Global cardiac sympathetic denervation is associated with diffuse myocardial fibrosis in non-ischemic cardiomyopathy

Abstract Funding Acknowledgements Type of funding sources: None. Background Occurrence of ventricular tachycardias (VT) has been related to changes in sympathetic innervation and myocardial tissue in ischemic cardiomyopathy. In non-ischemic cardiomyopathy (NICM) patients with VT, the relation between global cardiac sympathetic innervation and non-ischemic fibrosis is less clear. The current gold standard in electrophysiology to identify non-ischemic fibrosis relies on unipolar endocardial voltage mapping. Objective To establish the relationship between global cardiac sympathetic innervation and global fibrosis. Methods 29 patients (93% male, 58 ± 14 years, mean LVEF 38%±13) from the ‘Leiden Nonischemic Cardiomyopathy Study’ undergoing VT ablation between 2011-2018 were included. Endocardial voltage mapping was performed and the mean endocardial unipolar voltage (UV) was taken as a surrogate for global fibrosis. Global cardiac sympathetic innervation was analyzed by 123-I-MIBG imaging using heart-to-mediastinum ratio (HMR). A cut-off of 1.8 was used to delineate between normal (>1.8) and denervated (<1.8). HMR was correlated with mean UV. Results For patients with global cardiac sympathetic denervation a linear relationship was present between HMR and mean UV (R = 0.5278, P = 0.0431. There was no significant linear relationship for patients with normal cardiac sympathetic innervation between HMR and mean UV (R=-0.1696, P = 0.5795). Conclusion Global cardiac sympathetic denervation is related to myocardial fibrosis in patients with NICM and VT. The data support an interplay between denervation and fibrosis which may contribute to arrhythmogeneity, as observed in ICM. Abstract Figure.