Abstract 18650: Activation Mapping of Ventricular Ectopy: Characterization of a Threshold Value Predicting Successful Catheter Ablation

Abstract

Background: Catheter ablation of ventricular ectopy is performed with increasing frequency. Activation mapping to determine the site with the earliest presystolic electrogram (EGM) is the most accurate method to locate the optimal ablation site. Despite this, activation mapping of ventricular ectopy has not been systematically reviewed in a large series, and the optimal activation time predicting successful ablation has not previously been determined. The goal of this study is to determine the local presystolic activation time most predictive of successful ablation. Methods and Results: We retrospectively reviewed 100 consecutive successful endocardial PVC ablations and analyzed the local activation time at each successful and unsuccessful ablation site. A total of 561 ablation lesions were reviewed. Activation time was calculated as the difference between the peak of the local bipolar EGM and the onset of the reference surface QRS complex. Acute success was defined as complete elimination of the target PVC during the procedure with no recurrence at 30 days by ECG and follow-up Holter. A local activation time 27 msec presystolic best predicted success with a sensitivity of 88%, specificity 85%, and an area under the ROC curve of 0.936 (95% CI 0.91 - 0.95; figure 1). The 27 msec presystolic activation time remained most predictive of success after sub-stratifying activation times by location (RVOT v LVOT, outflow v intracavitary). The odds ratio for success with each 1 msec increase in activation time (becomes more negative by 1 msec) is 1.24 (95% CI 1.19 - 1.29). Conclusion: In our experience, a local presystolic activation time of 27 msec is the threshold value most predictive of successful PVC ablation. Our review is the first to systematically characterize an activation time predicting success with PVC ablation in a large cohort. Figure 1