Low flow, high power, short ablation duration: Is this the key to avoid collateral damage?

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Background: In the era of force-sensing catheter technology, there is concern about increasing rates of collateral injury during AF ablation of the thin posterior left atrial wall. Simply reducing ablation power may not be the best strategy. Objective: We hypothesized that radiofrequency (RF) ablation at high power and short duration will achieve similar results to low power and long duration and that high irrigation flow may reduce ablation efficacy in thin walled tissues. Methods: Fresh killed porcine ventricles (N=13) were superfused with 0.45% NaCl at 37°C. RF ablation was performed with a 4 mm catheter with contact force of 20 gmforce. Fixed delivered power was varied from 20-50 W, ablation time from 5-40 sec, and irrigation flow of 2 or 17 ml/min. Lesion dimensions including depth, maximum width, and surface width were recorded. Results: The data for 165 lesions is shown (fig). Lesion depth increased inverse-exponentially over time for all powers (left, similar data for 2 and 17 ml/min flow rates). The ablation time required to achieve 4 mm lesion depth decreased with increasing power (right). At all powers, high flow rates (17 ml/ min) resulted in smaller surface lesion widths than low flow rates (2ml/min) with an average decrease of 9.9%, but lesion depth was only 1.8% deeper.

Conclusion: Effective lesions can be performed with high power and short ablation durations, which could effectively reduce the time of RF ablation procedures and concentrate the heating to superficial depths potentially reducing collateral injury. Wider surface lesions can be achieved with low irrigation flow with similar depth when compared to high irrigation flow, resulting in more contiguous lesions.


Heart Rhythm Society Scientific Sessions, Chicago, IL, May 12, 2017.