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).