Discussion
To our knowledge, this is the first study to compare the different
radiofrequency ablation catheters in AVN ablation. Patients were elderly
with multiple comorbidities. The procedure was highly successful with no
immediate complications. HPSD catheter was significantly shorter
compared with the plain catheter.
The main current indication for AVN ablation is atrial tachyarrhythmias
that are resistant to other treatment modalities, especially in the
elderly population(16, 17). Two large trials assess the role of AVN
ablation in resistant atrial tachycardia. In the ablate and pace trial,
156 with resistant atrial fibrillation had AVN ablation with permanent
pacemaker placement. After the procedure, patients had improved quality
of life and improved left ventricular function (18). In patients with
heart failure and symptomatic AF, AVN ablation with cardiac
resynchronization (CRT) reduced HF-related hospitalization and improved
quality of life(19). As in previous research, our population was elderly
with several comorbidities. The indication was atrial tachyarrhythmia
resistant to medical therapy, mainly atrial fibrillation(74%). We
assessed the short-term effectiveness of the procedure with no data on
long-term effects.
The procedure is typically highly successful with a low complication
rate. The overall success rate is above 97%(16). In our study, all
procedures were successful with no immediate complications. We could not
assess for factors associated with procedure success/failure as we had
no failed ablation.
Ablation catheters have advanced in the design to improve safety and
effectiveness. Several new catheters were introduced, including
irrigated and contact force catheters. Several studies and systemic
reviews compared the safety/effectiveness of different catheters in
atrial fibrillation ablation(20-22). Studies in atrial fibrillation
favored HFSD in success rate and procedure time(23-25). Direct current
energy was used in the early stages but was soon replaced by
radiofrequency due to better safety and effectiveness (16). Few/no
studies compared different radiofrequency ablation catheters in AVN
ablation. In our study, a contact force catheter with HPSD settings was
significantly associated with lower lesion time by 403.42s[-631.67,
-175.17]. The success rate was similar to other catheters(all
successful) with no immediate complications.
Current medical practice has increasing complexity with introducing new
management modalities. Comparative effectiveness research is essential
to improve the quality of care and guide policymakers, clinicians, and
patients in deciding on their care(26). Our study has several
limitations. First, procedures were done by different operators, which
could confound our results. Differences in lesion time could be related
to different expertise levels between different operators. Another
limitation was the short follow-up time. There were no immediate
post-procedure complications. However, no data regarding long-term
safety and efficacy were available. We had no data regarding long-term
patient outcomes such as morbidity, mortality, and quality of life.
Complications are likely to occur in the immediate post-procedure time;
as a result, we likely to document the severe complications that would
happen. The main aim of the study was to compare different
radiofrequency ablation catheters. Data regarding the long-term effect
of AVN ablation is needed; however, that was not the focus of our
research. It is unlikely that the long-term effects would be related to
the type of catheter used.