A Novel Bipolar Radiofrequency Clamp for Efficient Isolation of the Left Atrial Posterior Wall

Objective: We evaluated a novel radiofrequency (RF) clamp that enables isolation of the entire left atrial posterior wall (LAPW) with a single application and was designed to reduce ablation time without sacrificing efficacy. Methods: Six Yorkshire pigs (47 ± 4 kg) underwent median sternotomy. A dual-generator RF clamp was used to create a lesion that isolated the LAPW with a single application. An additional lesion was created to isolate the left atrial appendage (LAA). Exit block testing was performed for all lesions. Hearts were perfused with triphenyl tetrazolium chloride (TTC), arrested, and explanted, and lesions were transversely sectioned at 5 mm intervals. Lesion transmurality was assessed with TTC staining and confirmed on histology when necessary. Ablation time and delivered energy were determined and compared with those from the previously tested single-generator version of this device. Results: Surgical ablation was successfully performed on all 6 animals. A total of 12 lesions, 6 LAPW and 6 LAA, were created, corresponding to 297 histological sections. Exit block was uniformly demonstrated (12 of 12). Transmurality was achieved in 100% of cross sections (297 of 297). LAPW ablation time was 37.9 ± 9.1 s, a 48% reduction compared with the single-generator clamp (72.5 ± 7.5 s, P < 0.001). The total energy delivered was 1,109 ± 343 J, similar to that of the single-generator clamp (1,231 ± 138 J, P = 0.45). Conclusions: The dual-generator, split-electrode RF clamp created transmural lesions with a single application while nearly halving ablation time compared with the previous single-generator clamp.