Left atrial size and total atrial emptying fraction in atrial fibrillation progression.

Background: Left atrial (LA) size and low-voltage areas (LVA) mirror atrial fibrillation (AF) progression. Whether these factors are important for the impairment of total atrial emptying fraction is understudied.

Objective: The aim of the present analysis was to investigate the association between LA volume and total atrial emptying fraction with AF progression phenotypes: persistent AF and LVA.

Methods: Patients undergoing first AF ablation were included in the analysis. LVA were determined using high-density maps and defined as <0.5 mV. All patients underwent cardiovascular magnetic resonance imaging before the intervention. Cardiovascular magnetic resonance data (LA volume, LA emptying fraction [LA-EF], and right atrial emptying fraction [RA-EF]) were measured in all patients.

Results: The study population included 211 patients (65 ± 11 years; 124 (59%) men; 122 (58%) persistent AF; 54 (26%) LVA). There were 4 disease progression groups: paroxysmal AF without LVA, paroxysmal AF with LVA, persistent AF without LVA, and persistent AF with LVA. While LA volume increased according to the AF progression phenotype (98 ± 27, 145 ± 34, 134 ± 41, 141 ± 39 mL, respectively; P < .001), total LA-EF (51% ± 17%, 32% ± 17%, 33% ± 17%, 22% ± 11%; P < .001) and RA-EF (47% ± 13%, 36% ± 17%, 30% ± 16%, 23% ± 12%; P < .001) decreased. In multivariable analysis, age (odds ratio [OR] 1.084; 95% confidence interval [CI] 1.028-1.142; P = .003), persistent AF (OR 3.478; 95% CI 1.117-10.830; P = .031), and total LA-EF (OR 0.933; 95% CI 0.899-0.968; P < .001) showed a significant association for LVA. Using receiver operating characteristic curve analysis, LA-EF (area under the curve 0.778; 95% CI 0.711-0.846; P < .001) and RA-EF (area under the curve 0.726; 95% CI 0.650-0.802; P < .001) were significantly associated with the absence of LVA.

Conclusion: LVA and persistent AF are associated with worse total atrial emptying fraction.