PO-05-073 CHARACTERISTICS OF BIPOLAR AND UNIPOLAR ELECTROGRAMS AT SUCCESSFUL ABLATION TARGETS FOR VENTRICULAR ARRHYTHMIA ORIGINATING FROM THE VICINITY OF LEFT VENTRICULAR SUMMIT

Abstract

Successful elimination of idiopathic ventricular arrhythmias from the vicinity of left ventricular summit could frequently be achieved from aortic cusps, endocardial or epicardial ablation. To explore whether the characteristics of bipolar and unipolar electrograms recorded from the vicinity of left ventricular summit could guide the appropriate site for successful ablation. Patients with idiopathic ventricular arrhythmias from the vicinity of left ventricular summit who underwent endocardial and epicardial mapping/ablation were retrospectively studied. Patients with structural heart disease or reentrant ventricular arrhythmias were excluded. Electrograms of the earliest activation sites in different anatomical structures, including great cardiac vein/anterior interventricular vein (GCV/AIV), supravalvular, subvalvular area, and/or right ventricular outflow tract (RVOT) were extracted for analysis. In total, 55 patients (median age 59 years, 42 men) and 163 mapping points were analyzed. These mapping points were located in GCV/AIV (n = 44), supravalvular area (n = 42), subvalvular area (n = 45), or the RVOT (n = 32). A pre-potential was identified at 17 (10.4%) points, while a unipolar QS morphology at 69 (42.3%) points. Successful ablation was achieved at 37 points. The presence of a pre-potential and the bipolar local activation time (LATBi) have a predictive value for successful ablation. In contrast, neither the unipolar LAT (LATUni), difference between LATBi and LATUni, presence of a unipolar QS morphology, nor the slope and interval of the unipolar descending limb could predict success. Earliest bipolar local activation and the presence of a pre-potential provide good surrogates to predict successful ablation of idiopathic ventricular arrhythmias originating from the vicinity of left ventricular summit.