5.2 Irrigation system
Local temperature elevation at the distal tip of ablation catheter during RFCA can result in temperature-dependent coagulum and char formation.9 Histological review of these deposits revealed that it was consisted of denaturized and aggregated proteins rather than classical thrombus.9 Therefore, reducing the temperature of distal electrode tip can potentially reduce char and thrombus formation.
In our registry, patients who were ablated with non-irrigation catheters showed highest risk of having procedure-related ischemic complication (1.72%) followed by non-slit-based irrigation (0.71%) and slit-based irrigation catheters (0.08%). Irrigation catheters were developed for two major reasons: formation of deeper lesions and reduction of ischemic complications.10Previous studies demonstrated that irrigation catheters were capable of making deeper lesions as compared with non-irrigation catheters.16, 17 Although irrigation catheters have shown that coagulum formation can be reduced as compared to non-irrigation catheters, whether irrigation catheters can reduce clinical ischemic complications remains largely unknown.10
Previous study reported that irrigated tip catheter did not reduce the incidence of symptomatic peri-procedural ischemic stroke.18 However, the study enrolled patients from February 2001 to January 2008 where no slit-based irrigation catheters were available and our study demonstrated a lower incidence of procedure-related ischemic complication in slit-based irrigation catheters. Our study also showed lower incidence of procedure-related ischemic complication in non-slit-based irrigation catheters compared non-irrigation catheters (0.71% vs. 1.72%). The discrepancy between the two studies can be due to small sample size or different type of non-irrigation catheter (predominantly 8mm tip in the study by Scherr et al. and 4mm tip in ours).