Introduction: It often is difficult to determine the optimal ablation site for idiopathic ventricular tachycardia (VT) originating from the right ventricular outflow tract (RVOT) when the VT or premature ventricular complex (PVC) does not occur frequently. The aim of our study was to evaluate the usefulness of a multielectrode basket catheter for ablation of idiopathic VT originating from the RVOT.
Methods and results: Radiofrequency (RF) catheter ablation was performed using a 4-mm tip, quadripolar catheter in 50 consecutive patients with 81 VTs originating from the RVOT with (basket group = 25 patients with 45 VTs) or without (control group = 25 patients with 36 VTs) predeployment of a multielectrode basket catheter composed of 64 electrodes. Deployment of the multielectrode basket catheter was possible and safe in all 25 patients in the basket group. Ablation was successful in 25 (100%) of 25 patients in the basket group and in 22 (88%) of 25 patients in the control group. The total number of RF applications and the number of RF applications per PVC morphology did not differ between the two groups. However, both the fluoroscopic and ablation procedure times per PVC morphology were shorter in the basket group than in the control group (36.8+/-14.1 min vs 52.0+/-32.5 min, P = 0.04; 60.0+/-14.6 vs 81.5+/-51.2 min, P = 0.05). This difference was more pronounced in the 29 patients in whom VT or PVC was not frequently observed.
Conclusion: The multielectrode basket catheter is safe and useful for determining the optimal ablation site in patients with idiopathic VT originating from the RVOT, especially in those without frequent VT or PVC.