Left atrial stiffness measured by echocardiography is a stronger predictor of atrial fibrillation recurrence after radiofrequency catheter ablation than left atrial volume

Introduction Left atrial volume (LAV) is an accepted predictor of atrial fibrillation (AF) recurrence after radiofrequency catheter ablation, stronger than AF duration. Objective The aim of this study was to assess the value of left atrial stiffness (LAS) index as a new parameter evaluated by echocardiography to the prediction of AF recurrence after radiofrequency catheter ablation. Methods We retrospectively studied consecutive patients with paroxysmal or persistent AF submitted to radiofrequency catheter ablation at our institution between 2017 and 2019. We used transthoracic echocardiography to measure the LAV indexed to body surface area and the LAS index, defined as the ratio between the mitral E/e' (obtained with pulsed Doppler at the tip of the mitral leaflets – E, and tissue Doppler imaging at the mitral annulus – e') and the left atrial strain during the reservoir phase (obtained by speckle tracking echocardiography) [LAS index = (E/e') / LA reservoir strain]. The left ventricular ejection fraction (LVEF) was also evaluated. Patients with poor quality echocardiographic images were excluded. We compared 2 groups of patients, according to the recurrence of AF after the blanking period. We analysed the clinical characteristics and echocardiographic findings. The effect of clinical and echocardiography parameters on AF recurrence was evaluated by univariate and multivariate Cox Regression analysis. Results We studied 33 patients, 27 with paroxysmal AF and 6 with persistent AF. Baseline patients' characteristics are presented in Table 1. During a mean follow-up time of 17.9±10.4 months, 7 patients (21%) had AF recurrence, and none died. Patients with AF recurrence had a higher LAS index. After adjusting for confounding variables, only LAS index and LAV were independently associated with AF recurrence (Table 2). Every one unit increase in LAS index was associated with an 11-fold increased risk of AF recurrence (HR 10.86, 95% CI 1.38–85.56; p=0.024), while every one unit increase in LAV index was only associated with a 6% increased risk of AF recurrence (HR 1.06, 95% CI 1.01–1.11, p=0.010). Conclusion LAS index evaluated by echocardiography was a much stronger predictor of AF recurrence after radiofrequency catheter ablation than left atrial volume. FUNDunding Acknowledgement Type of funding sources: None.