Clinical factors associated with extensive LVAs
Although several methods for preoperative prediction of the presence of
LVAs have been reported 21-23, the present study
showed that widespread LVAs worsen the clinical prognosis. We identified
the following as independent predictors of extensive LVAs: female, low
BMI, and large LAD (Table 4). These factors have been reported to be
related to LVAs in the past, and we discuss them here with reference to
these reports.
These previous reports identified mechanisms underlying the sex
differences in atrial fibrosis. 24 On histological
analysis of atrial tissue, females showed stronger expression of CX40
than males, which indicates remodeling-induced change in connexins.25 In addition, fibrosis-related genes were
upregulated in post-menopausal woman with AF. 26Clinically, females reportedly experience AF recurrence more frequently
than males during long-term follow-up after AF ablation, likely due to
non-PV arrhythmogenicity. 27
The reason why low BMI and large LAD are associated with extensive LVAs
may be that they both reflect wall stress on the LA. As reported
previously, LVA is a result of the progression of remodeling. LA
remodeling in AF patients is suggested to be associated
with
continuous internally generated stretch and wall stress.9,28-30 Anatomical contact with external structures
surrounding the LA provokes the perpetuation of AF by arrhythmogenic
substrates in patients with persistent AF. 31,32 In
patients with low BMI, the distance between the LA and external
structures such as the vertebral bodies may be close enough to trigger
the development of LVA.