Role of Bilateral Sympathectomy in the Treatment of Refractory Ventricular Arrhythmias in Arrhythmogenic Right Ventricular Dysplasia/Cardiomyopathy.

Ventricular arrhythmias in arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C) are precipitated by an increase in sympathetic activity, typically physical exercise. As such, β blockade is the cornerstone of medical treatment. However, some patients are either intolerant or refractory to β-blockers, and many continue to have arrhythmias despite catheter ablation. This report presents the case of an ARVD/C patient with severe ventricular arrhythmias refractory to β-blockade, antiarrhythmic drugs, and 3 endocardial/epicardial ventricular tachycardia (VT) ablations, who was successfully treated with bilateral sympathectomy. A previously healthy 16-year-old male triathlete presented with a sudden cardiac arrest while swimming. He was diagnosed with ARVD/C based on T-wave inversions V1–V4, 7216 premature ventricular complexes on 24-hour Holter monitoring, left bundle inferior axis VT, and subtricuspid dyskinesia with right ventricular ejection fraction 33% (Figure 1). Genetic testing revealed no pathogenic mutation in a 76-gene cardiomyopathy panel (including all 5 desmosomal genes), and he had no familial history of disease. He received a singlechamber implantable cardioverter–defibrillator (ICD) and was discharged on sotalol. Five months after discharge, the patient received his first shock for VT at 233 beats per minute while dancing. He underwent an endocardial/epicardial VT ablation (Figure 2) and was noninducible at the end of the procedure during programmed stimulation with and without isoproterenolol. He was discharged on long-acting metoprolol. Flecainide was added when palpitations recurred soon after discharge. Five months later, he experienced a VT storm requiring 43 ICD shocks after climbing stairs. He received cardiopulmonary resuscitation and regained consciousness 2 days later. He underwent a second endocardial/epicardial ablation. A stress test before discharge was normal. Amiodarone was initiated for further arrhythmia control. VT recurred 6 months later when he received 8 appropriate ICD shocks while running. In the electrophysiology laboratory, he developed spontaneous VT that promptly terminated on deep sedation. Electroanatomic mapping showed minimal signs of scar progression. Open chest epicardial cryoablation was performed with no inducible VT 5 days post ablation. One month later, the patient experienced 6 ICD shocks during exercise, and a decision was made to perform bilateral sympathectomy. Using a video-assisted thoracoscopic surgery approach, the bilateral lower half of the stellate ganglia were removed together with the second through fourth thoracic ganglia. The procedure was well tolerated and no complications occurred. To assess the impact of sympathectomy, the patient underwent noninvasive neurophysiologic testing before and after 8 weeks of sympathectomy while on the same medications (Figure 3). After sympathectomy, diastolic blood pressure responses to sympathetic stressors were similar to presympathectomy levels, whereas systolic blood pressure responses were attenuated, confirming denervation (Figure 3A). Similarly, resting heart rate was lower after sympathectomy, but augmented robustly to sympathetic stress to levels below presympathectomy values (Figure 3B). After sympathectomy, levels of finger pulse volume, the amplitude of the finger plethysmograph (Figure 3C), were higher, reflecting an overall decrease in sympathetic drive. Responses to sympathetic stress were, however, preserved. Interestingly, although finger pulse volume did not recover to baseline during the final rest period before sympathectomy, the finger pulse volume values returned to baseline after sympathectomy, showing restored capacity to attenuate sympathoexcitation when stress is withdrawn. As shown in Figure 3D, baseline skin conductance was also significantly attenuated by sympathectomy. Spectral analysis of heart rate variability demonstrated an overall reduction in sympathovagal balance (low-frequency/high-frequency ratio) from 0.58 to 0.46 (Figure 3E) because of a decrease in the low-frequency sympathetic component (1.84×10 versus 1.42×10); but not the high-frequency parasympathetic component (3.17×10 versus 3.10×10; Figure 3F). During 1-year follow-up after sympathectomy, the patient remains asymptomatic on metoprolol. His ventricular ectopy