Introduction
Recurrent atrial fibrillation (AF) after catheter ablation (CA) is a
common clinical problem. Main cause of AF recurrence is pulmonary vein
(PV) reconnection. Nevertheless, some patients experience a recurrence
even after complete PV isolation. These outcomes are likely explained by
the development of an atrial arrhythmogenic substrate and a non-PV
trigger. The previous study has failed to demonstrate the efficacy of CA
with substrate modification for AF.1 Recent reports
suggested that ablation for low voltage area (LVA) in addition to PV
isolation improved procedural outcomes in patients with
AF.2 However, these strategies for LVA have
insufficient success rate.
It is known that atrial remodeling due to AF causes an increase in
fibrosis, which is associated with a reduction in conduction velocity,
and a consequent increase in susceptibility to AF.3Regions of slowed conduction have classically been considered markers of
disease tissue that enable arrhythmia perpetuation, and that may sustain
atrial arrhythmia.4 Previous studies reported that
fibrosis of the left atrium (LA), resulting in conduction abnormality,
appears to be associated with higher recurrence
rates.5 Recently, Mouws et al reported that conduction
abnormalities were associated with AF.6 However,
little has been reported on the abnormal conduction zone (ACZ) of the
LA.
The Advisor HD grid mapping catheter (HD Grid, Abbott) was released in
2019. Using the HD Grid can create
a detailed voltage map and local activation map. Furthermore, previous
studies suggested that AF itself and other factors, such as compression
from the external structures, can promote atrial remodeling. Hori et al
investigated the relationship between the contact area (CoA) of the LA
with external anatomical structures in 22 AF patients. They indicated
that LVA had a strong association with CoA.7 Although
the ACZ may be regions of interest in sustained AF, detailed
electrophysiological studies describing the nature of the ACZ are
lacking. We focused on the ACZ, and investigated the characteristics of
the ACZ and whether the ACZ was
related to the LVA or the LA anatomical CoAs with other organs in
patients with AF.