1. Abstract
Background: The efficacy of ablation targeting low-voltage
areas (LVAs) is controversial, although LVA presence is well known to be
associated with AF recurrence after ablation. Atrial fibrillation (AF)
substrate may not localize within LVAs.
Methods and results: This observational study enrolled 405
consecutive patients who underwent an initial AF ablation procedure. The
left atrial voltage map was obtained after pulmonary vein isolation.
LVAs were defined as areas with voltage < 0.5 mV. To estimate
whole atrial electrophysiological degeneration, mean regional voltage at
each of 6 regions and left atrial total conduction velocity were
measured. LVAs existed in 143 of 405 (35.3%) patients. Patients with
LVAs demonstrated lower mean regional voltages throughout all 6 regions
than those without LVAs (1.3 [1.8, 0.8] vs. 0.6 [1.0, 0.2] for
anterior wall, p<0.001). On the other hand, left atrial
conduction velocity was lower in patients with LVAs than in those
without (0.89 [1.01, 0.74] vs. 0.93 [1.03, 0.87] m/s,
p<0.001). Multivariate analysis revealed that low left atrial
total conduction velocity and a higher number of regions with mean
voltage reduction were independently associated with AF recurrence,
although LVA presence was not.
Conclusion: Patients with localized left atrial LVAs were
characterized by whole left atrial electrophysiological degeneration as
assessed by mean regional voltage and conduction velocity.
In addition, whole left atrial
electrophysiological degeneration parameters were well associated with
AF recurrence.
Key words: atrial fibrillation; low-voltage areas; recurrence;
ablation; conduction velocity; regional voltage