Deep Foci RF ablation using 3830 Medtronic pacemaker lead: proof of concept

Introduction Radiofrequency (RF) is the preferred thermal energy used in electrophysiology. RF catheter must deliver the energy close to arrhythmia foci. A new method to deliver RF to deeper locations using a pacemaker lead is explored. Methods A Medtronic 3830 lead screwed in chicken breasts delivered 50 watts RF energy in three methods: A) direct fashion (RF catheter touching the proximal end of the 3830 lead, acting as an extension of RF catheter), or B) 3830 lead as a return patch (RF delivered in the bath without contact), or C) 3830 lead as a return patch (RF delivered touching the breast surface close to the 3830 lead screwed deep in the flesh). Different power settings were also tested. Lesion surface area is reported in cm2. Results 76 measurements were available. Bigger lesions were obtained at 10W method A (0.78cm2), 50W method C (0.72cm2) and 5W method B (0.44cm2). High impedances were noted at 10W and 50W with tissue remaining attached to the lead when removed. Conclusion RF can be delivered to deeper foci through a 3830-pacemaker lead with maximum size lesion formation using proximal unipolar direct delivery and proximal close bipolar as the return patch. In humans, it opens a path to attain deep septal foci (LV summit) or epicardial structures (vein of Marshall, transmural ablation from RF endocardial to LV coronary sinus lead as return patch): using standard, 4F pacemaker leads, and 2F small EP catheters or even isolated guidewires.