Differentiating Left From Right Ventricular Outflow Tract Arrhythmia Origins Using QRS-HIS Interval

Objective The aim of this study was to assess the value of QRS-VHIS interval and QRS-VRVA interval on differentiating the origin of idiopathic outflow tract ventricular arrhythmias.Methods Sixteen patients underwent radiofrequency ablation were enrolled.The two mapping catheters were located in the region of His and right ventricular apex(RVA)during the procedure.Routine electrophysiological study and radiofrequency ablation were performed,multisite ventricular pacing were also conducted in all patients with 12-lead electrocardiogram and HIS/RVA intracardiac electrogram recorded in each pacing site.We measured the interval from the onset of the earliest QRS complex of pacing to the first peak of V wave recorded in the His catheter (the QRS-VHIS interval)and the interval from the onset of the earliest QRS complex of pacing to the first peak of V wave recorded in the RVA catheter(the QRS-VRVA interval)respectively.Results A total of 139 data were obtained from multisite pacing of 16 patients,then the data were divided into RVOT group(n=94)and ASC group(n=45)according to the pacing site.The QRS-VHIS intervals were significantly greater in the ROVT group compared with that in the ASC group(42.98 ± 14.83 vs 19.66 ± 16.14,p<0.001).The ROC curve analysis showed that the AUC of QRS-VHIS was 0.860 which was superior to that of the previous reported QRS-VRVA interval(AUC=0.626).The QRS-VHIS interval≤36.4ms predicted an ASC origin with 67.1%sensitivity and 85%specificity which was better than that of QRS-VRVA interval with 54.3%and 72%respectively.Conclusion The QRS-VHIS interval could be used as a new approach to identify the origin of idiopathic outflow tract ventricular premature contractions.