Initial clinical experience with a novel visualization and virtual electrode radiofrequency ablation catheter to treat atrial flutter

Background: Linear ablation lesions are used to treat a variety of cardiac arrhythmias. However, successful long-term outcome is hampered by both the uncertainty of catheter-tissue contact for any individual lesion and the difficulty in ensuring point-to-point lesion contiguity.

Objective: A novel virtual electrode radiofrequency ablation catheter equipped with an endoscope to directly visualize the target tissue was used to ensure tissue contact and lesion contiguity along the cavotricuspid isthmus (CTI) to treat typical atrial flutter.

Methods: In this feasibility study of five patients with drug-resistant CTI-dependent atrial flutter, catheter ablation was performed using the visualization virtual electrode radiofrequency ablation catheter. After standard femoral access, the ablation catheter was advanced to the tricuspid annulus under fluoroscopic and intracardiac echocardiography guidance. In three of five patients, the ablation procedure was performed during atrial flutter; the other two ablations were during coronary sinus pacing.

Results: Conversion to sinus rhythm was noted after the delivery of 12 ± 7 lesions. Bidirectional CTI conduction block was successfully achieved in all patients. Initial, transient CTI block was first observed after delivering 19 ± 13 lesions; ultimately, 34 ± 18 lesions were required to achieve permanent bidirectional CTI block. The mean ablation and procedure times were 72 ± 42 and 151 ± 17 minutes. The mean fluoroscopy times for the ablation alone and the entire procedure were 13 ± 8 and 17 ± 7 minutes, respectively.

Conclusions: This study introduces the clinical feasibility of a novel paradigm for contiguous linear ablation: virtual electrode ablation under direct endoscopic visualization.