One-Stage Versus Sequential Hybrid Radiofrequency Ablation: An In Vitro Evaluation

Objective: To compare lesion size and depth between a I-step, a sequential, and a delayed radio-frequency ablation in a hybrid setup. Methods: Left atrium tissues obtained from fresh porcine hearts were mounted into the ABLABOX simulator. Based on the time differences between the index epicardial (epi) and consequent endocardial (endo) ablation, 3 study groups were compared: a I-stage (SEQ- 0) group (0-minute delay), an SEQ I group (60-minute delay), and an SEQ 2 group (240-minute delay). During the experiment, a constant epicardial (300 gr) and endocardial (30 gr) force were applied. Per group, 20 samples were studied, and the resulting lesion size and depth were quantified with morphometric evaluation. Results: Overall, no transmural lesion was obtained. Lesions in SEQ 0 had better maximum and minimum diameters (P < 0.001), a larger total area (P < 0.001), and volume (P < 0.001) than SEQ 1 and SEQ 2. There was no statistical difference in morphometric parameters (all, P > 0.05) between the delayed procedures (SEQ 1 and SEQ 2). Conclusions: In our in vitro model, different time sequences of combined epi-endo ablation did not result in transmural lesions. However, simultaneous epi-endo ablation produced broader and deeper lesions. Our findings need to be confirmed by further research.