Electrophysiological Parameters of Vagal Denervation
In this study, both groups exhibited significant electrophysiological
changes in all parameters related to the vagal effect. There was a
notable increase in sinus rate and the Wenckebach point, along with a
reduction in sinus node recovery time, sinoatrial conduction time, and
AV refractory period. All other parameters unrelated to the vagus showed
no significant changes, as detailed in Table 2 and Table 3.
The original CNA study we had no ECVS3. Ablations were
directed towards areas with the highest density of AF-Nests, typically
associated with the neuro-atrial interface in normal
heart3,19,24,25. Additionally, extended ablations were applied to
anatomical regions that presumably overlapped with the primary GPs,
which also tend to harbor a higher number of AF-Nests. The goal was to
achieve sufficient depth for epicardial GP ablation. In cases with a
high risk of esophageal thermal injury, mechanical esophageal
displacement was performed using a transesophageal echocardiogram
transducer. Based on the initial CNA technique, relying on spectral
mapping obtained through online spectral analysis26,
we developed the Fractionation Mapping, making the innervation tracking
easier and faster27, Figure 5.
Figure
5
While the ablated points appeared adequate, the depth of thermal effect
on the atrial wall and epicardium, and consequently the extent of
denervation, could not be measured. The increase in sinus rate and the
Wenckebach point, along with the shortening of the AH and EAVRP, serve
as important indicators of denervation (as detailed in Table 2 and Table
3); however they represent indirect parameters and do not necessarily
indicate a full effect. Immediate results may be achieved by eliminating
superficial fibers, but long-term outcomes depend on the disappearance
of deep neural bodies. There are numerous instances where, despite
modifications in all EP parameters, ECVS reveals a significant residual
vagal response28, often leading to clinical
recurrence. In this study, we found that although there was no
statistically significant difference in the electrophysiological
parameters of acute vagal denervation (as shown in Table 3), there was a
significant difference in long-term outcomes, suggesting that immediate
electrophysiological response alone may not be enough to predict the
long-term efficacy of CNA.