Left atrial functional reservoir: predictive value for outcome of catheter ablation in paroxysmal atrial fibrillation

Left arial (LA) function, defined according to conduit, reservoir and booster functions, is closely linked to left ventricular (LV) mechanics, particularly during diastole. Right ventricular pacing (RVP) is thought to impair LA diastolic restoring forces through alteration of ventricular activation. The aim of this study was to determine whether the LA functional reservoir estimated as the change in mean LA ejection fraction (EF) immediately after RVP, and for the second and for the third beats after RVP, predicts clinical outcome in patients with paroxysmal atrial fibrillation (AF) who have undergone catheter ablation (CA). Data from 155 patients with paroxysmal AF (56.0 ± 10.6 years, M:F = 114:41) were analyzed. All patients underwent LA angiography during RVP. LA EFs were measured at the immediate first (LA EF₁), second (LA EF₂) and third beats (LA EF₃) after RVP, using a right anterior oblique 30° view. During follow-up, AF recurred in 35 patients (22.6 %). Mean LA EF₁ was 37.9 ± .8 % in the AF recurrence group and 48.0 ± 8.6 % in the non-recurrence group (P < 0.001). Mean LA EF₂ and LA EF₃ were also lower in the AF recurrence group than in the non-recurrence group (P < 0.001, respectively). Mean percent changes from LA EF₂ to LA EF₃ were −0.4 ± 3.4 in the AF recurrence group and 5.2 ± 4.9 in the non-recurrence group (P = 0.041). The change in mean EF from LA EF₁ to LA EF₃ in the non-recurrence group was significantly greater than in the recurrence group (P = 0.001). Cox regression analysis showed that predictors of AF recurrence were LA EF₂, LA EF₃ and accompanied obstructive sleep apnea (OSA) (P < 0.001, respectively). Decreased functional LA reservoir (LA EF after RVP) and OSA are significantly related to recurrence of AF following CA in patients with paroxysmal AF.