Abstract 16917: Enodcardial Scar Size Predicts Adverse Outcomes Following Radiofrequency Catheter Ablation in Patients with Recurrent Ventricular Tachycardia

Abstract

Introduction: Sustained Ventricular Tachycardia (VT) often occurs in the setting of structural heart disease and myocardial scar. Little is known about the prognostic value of endocardial scar or border zone after VT ablation. Methods 48 consecutive ICD patients with structural heart disease and documented VT underwent detailed endocardial voltage mapping (> 200 LV points). Endocardial scar and border zone were defined as < 0.5mV and 0.5-1.5 mV, respectively. Scar burden was defined as the ratio between endocardial scar and total left ventricular (LV) endocardial area, scar + border zone burden as the ratio between scar plus border area divided by LV area. Follow-up was included if ICD clinic notes or interrogations could be obtained at < 6 month intervals. VT recurrence (VTR) was defined as any VT >30s or causing appropriate ICD shocks. Mortality was determined using the Social Security Database. Results: All patients (46 male, age 62+12.18; 81% CAD; EF 26.39+12.47) underwent clinically indicated VT ablation with a mean follow-up of 31.5±8.7 months. A scar burden of >10% was associated with a higher rate of first VT recurrence (VTR) with 1.9, 1.5,and 1.2 fold increases seen at 12, 24 and 36 moths, respectively. Similarly, a scar+border zone burden of >25% resulted in 2.0, 1.6 and 1.2 fold increases of VTR at 12, 24 and 36 months, respectively. A scar burden of >10%was also associated with a 4.0, 3.7 and 3.9 fold increase in mortality at 12, 24 and 36 months, respectively. Similarly, a scar+border zone burden of >25% was associated with a 6.0, 3.8 and 3.8 fold increase in mortality at 12, 24 and 36 months, respectively. Conclusions: Large myocardial scar/border zone substrate correlates with earlier recurrence of VT and higher long-term mortality after VT ablation. This finding may allow for more refined risk stratification and guide an individualized pharmacologic/ablation-based approach to VT.