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 +/- A 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 30A degrees view. During follow-up, AF recurred in 35 patients (22.6 %). Mean LA EF1 was 37.9 +/- A .8 % in the AF recurrence group and 48.0 +/- A 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 +/- A 3.4 in the AF recurrence group and 5.2 +/- A 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.In conclusion, the LA EFs of the second and third beats after RVP, as a surrogate marker of LA functional reservoir and LAA EF, are strong independent predictors of AF recurrence after CA in patients with paroxysmal AF. This finding supports the clinical application of RVP in LA angiography during CA. In addition, among clinical risk factors, OSA is an independent predictor of AF recurrence. However, these findings require validation in a large population