Rationale of Extracardiac Vagal Stimulation
The rationale for both ECVS and CNA is grounded in the distribution of
the cardiac autonomic nervous
system20,21,22.
Any medical procedure necessitates a method of control. Consequently, if
the procedure aims to achieve vagal denervation, it should monitor and
regulate the extent of this innervation and the elimination or reduction
of the vagal response19, Figure 2-C. Furthermore,
cardioinhibition typically involves a substantial bilateral vagal
response, and the control method must replicate it as closely as
possible. In clinical practice, the reproduction of cardioinhibition is
achieved through the HUTT, and in the laboratory, the sole method
capable of replicating a similar controlled condition is
ECVS10,19,23. Both
in spontaneous events and during the HUTT, there is a massive vagal
response simultaneously affecting all regions with vagal innervation,
particularly the sinus node, AV node, and atrial walls. This condition
can be readily reproduced with ECVS as many times as necessary,
depending on the operator, as illustrated in Figure 2-A and B. In this
method, the extensive vagal stimulation, accompanied by an overdrive of
the vagal efferent fibers, enables a clear, objective, and gradual
control of the degree of vagal denervation, ultimately leading to the
complete elimination of responses in the sinus node, AV node, and even
atrial walls19, Figure 2. Consequently, aside from
facilitating the rational conclusion of CNA, ECVS helps prevent
over-ablation. Therefore, the significance of ECVS, which is quite
intuitive from a rational standpoint, is statistically validated in this
study.