The concept of area of lesion
Assessment of the extension of area of lesion following PVI has been the
target of several previous studies both after RF current applications,
cryoballoon ablation and laser therapy (2-4). The general notion is that
the use of balloon-based ablation treatments usually provides larger
area of lesion as compared to conventional point-by-point catheter
ablation. On the other hand, this could be challenged by others who
argue that also with the completion of WACA modality of ablation is
feasible the creation of a large antral lesion. In this regard, it
appears easier to promote uniform antral lesion through the
balloon-based ablation than that created by conventional point-by-point
RF applications, due to the potential occurrence of lesion gaps along
the line.
One could raise the question whether a large area of lesion is really
required for achieving an effective PVI. Looking at previous studies the
wide antral approach is more effective than ostial PVI in achieving
freedom from atrial tachyarrhythmia recurrence at long-term follow-up
(3). The other side of the coin of the creation of an extended antral
lesion is the chance to favor macro-reentrant atrial tachycardia with a
critical isthmus in the posterior wall of left atrium (5). Anyhow, the
searching of novel catheter design associated to specific energy sources
and their different modalities of delivering (unipolar vs bipolar,..etc)
should yield higher acute success rate and better clinical outcome. In
this study, My et al. have selected two different energy sources coupled
with two novel catheter designs and compared their effects on the
extension of lesion and they found that PFA creates larger acute lesion
areas (20.7 ± 7.7 cm2) than RF balloon-based ablation (7.1 ± 2.09 cm2; p
< 0.001). Is this finding so crucial to support the hypothesis
that larger antral lesion facilitates a better clinical outcome? Of
course, there is no definite answer, due to the limited number of
patients included and the lack of data over the follow up. We might
anticipate that having a larger area of lesion could be more beneficial
for persistent AF than paroxysmal, due to the critical role played by
the posterior left atrial wall in the maintenance of AF.