Performance of surface electrocardiographic vectors in differentiating ventricular arrhythmia originating from coronary cusp, peri-pulmonic valve and right ventricular outflow tract

Abstract

Introduction: Symptomatic outflow tract ventricular arrhythmia (OTVA), including ventricular tachycardia and premature ventricular complexes, can be readily treated with catheter ablation. Outflow tract anatomy is complex and differentiating aortic, pulmonary and subvalvular origin is important for planning approach to mapping and ablation. We investigated whether surface ECG characteristics of OTVA can accurately discriminate between right coronary cusp (RCC), peri-pulmonic valve (PV) and right ventricular outflow tract (RVOT) origin. Methods: Thirty-six consecutive patients (mean age 41±14 years, 13 male) undergoing catheter ablation for OTVA were studied. Site of OTVA origin were determined from intracardiac electrogram tracings, electroanatomical maps and ablation reports. Observers blinded to these results manually measured PVC waveform amplitude and duration from standard 12-lead ECG tracings. Measurements with highest diagnostic performance were modelled into an algorithm designed to discriminate between predefined sites of origin within the outflow tract. Results: Sites of successful ablation were anterior RVOT (n=6), posterior RVOT (n=4), PV (≤1cm below, at or above pulmonary valve, n=18) and RCC (n=8). RCC origin was best discriminated by lead I R-wave ≥ 1.5 mV AND V1 R-wave ≥2.0mV (PPV 39%, NPV 94%, accuracy 67%). Posterior RVOT origin was best discriminated by lead I R/(R+S) ≥ 0.1 AND V1 R-wave > 0mV (PPV 33%, NPV 96%, accuracy 81%). Anterior RVOT origin was best discriminated by V1 R-wave = 0mV AND aVR/aVL S-wave ratio > 1 (PPV 100%, NPV 94%, accuracy 94%). Origin from PV was best discriminated by lead II/III R-wave ratio ≤0.95 OR lead I R/(R+S) < 0.08 (PPV 68%, NPV 86%, accuracy 75%). Sequential algorithmic application of these criteria resulted in an overall accuracy of 80% in predicting site of OTVA origin. Conclusions: Application of simple surface ECG criteria in sequential algorithmic fashion can discriminate between coronary cusp, peri-pulmonic and RVOT origin of outflow tract ventricular arrhythmia.