Abstract 19222: Persistence of Late Potentials Found during Repeat Ablation of Ventricular Tachycardia: A Mechanism for Recurrence?

Abstract

Background: Recurrence of scar-mediated ventricular tachycardia (VT) approaches 50% in patients at 6-12 months. Outcomes from multiple procedures are not well characterized. Changes in electroanatomic substrate and the persistence of late potentials (LP) during a repeat procedure have not been reported. Methods: Patients who underwent both initial and repeat VT ablation between 2004-11 at Ronald Reagan UCLA Medical Center were analyzed. Electroanatomic maps (NAVX, St. Jude Medical, Minneapolis, MN and CARTO, Biosense-Webster, Diamond Bar, CA) from both the initial and repeat ablation procedures were analyzed for LP, defined as low-voltage electrograms with onset outside of the QRS complex. All studies were adjudicated by a second observer. Results: 23 patients underwent both initial and repeat ablation at our institution, of which 16 patients had electroanatomic maps from both studies available for analysis. There were 3 patients who underwent 3 ablations, and the rest underwent a single repeat procedure. Substrates included 10 non-ischemic cardiomyopathy (NICM), 4 ischemic cardiomyopathy (ICM), and 2 arrhythmogenic right ventricular dysplasia (ARVD). The overall success rate, defined as no VT recurrence at 1 year, was 25% (4/16) (ARVD=2, ICM=2). All patients (13/13) who had LP identified on initial procedure had persistence of LP on repeat procedure. The remaining patients (3/3) who had no LP identified on initial procedure, again had no LP targets on repeat ablation. Conclusions: In this retrospective consecutive series of patients with recurrent VT, those with LP identified on the initial procedure exhibited persistence of LP during repeat mapping and ablation. This may be an important mechanism of recurrence, suggesting that more extensive substrate modification of all late activity is necessary. In patients without LP identified on the initial procedure, no LP were identified on repeat mapping. In patients that require repeat ablation, 25% experience freedom from VT recurrence at 1 year after their last procedure.