Mapping and ablation of ventricular arrhythmias with magnetic navigation: comparison between 4-and 8-mm catheter tips

Remote magnetic navigation (RMN) has been reported as an effective and safe tool to overcome the need for advanced operator skill in the treatment of complex arrhythmias. We report a series of patients undergoing radiofrequency catheter ablation of ventricular arrhythmias (VAs) using RMN with either a 4-mm catheter tip or an 8-mm catheter tip at four different centers. Sixty-five patients with clinical and symptomatic history of Vas were included. Two different magnetic catheters were used to deliver radiofrequency applications remotely. When ablation with the RMN catheters failed, a manual irrigated catheter was used to eliminate the VAs. Post-ablation pacing maneuvers were utilized to verify the inducibility of Vas. Twenty-eight patients (43%) had ischemic cardiomyopathy [coronary artery disease (CAD)], 16 patients (25%) had non-ischemic cardiomyopathy [idiopathic dilated cardiomyopathy (IDC)], and 21 patients (32%) had structurally normal hearts (SNH) or right ventricle outflow tract tachycardia (RVOT). In patients with structural heart disease (CAD, IDC), success was achieved in 22% with the 4-mm catheter tip and in 59% with the 8-mm catheter tip (p = 0.014). In patients with SNH/RVOT, success was achieved in 85% with the 4-mm catheter tip and in 87% with the 8-mm catheter tip (p = 1.00). Our findings showed that, with RMN, there is an increased success related to the catheter tip utilized. However, in patients with right ventricular outflow origin, the standard 4-mm tip provided adequate lesions for successful ablation in most patients.