5.1 Association between localized LVA presence and whole left
atrial electrophysiological degeneration.
Patients with localized LVAs demonstrated whole left atrial
degeneration, represented by an extensive mean regional voltage
reduction and a low left atrial total conduction velocity. Several
upstream factors causing atrial fibrosis have been reported, including
atrial stretch, aging, AF burden, hypertension, heart failure, alcohol,
obesity, and obstructive sleep apnea.13-17 These
upstream factors would promote atrial fibrosis not only at localized
areas, but also across the entire atrial myocardium. Therefore, when the
voltages at some portions of the left atrium were below 0.50mV - which
is a commonly used cut-off value of LVA - voltages at other areas likely
decreased in parallel, even if not below 0.50 mV.
Myocardial degeneration of the entire atrium in AF patients has also
been reported. Teh et al showed that AF patients had lower mean voltage,
slower conduction, and more prevalent complex signals at a majority of
left atrial regions than
controls.13