Safety and Outcomes of Ventricular Tachycardia Substrate Ablation During Sinus Rhythm: A Prospective Multicenter Registry.

Objectives: This study sought to analyze safety and outcomes of ventricular tachycardia (VT) substrate ablation during sinus rhythm (SR), without baseline VT induction.

Background: Safety and outcomes after scar-related VT ablation during SR are not well known. Hemodynamic instability and need for electrical cardioversion can compromise safety of VT ablation procedures.

Methods: Four hundred twelve consecutive patients with structural heart disease undergoing VT ablation were included in a prospective multicenter registry. Substrate ablation during SR, without baseline VT induction, was the first step of the ablation procedure and the standard protocol. Scar dechanneling was the substrate ablation technique used. VT inducibility was tested after substrate ablation.

Results: VT induction protocol was negative after substrate ablation in 289 patients (70.1%), completing the procedure in SR. Procedure-related complication rate was 6.5%, including 1 death (0.2%). Thirty-day mortality after first VT ablation procedure was 1.7%. Overall survival was 95.8% and 88.6% at 1 and 3 years of follow-up, respectively. In a multivariable proportional hazards regression model, age ≥70 years (hazard ratio [HR]: 4.95 [2.59 to 9.47]; p < 0.001), chronic obstructive pulmonary disease (HR: 2.37 [1.24 to 4.52]; p = 0.008), left ventricular ejection fraction <30% (HR: 2.43 [1.37 to 4.33]; p = 0.002), and incomplete substrate ablation (HR: 2.37 [1.24 to 4.52]; p = 0.026) were independent predictors of overall mortality. At 12 months' follow-up, VT-free survival was 82.5% after 1 procedure and 87.8% after n procedures CONCLUSIONS: Substrate ablation during SR avoiding multiple VT induction has low procedure-related complications and low early mortality. Age, chronic obstructive pulmonary disease, and reduced left ventricular ejection fraction, but also incomplete substrate elimination, are predictors of mortality.