Abstract 19312: Multiplexed Images of the Heart Provide Novel Functional Information to Guide Invasive Procedures: A Review of the Initial Case Series

Abstract

Introduction: The novel, high sensitivity and dedicated cardiac camera (D-SPECT, Spectrum Dynamics) allows single or dual tracer studies to add functional information to 3D DICOM image information from CT or CMR. Information consists of either perfusion information (from (technetium-99m (Tc-99m) methoxyisobutylisonitrile (MIBI, for perfusion) and/or sympathetic nnervation information using meta-iodobenzylguanidine (mIBG). Merging these 3D images with invasive 3D electroanatomical maps (EAM) offers image integration on a function rather than geometrical level alone. These fused 3D images can be combined with EAM to guide ablation procedures for either atrial or ventricular arrhythmias. Methods: A total of 23 patients (15 male, mean age 59.9 yrs) underwent either single iodine-123 mIBG (n=10, for sympathetic innervation) or dual tracer (n= 13, mIBG+MIBI, for perfusion) imaging and the acquired information was fused with the 3D cCT or CMR using a custom-made software. Results: Twenty out of 23 patients underwent invasive electrophysiology studies which targeted either atrial or ventricular arrhythmias. During the atrial arrhythmia procedures, high uptake sites for mIBG was correlated to positive effect of high frequency stimulation (=transient prolongation of AV nodal conduction) and thereby confirming ganglionated plexi which were targeted in addition to the standard ablation. Patients with ventricular arrhythmia, low amplitude voltage mapping showed good correlation to the perfusion scar imaging, thereby serving as a substrate map even in patients with implantable devices. Interestingly, regions of mismatch where identified which proved to be pro-arrhythmogenic during EP study in the 4/6 patients who underwent ventricular tachycardia (VT) ablation. Conclusion: The combination of innervation (by mIBG) and perfusion (by MIBI) nuclear imaging in addition to the 3D cCT or CMR imaging provides a novel type of “road map” information for complex arrhythmia ablation by providing a region of mismatch of innervation and perfusion. This provides a novel substrate information even in the presence of implantable devices.