 patients (mean age 56 ± 13 years; mean left ventricular ejection fraction 34% ± 14%; 47% with a history of AAs) underwent left CSD (16%) or bilateral CSD (BCSD). The median follow-up was 14 months (interquartile range 4-37 months). Using multivariable analysis, neither LAVI nor AAs were associated with recurrences; LAVI was an independent predictor of death/OHT. AAs burden did not change after BCSD, but atrial pacing increased from a median of 28% to 72% (P < .01). Left ventricular end-diastolic diameter slightly increased; however, sustained VT/ICD shocks were reduced.

Conclusion

In patients with SHD undergoing CSD, LAVI predicts death/OHT. AAs burden, already low at baseline, was unchanged after BCSD, while the need for atrial pacing increased, suggesting an impact of BCSD on sinus node chronotropism.

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.

Background Cardiac sympathetic denervation (CSD) has been used as a bailout strategy for refractory ventricular tachycardia (VT). Risk of VT recurrence in patients with scar-related monomorphic VT referred for CSD and the extent to which CSD can modify this risk is unknown. We aimed to quantify arrhythmia recurrence risk and impact of CSD in this population. Methods and Results Adjusted competing risk time to event models were developed to adjust for risk of VT recurrence and sustained VT/implantable cardioverter-defibrillator shocks after VT ablation based on patient comorbidities at the time of VT ablation. Adjusted VT and implantable cardioverter-defibrillator shock recurrence rates were estimated for the subgroup who subsequently required CSD after ablation. The expected adjusted recurrence rates were then compared with the observed rates after CSD. Data from 381 patients with scar-mediated monomorphic VT who underwent VT ablation were analyzed, excluding patients with polymorphic VT. Sixty eight patients underwent CSD for recurrent VT. CSD reduced the expected adjusted VT recurrence rate by 36% (expected rate of 5.61 versus observed rate of 3.58 per 100 person-months, P=0.01) and the sustained VT/implantable cardioverter-defibrillator shock rates by 34% (expected rate of 4.34 versus observed 2.85 per 100 person-months, P=0.03). The median number of sustained VT/implantable cardioverter-defibrillator shocks in the year before versus the year after CSD was reduced by 90% (10 versus 1, P<0.0001). Conclusions Patients referred for CSD for refractory scar-mediated monomorphic VT are at a higher risk of VT recurrence after ablation as compared with those not requiring CSD, mostly because of their cardiac comorbidities. CSD significantly reduced both the expected risk of recurrences and VT burden.