Catheter Ablation -> Ventricular Arrhythmias -> Ablation Techniques D-PO05 - Poster Session V (ID 39) Poster

D-PO05-185 - High Resolution Characterization Of Peri-Aortic VT: Arrhythmia Mechanisms And Circuit Delineation (ID 585)


Background: Peri-aortic substrate is an increasingly recognized clinical entity of scar-related ventricular tachycardia (VT).
Objective: To investigate the characteristics of the peri-aortic VT substrate and reentrant mechanisms in patient with structural heart disease with ultra-high-density mapping.
Methods: Twenty-six peri-aortic VT in 19 patients with cardiomyopathy (males: 19, median age: 63±8 years, EF: 35±12%, ischemic: 3) were analyzed. Peri-aortic VT was defined as low voltage substrate within 2 cm adjacent to the aortic root with isthmus, exit, or VT termination during ablation.
Results: All the patients had peri-aortic scar (< 0.5mV) that occupied 60±24% of peri-aortic region during sinus rhythm (mean scar area 16±8 cm2). Septal involvement was observed in 70% of the patients. LAVA and late potentials were recorded within the in peri-aortic region in 100% and 75% of the patients, respectively. VT activation mapping showed reentry in 57% and focal breakout pattern in 43%. In reentrant VT, 44% had figure-right circuit and 56% had single loop circuit. The isthmus length and dimension were 14±5 mm and 1.9±1.2 cm2, respectively. VT critical site was more frequently located at the septal side compared to the mitral annulus side (77% vs. 23%). Radiofrequency ablation terminated 73% (21/26) of VT within 13±6 mm from aortic root. At a mean follow-up of 12±9 months, freedom from VT recurrence at 1 year was 50%.
Conclusion: VT originating from peri-aortic substrate was demonstrated to be locally reentrant in over half of the cases. Focal patterns may still represent intramural reentry. Septal extension was commonly observed, which may account for the high rate of recurrence in 50%.