Abstract 9966: Assessment of Wavefront Activation Duration Across the Right Ventricular Outflow Tract in Patients with Idiopathic Premature Ventricular Contractions Using Non Invasive Electrocardiographic Mapping: A Validation Study

Abstract

Introduction: Previous studies have reported that activation speed across the right ventricular outflow tract (RVOT) can distinguish premature ventricular contractions (PVCs) with a RVOT origin from PVCs with a left ventricular outflow tract (LVOT) origin. Hypothesis: Validate the non-invasive electrocardiographic mapping (ECGI) for assessment of RVOT endocardial activation duration (AD) during PVCs and assess the value of AD as a predictor of the origin of the PVCs. Methods: We studied 15 consecutive patients, 8 males, median age 56 (42-65) years that underwent ablation of frequent (> 10.000 per 24 h) idiopathic PVCs with inferior axis and had an ECGI performed before ablation. The ECGI was performed with the Amycard system, and all ablations were done with Stereotaxis and Carto system. Isochronal activation maps of the PVCs were obtained with the activation direction method (ADM) of the ECGI, and with the Carto isochronal activation map (10 ms isochrones). Total RVOT AD was measured as the time interval between the earliest and the latest activated region. Agreement between the two methods was performed using linear regression and Bland-Altman plot. The cutoff value of AD to predict PVC origin was calculated with ROC curve. Results: PVCs originated from the RVOT in 9 (60%) patients. The median (Q 1 -Q 3 ) RVOT AD measured with ECGI was 50 (36-70) and with Carto 50 (37-72) ms. The agreement between both methods was good with an R 2 of 0.699, p<0.0001, Bland-Altman plot in figure, and example of the same patient measured with Carto and ECGI. The AD was significantly higher in PVCs from the RVOT vs LVOT, both with ECGI and Carto, respectively 67 (54-74) vs 36 (33-40) ms, p<0.0001 and 68 (57-77) vs 35 (30-41) ms, p<0.0001. The cutoff value of 43 ms for AD measured with ECGI predicted the origin of the PVCs with a sensitivity and specificity of 100%. Conclusions: We found good agreement between ECGI and Carto. The AD obtained with ECGI was accurate to predict the origin of the PVCs.