Electrocardiographic Predictors Of Outcome After Radiofrequency Catheter Ablation Of Ventricular Outflow Tract Premature Ventricular Complexes

Objectives To assess the efficacy of radiofrequency catheter ablation in patients with outflow tract ventricular premature complexes,and to explore the electrocardiographic features of initially successful procedures.Methods 154 consecutive patients with outflow tract ventricular premature complexes who underwent catheter radiofrequency ablation from January 2017 to December 2019 were divided into two groups according to the outcome of ablation.Assess the rate of succesful procedures and the ECG features were analyzed and compared between the two groups.Results 1.A total of 154 patients were initially considered in this study,including136 patients(88.3%)with initially successful procedures and 18 patients with failed ablation.8 patients(5.9%)after initially successful ablation had recurrence during the follow-up period,and 7 recurrent cases received secondary catheter radiofrequency ablation with success rate of 100%.Among the 154 patients,1 patient had ventricular fibrillation during ablation,which could be transferred to the sinus rhythm after electrical defibrillation,2 patients had prolonged P-R interval after ablation,and no other acute or long-term complications were observed.2.The highest success rate was in patients with ventricular premature complexes from the RVOT,and the lowest success rate was in patients with both from RVOT and LVOT,while there were no significant differences regarding gender,age,course,symptomatic status,the history of drinking,hypertension,diabetes,LVEF,LVEDD,LVESD,E/E’,E/A,as well as multiple sources of premature ventricular beats.3.The 136 patients with successful procedures had lower ratio of existence of pseudoΔwave(16.2% vs 44.4%,P < 0.01),smaller R wave amplitude in V1(0.23±0.24 m V vs 0.35±0.44 m V,P<0.05),shorter IDT in V2(44.00±18.33 ms vs 57.41±20.67 ms,P<0.01),shorter RS duration in V2(93.67±21.33 ms vs 106.93±18.76 ms,P<0.01),and smaller R/S ratio in V2(0.21±0.32 vs 0.37±0.90,P<0.05).4.Multivariate analysis demonstrated that RS duration and R/S ratio in V2 predict failed procedure,and based on the ROC curve analysis,the cut-off values for RS duration in V2>109.17 ms,R/S ratio in V2>0.28 predict failed ablation(sensitivity=50% and specificity=86.8%,sensitivity=72.2% and specificity=62.5%,respectively).Conclusions The efficacy and safety of catheter radiofrequency ablation for outflow tract ventricular premature complexes have been described in the study.The electrocardiographic predictors of failed ablation were characterized by RS duration and R/S ratio in V2,and RS duration in V2>109.17 ms or R/S ratio in V2>0.28 was associated with a lower rate of succesful ablation.