Evaluation of a real-time magnetic resonance imaging-guided electrophysiology system for structural and electrophysiological ventricular tachycardia substrate assessment.
AIMS
Potential advantages of real-time magnetic resonance imaging (MRI)-guided electrophysiology (MR-EP) include contemporaneous three-dimensional substrate assessment at the time of intervention, improved procedural guidance, and ablation lesion assessment. We evaluated a novel real-time MR-EP system to perform endocardial voltage mapping and assessment of delayed conduction in a porcine ischaemia-reperfusion model.


METHODS AND RESULTS
Sites of low voltage and slow conduction identified using the system were registered and compared to regions of late gadolinium enhancement (LGE) on MRI. The Sorensen-Dice similarity coefficient (DSC) between LGE scar maps and voltage maps was computed on a nodal basis. A total of 445 electrograms were recorded in sinus rhythm (range: 30-186) using the MR-EP system including 138 electrograms from LGE regions. Pacing captured at 103 sites; 47 (45.6%) sites had a stimulus-to-QRS (S-QRS) delay of ≥40 ms. Using conventional (0.5-1.5 mV) bipolar voltage thresholds, the sensitivity and specificity of voltage mapping using the MR-EP system to identify MR-derived LGE was 57% and 96%, respectively. Voltage mapping had a better predictive ability in detecting LGE compared to S-QRS measurements using this system (area under curve: 0.907 vs. 0.840). Using an electrical threshold of 1.5 mV to define abnormal myocardium, the total DSC, scar DSC, and normal myocardium DSC between voltage maps and LGE scar maps was 79.0 ± 6.0%, 35.0 ± 10.1%, and 90.4 ± 8.6%, respectively.


CONCLUSION
Low-voltage zones and regions of delayed conduction determined using a real-time MR-EP system are moderately associated with LGE areas identified on MRI.
['Mukherjee|Rahul K|RK|', 'Costa|Caroline Mendonca|CM|', 'Neji|Radhouene|R|', 'Harrison|James L|JL|', 'Sim|Iain|I|', 'Williams|Steven E|SE|', 'Whitaker|John|J|', 'Chubb|Henry|H|', "O'Neill|Louisa|L|", 'Schneider|Rainer|R|', 'Lloyd|Tom|T|', 'Pohl|Thomas|T|', 'Roujol|Sébastien|S|', 'Niederer|Steven A|SA|', 'Razavi|Reza|R|', "O'Neill|Mark D|MD|"]
D000818:Animals D000075224:Cardiac Conduction System Disease D017115:Catheter Ablation D004195:Disease Models, Animal D022062:Electrophysiologic Techniques, Cardiac D008279:Magnetic Resonance Imaging D053783:Magnetic Resonance Imaging, Interventional D008297:Male D015428:Myocardial Reperfusion Injury D025321:Surgery, Computer-Assisted D034421:Sus scrofa D013552:Swine D017180:Tachycardia, Ventricular
Ventricular tachycardia Substrate Magnetic resonance imaging Late gadolinium enhancement Electroanatomic mapping Real time