Radiofrequency Ablation vs. Antiarrhythmic Medication for Treatment of Ventricular Premature Beats From the Right Ventricular Outflow Tract: A Prospective Randomized Study
What is the efficacy of radiofrequency catheter ablation (RFCA) versus antiarrhythmic drugs (AADs) for treatment of patients with frequent ventricular premature beats (VPBs) originating from the right ventricular outflow tract (RVOT)?
A total of 330 eligible patients were included in the study, and were randomly assigned to RFCA or AADs (open-label metoprolol or propafenone). The absolute number and the burden of VPBs on 12-lead Holter monitors were measured at baseline, and 1st, 3rd, 6th, and 12th months after randomization. Left ventricular ejection fraction (LVEF) was evaluated by transthoracic echocardiogram at baseline and at 3 and 6 months following randomization.
During the 1-year follow-up period, VPB recurrence was significantly lower in patients randomized to the RFCA group (32 patients, 19.4%), versus the AADs group (146 patients, 88.6%; p < 0.001, log-rank test). In a Poisson generalized estimating equations (GEEs) regression model, RFCA was associated a greater decrease in the burden of VPBs (relative risk, 0.105; 95% confidence interval [CI], 0.104-0.105; p < 0.001) compared to AADs. In a liner GEE model, the LVEF had a tendency to increase after the treatment in both groups (coefficient, 0.584; 95% CI, 0.467-0.702; p < 0.001). In a Cox proportional model, the QS morphology in lead I was the only predictor of VPB recurrence free for catheter ablation (hazard ratio, 0.154; 95% CI, 0.044-0.543; p = 0.004).
The authors concluded that catheter ablation is more efficacious than AADs for preventing VPB recurrence in patients with frequent VPBs originating from the RVOT. Also, QS morphology in lead I was associated with better outcome after ablation.
Despite rapid advances in VPB ablation, surprisingly there have not been randomized studies comparing its efficacy against AADs. This study has confirmed what has been clinically appreciated without randomized clinical data—higher efficacy of catheter ablation over AAD. Interestingly, only three patients in this series underwent activation mapping with a three-dimensional mapping system, which greatly facilitates mapping over the fluoroscopic only approach. This may potentially explain lower observed efficacy of the ablation of VPBs with a non-QS morphology in lead I.
Keywords: Ventricular Function, Left, Electrophysiologic Techniques, Cardiac, Cost of Illness, Drosophila Proteins, Tachycardia, Ventricular, Propafenone, Stroke Volume, Confidence Intervals, Metoprolol, Ventricular Premature Complexes, Catheter Ablation
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