Catheter ablation approach for DGCV-AIV VAs
Previous studies have revealed that one key point for successful
ablation of DGCV-AIV VAs is the structure of DGCV-AIV being sufficiently
accessed and mapped. However, the existence of anatomic obstacles in the
coronary venous system limited the ablation catheter manipulation and
access to the target sites in this region. In some cases, even advancing
the ablation catheter to the proximal GCV is difficult. In our study,
due to the obstacle of venous valves, catherter tip could not reach the
proximal-middle GCV by NS approach and SS approach in 6 patients. One
study reported in one patient with DGCV VAs, because of the tortuous
course of GCV, catheter ablation could not access the optimal target
site of VAs[8]. Contact force catheter guided deep
engagement with a steerable sheath
in the DGCV was then performed. The contact force catheter and steerable
sheath were advanced alternately, which overcame the deflections in GCV
and resulted in the deep engagement of catheter tip to DGCV and
successful ablation of DGCV VAs. However, this method had its
limitations. In patients with small size coronary venous system, it
could be challenging to manipulate the contact force catheter and
steerable sheath, as both of which were much larger than the
conventional irrigated catheter and sheath in diameter. Besides, the
much harder characteristics of steerable sheath may more easily cause
coronary vein dissection and rupture. Another study also reported
anatomic obstacles restrained successful ablation of DGCV-AIV VAs[7]. Due to the very distal portion of DGCV are
usually very thin and frequently inaccessible to an ablation catheter,
Kazutaka A et al. delivered a 2F microcatheter into the vein as a
landmark of the ablation sites and performed ablation in the nearby
endocardial structures. However, by this approach, the elimination of
these VAs usually requires ablation at multiple sites at adjacent
structures and because of indirect ablation, the efficacy of RFCA was
usually limited. In our research, we found that an aute angle between
AIV and DGCV was also another anatomic obstacle difficult to overcome
when cathter ablation was performed, for which, an appropriate
manipulation approach remained investigated. In addition, we found in a
situation of narrow elliptical shape of CVS
(Width/Height>0.69), SS approach ensured a powerful backup
force for ablation catheter, which could assist catheter tip overcome a
partial anatomic impediments of coronary venous system and
reach the target sites in DGCV-AIV
more easily, contributed to a relative higher success rate of RFCA.
Thus, it was more favorable than NS approach when RFCA of DGCV-AIV VAs.
It should be noted that when catheter ablation of DGCV-AIV VAs, anatomic
obstacle is not the the only factor that limits successful ablation. In
clinical practice, successful ablation of DGCV-AIV VAs is associated
with a network of factors, including origin sites (epicardially or
intramurally), distance to adjacent coronary artery, impedance during
ablation and so on.