Abstract 17789: Three-dimensional 123I-Meta-iodobenzylguanidine (123I mIBG) Cardiac Innervation Maps to Guide Ablation of Ventricular Tachycardia - A Novel Paradigm Introducing Innervation Imaging in Ablation Therapy
Introduction: Cardiac innervation is a critical component of cardiac arrhythmogenesis, but regional sympathetic innervation has not assessed to possibly guide VT ablations.
Methods: 15 patients with ischemic cardiomyopathy underwent cardiac 123I mIBG imaging prior to VT ablation. Short axis 4h-delayed SPECT images were used to create 3D innervation maps, which were registered to high-density voltage maps. Areas of regional denervation identified by two expert readers were compared to voltage-defined scar (<0.5 mV bipolar, <5.8 mV unipolar) or border zone (BZ, <1.5 mV bipolar) and successful ablation sites.
Results: 3D innervation maps demonstrated areas of complete denervation and 123I mIBG BZ in all patients. Denervated areas were 2.8 times larger than bipolar scar (26.9 ± 9.7% vs. 10.9 ± 8.8%, p<0.001). BZ of 123I mIBG denervation was non-significantly smaller than bipolar-defined BZ (12.3 ± 5.9% vs. 16.3 ± 6.4%, p=1.01). Similarly, in segmental analysis, denervation was seen in 9.5 ± 1.5 segments of the left ventricle, while 7.7 ± 3.4 segments had bipolar scar.
Bipolar and unipolar voltages varied widely within areas of complete denervation (1.3 ± 1.5mV and 4.4± 2.3mV) and 123I mIBG transition zone (1.5±1.8mV and 5.0± 2.6mV). Bipolar voltage measurements of mapping points in the denervated area and 123I mIBG transition zone were in the scar (<0.5mV), border zone (0.5-1.5mV) and normal category (>1.5mV) in 35%, 36% and 29% as well as 35%, 35% and 30%, respectively.
Ablation sites were within voltage defined scar in 7% (n=1: 0.4 mV) and border zone in 64% (1.0 ± 0.3 mV). Ablation sites were within areas of normal bipolar voltage in the remaining 29% of cases (3.4 ±1.7 mV). Successful ablation sites were within denervated myocardium and 123I mIBG transition zone in 50% and 50%, respectively. No successful ablation sites were within normally innervated myocardium.
Conclusion: 123I mIBG innervation defects are significantly larger than voltage-defined scar and cannot be reliably detected with typical voltage criteria. Successful VT ablation sites were frequently within areas of preserved voltage but abnormal innervation. This suggests that 3D MIBG innervation maps may have a role in guiding VT ablation in ischemic cardiomyopathy.
Author Disclosures: T. Klein: None. M.S. Abdulghani: None. R. Asoglu: None. R. Huang: None. M. Smith: None. B. Remo: None. A. Turgeman: None. O. Mesubi: None. S. Sidhu: None. A. Saliaris: None. V. See: None. S. Shorofsky: None. W. Chen: None. V. Dilsizian: Research Grant; Modest; GE. T. Dickfeld: Research Grant; Modest; Biosense and GE. Consultant/Advisory Board; Modest; Biosense.
- © 2014 by American Heart Association, Inc.