P504VT ablation outcomes and predictors in a UK population- validating existing predictors and novel markers

Abstract Background Radiofrequency catheter ablation (CA) can reduce ventricular tachycardia (VT) burden and registry data suggests an improvement in mortality. However, there is significant heterogeneity in patient morbidity and VT phenotype. A risk prediction model derived from observational data has suggested pre-procedural left ventricular (LV) function, age and underlying ischaemic cardiomyopathy are associated with greater post-procedural mortality. Validation of proposed factors in clinical practice is required to facilitate comprehensive pre-procedural risk stratification and inform decision making. Purpose To determine whether proposed pre-procedural predictors of mortality after VTCA are valid in a UK population and explore any association with other predictors. Method Patients undergoing VTCA at a tertiary electrophysiology centre between 06/07/16 and 31/07/19 were included. Pre-specified characteristics and mortality follow-up data were analysed from electronic health records. Cox regression analysis was undertaken to determine association with mortality. Results 161 patients with mean age of 63 ±15.9 years underwent VTCA of whom 133 (83%) were male. During the follow-up period (16 months, 13-24; median, 1st-3rd quartile) 16 patients died. No deaths occured in the 27 (16%) patients with structurally normal hearts. Chronic kidney disease (CKD) stage III-IV (HR 14.73 [4.9-44.4]), LV ejection fraction <35% (HR 7.13 [1.59-31.88]), underlying ischaemic cardiomyopathy (HR 6.17 [1.37-27.85]), LV internal diameter (LVID) (1.08 [1.02-1.15]) and age (HR 1.08 [1.02-1.14]) were associated with significantly greater mortality risk (Table 1) (Figure 1). Conclusion Proposed risk stratifying factors are validated in our UK centre’s experience. Additionally, CKD and baseline LVID appear to be associated with mortality in our population and warrant further study. Risk factor Hazard ratio Lower confidence interval Upper confidence interval P-value Atrial fibrillation (yes/no) 0.14 0.02 1.11 0.06 Age (years) 1.08 1.02 1.14 <0.01 Diabetes (yes/no) 2.43 0.85 6.92 0.10 Chronic kidney disease (yes/no) 14.73 4.88 44.41 <0.01 Ischaemic cardiomyopathy (yes/no) 6.17 1.37 27.85 0.02 LV EF <35% (yes/no) 7.13 1.59 31.88 <0.01 LV internal diameter (mm) 1.08 1.02 1.15 <0.01 Procedural urgency (urgent/elective) 1.12 0.57 2.20 0.75 Table 1: Association between baseline risk factors and mortality risk after VT catheter ablation Abstract Figure 1: Kaplan-Meier survival curves