Po-05-067 the use of the his bundle local activation time in outflow tract premature ventricular contractions to assist in localization

Localization of premature ventricular contractions (PVCs) from the outflow tract regions based upon ECG localization criteria may prove challenging based upon cardiac rotation and surface lead placement. Multiple studies describe ECG parameters based upon axis and precordial R wave transition for distinction of left (LVOT) vs right ventricular outflow tract (RVOT) site of origin. No previous studies describe intracardiac fiducial points to assist in site discrimination for PVC origin between LVOT, RVOT, and intramyocardial sites. Assessment of PVC timing at the His bundle region (HB) as a predictor for area of origin of a premature ventricular contraction. Timing at the area of the HB could help discriminate LVOT, RVOT, and intramural PVCs and guide ablation strategy. We performed retrospective analysis of 30 consecutive patients who underwent a PVC ablation from July 2021 until present day. During index mapping, placement of a multipolar catheter in the HB yielded local activation timing (LAT) for PVCs, and the HB was marked on the mapping system . The timing of a PVC was recorded as well as the area of successful ablation. Of the 30 patients 10 were female and 20 male with an average age of 60 years. The average EF was 52%. 10 patients had coronary artery disease 9 had ICDs. 10 Patients with successful LVOT ablation had HB LAT average of -6 msec +/- 12msec. 8 Patients with successful RVOT ablation had HB LAT average of 32 msec +/-11msec. 12 patients with successful intramyocardial ablation had HB LAT of 45 msec +- 8 msec. The difference between LVOT HB LAT and RVOT HB LAT was statically significant P<0.001. The difference between LVOT HB LAT and intramyocardial HB LAT was statistically significant P<0.001. The difference between RVOT HB LAT and intramyocardial HB LAT was statistically significant P<0.0062. Use of the HB as an intracardiac fiducial point for LAT assists with accurate localization and successful ablation of PVCs originating from the outflow tracts.