Sudden cardiac death (SCD) due to ventricular arrhythmias is by far the leading cause of mortality in the USA resulting in 250,000 deaths/year. The standard of care for patients with history of ventricular tachy-arrhythmia (VT) or those at risk for these arrhythmias has included implantable cardiac defibrillators (ICD) in addition to routine care. Cardiac Sympathetic Denervation (CSD) is an emerging procedure for patients with recurrent ventricular tachyarrhythmias (VT). Bilateral CSD involves the removal of the lower one half of the bilateral stellate ganglia and the thoracic ganglia of T2 – T4. Bilateral CSD has previously been shown to decrease the amount of painful ICD shocks for patients with VT due to the blockade of the sympathetic nervous system. The purpose of this study is to determine if CSD is more effective in specific patient subtypes with cardiomyopathy than others.
Clinical data was analyzed from patients that have undergone CSD at UCLA, Johns Hopkins, Columbia, and India. Through the curation of a combined database that tracks patients and records specific patient-related metrics (including but not limited to: date of CSD, date of first VT recurrence requiring shock, and date of death), sub-populations of the overall set of patients (n=146) were compared to see if there are significant differences in survival or shock-free time among the groups. Using data extracted from the data base, subtypes of patients based on cause of cardiomyopathy were compared (Chagas, arrhythmogenic right ventricular dysplasia (ARVD), hypertrophic cardiomyopathy (HCM), idiopathic, ischemic, and sarcoid). Two metrics were compared between subtypes: survival time after the procedure as well as time living until first VT recurrence requiring ICD shock. Kaplan Meier survival curves were generated to compare the 6 groups.
Using the combined database (N=146) we first determined the subtypes of patients to compare. We established endpoints based on the clinical data available, including time to shock and survival. Although some trends were noted, we determined that due to the small number of patients that have undergone CSD and the limited number of patient follow up visits, additional data will be needed to accurately distinguish (establish significant difference) between patient subtypes. As more patient data is collected for the patient subtypes, additional endpoints will be analyzed and compared for benefit including exercise testing and heart rate variability from Holter monitors pre and post CSD.