AV nodal modulation and ablation: better at a distance from the
node?
To the editor,
We have read with great interest the manuscript by Lisa Lemke et al,
entitled ”AV-node isolation as an alternative to AV-node ablation in
patients undergoing pace & ablate strategy”(1).
We agree in that the idea of preserving an atrio-ventricular nodal (AVN)
escape rhythm after AVN ablation resulting in complete block is of
interest.
We appreciate that the methodology used with the semicircular ablation
line connecting the superior and inferior aspects of the tricuspid valve
fibrotic ring is somewhat similar to that recently proposed by our group
for AVN conduction modulation (2), in which an initial successful AVN
modulation occurred in 88% of patients, and no case of persistent
high-degree AVN block was observed (transient atrioventricular block in
12%). In this study, the procedures were performed during sinus rhythm
and electroanatomical activation mapping of the right atrium was
performed during ventricular stimulation to identify the right atrial
breakthrough (presumably the main atrial insertion of the AVN), with
radiofrequency applications always maintaining a distance of at least
0.5 cm from it.
In the study by Lisa Lemke et al, another reference is used for the
ablation line, sites with His signals (His cloud) and the distance to
these signals is not specified. The figures presented in the manuscript
show that applications were performed at a short distance to the ”His
cloud” (1). We observed that the mean distance between the atrial
breakthrough and the His bundle electrogram was 0.62 cm but this was
highly variable (0.36 – 1.4 cm) (2).
It would be very interesting to know if, before achieving complete
block, a progressive decrease in heart rate (or an increase in
atrioventricular block cycle length in those patients who were in sinus
rhythm during the procedure) occurred. Likewise, to know if there was a
progressive prolongation of the PR interval. All of these would be data
suggesting modulation prior to AV ablation.
New therapeutic possibilities open up in the nonpharmacological rate
control of patients with atrial fibrillation, and an approach with an
ablation line around the AVN could be useful both for modulating the
ventricular response and for safer AV ablation if this is finally
required.
Lemke L, El Hamriti M, Braun M, Baridwan N, Sciacca V, Fink T, Khalaph
M, Guckel D, Eitz T, Sohns C, Sommer P, Imnadze G. AV-node isolation
as an alternative to AV-node ablation in patients undergoing pace &
ablate strategy. J Cardiovasc Electrophysiol. 2022 Oct 11. doi:
10.1111/jce.15699. Epub ahead of print. PMID: 36218022.
Ibáñez Criado JL, Ibáñez Criado A, Barrio-López T, Brouzet T,
Castellanos E, Ortiz M, Sánchez-Quiñones J, Garcia-Fernández A,
Ramos-Ruiz P, Heras S, Ajo Ferrer R, Ajo Ferrer M, Rico M, Quiles JA,
Sogorb-Garri F, Martínez Martínez JG, Almendral J. New Approach for
Atrioventricular Conduction Modulation by Ablation at a Distance From
the Atrioventricular Node: Role in Nonpharmacologic Rate Control of
Atrial Tachyarrhythmias. Circ Arrhythm Electrophysiol. 2021
Apr;14(4):e009550. doi: 10.1161/CIRCEP.120.009550. Epub 2021 Apr 16.
PMID: 33858181.