Conclusion
The MPL was far away from the esophagus with thicker myocardium tissue
and more fat pad than the CPL; thus, MPL could serve as a favorable
alternative in linear ablation for LAPW isolation.
Keywords: Catheter ablation – atrial fibrillation, Enhanced
multidetector computed tomography (CT), Left atrial posterior wall
(LAPW) isolation, Modified posterior-inferior line (MPL), Conventional
posterior line (CPL)
1 INTRODUCTION
Pulmonary
vein (PV) isolation has been considered as the cornerstone for catheter
ablation in the treatment of atrial fibrillation
(AF).1,
2 However, the ablation of persistent AF
(PsAF) remains a challenge for clinical practice. Due to the underlying
structural, electrical, and autonomic pathologic remodeling of PsAF, the
success rate could decrease over time. Although reports have indicated
that atrial and pulmonary vein (PV) muscle sleeve microstructural
remodeling is present in AF establishing a vulnerable substrate for AF
maintenance, there are more non-PV foci
atrial
substrates for the maintenance of
AF.3 Non-PV foci
commonly arise from the left atrial posterior wall (LAPW), left atrial
appendage, and the superior vena cava, and so
on.4 Based on PV
isolation, additional LAPW isolation has been reported as an effective
strategy for improving the ablation outcomes for
PsAF.5,
6 Furthermore, LAPW isolation has also
been performed for paroxysmal AF
(PAF).5,
7 One of the classic LAPW isolation
approaches involves a wide antral PV isolation, followed by roofline and
conventional posterior line (CPL). The CPL is usually connected to the
most inferior margin of the inferior
PVs6,
8 or the posterior-inferior part of two
inferior PVs.9,
10 Due to the anterior aspect of the
esophagus was directly opposed to the LAPW, the CPL could not avoid
touching the
esophagus.11 Therefore,
it is predictable that the adjunct ablation on LAPW, theoretically,
increases the risk of esophageal injury and even result in an
atrio-esophageal fistula (AEF). Previous studies investigated the
myocardium of LAPW and tissue layers between LAPW and esophagus by
multidetector computed tomography (CT), intracardiac echocardiography,
specimen and histological
analysis.12-14 However,
only a few studies have compared the distance from the endocardium of
LAPW to the esophagus between different levels of
LAPW.12,
13 In this study, a modified approach of
LAPW isolation was proposed by replacing CPL with a modified
posterior-inferior line (MPL), which was in a lower region of LAPW than
CPL. The anatomical difference between CPL and MPL were compared in
patients with AF using enhanced
multidetector CT analysis.