BACKGROUNDS Paroxysmal atrial fibrillation (AF) frequently, but not always, progresses to persistent/permanent AF. The aim of this study was to evaluate the echocardiographic predictors of AF progression in patients with paroxysmal AF.

METHODS A multicenter, prospective, observational study was conducted that included 313 patients with paroxysmal AF who underwent two-dimensional speckle-tracking echocardiography. The diameter, volume, and mechanical function of the left atrium, including global strain (ε) and ε rate, were measured.

RESULTS Progression to persistent or permanent AF occurred in 52 patients (16.6%) during a median follow-up period of 26 months. Echocardiographic measure of left atrial (LA) diameter, volume, and function (E velocity, E/A and E/e' ratio, LA expansion index, active emptying fraction, global longitudinal ε and ε rate) were associated with AF progression. LA ε ≤ 30.9% was the strongest predictor of AF progression, which was associated with a more than fourfold hazard increase for AF progression (hazard ratio, 4.224; P = .001). LA diameter > 39 mm and maximal LA volume index > 34.2 mL/m(2) were associated with about a twofold hazard increase for AF progression (hazard ratios, 1.994 and 2.649; P = .016 and P = .001, respectively). When adjusted for a model combining maximal LA volume index, E velocity, LA expansion index, and active emptying fraction, LA ε ≤ 30.9% maintained a more than threefold hazard increase for AF progression (adjusted hazard ratio, 3.970; P = .003).

CONCLUSIONS Echocardiographic measures of LA diameter, volume, and mechanical function, including LA ε, were associated with AF progression. LA ε was the strongest independent predictor of AF progression and is expected to serve as a valuable predictor of AF progression.