Gastric slow-wave modulation via power-controlled, irrigated radio-frequency ablation.

Background: Recently, radio-frequency ablation has been used to modulate slow-wave activity in the porcine stomach. Gastric ablation is, however, still in its infancy compared to its history in the cardiac field, and electrophysiological studies have been restricted to temperature-controlled, non-irrigated ablation. Power-controlled, irrigated ablation may improve lesion formation at lower catheter-tip temperatures that produce the desired localized conduction block.

Methods and results: Power-controlled, irrigated radio-frequency ablation was performed on the gastric serosal surface of female weaner pigs (n = 5) in vivo. Three combinations of power (10-15 W) and irrigation settings (2-5 mL min^-1) were investigated. A total of 12 linear lesions were created (n = 4 for each combination). Slow waves were recorded before and after ablation using high-resolution electrical mapping.

Key results: Irrigation maintained catheter-tip temperature below 50°C. Ablation induced a complete conduction block in 8/12 cases (4/4 for 10 W at 2 mL min^-1, 1/4 for 10 W at 5 mL min^-1, 3/4 for 15 W at 5 mL min^-1). Blocks were characterized by a decrease in signal amplitude at the lesion site, along with changes in slow-wave propagation patterns, where slow waves terminated at and/or rotated around the edge of the lesion.

Conclusions and inferences: Power-controlled, irrigated ablation can successfully modulate gastric slow-wave activity at a reduced catheter-tip temperature compared to temperature-controlled, non-irrigated ablation. Reducing the irrigation rate is more effective than increasing power for blocking slow-wave activity. These benefits suggest that irrigated ablation is a suitable option for further translation into a clinical intervention for gastric electrophysiology disorders.