A Long Atrial Electromechanical Interval is Associated with Arrhythmic Recurrence after Catheter Ablation: How to Find What Has Been Lost

Background: Atrial fibrillation (AF) results in electrical and structural remodeling of the atria, which extent is known to be associated with a higher AF recurrence rate after catheter ablation (CA). Recently, a novel echocardiographic parameter derived from tissue Doppler imaging (TDI) [PA-TDI] has been introduced to assess the total atrial activation time, as a noninvasive surrogate of fibrosis and remodeling. The aim of the study is to investigate the role of PA-TDI interval as a predictor of AF ablation efficacy. Methods: We retrospectively included patients with paroxysmal symptomatic drug-refractory AF referred to our institution for CA procedure, who presented sinus rhythm at admission. A complete transthoracic echocardiogram was performed before the ablation procedure, including the assessment of PA-TDI interval. Results: From January 2015 to April 2018, 128 patients (mean age: 61.86 ± 9.08 years, 68% male, body surface area: 1.97 ± 0.21 mq, body mass index: 26.98 ± 3.86 kg/mq, and ejection fraction: 59% ±6.06%) with symptomatic drug-refractory AF who received radiofrequency CA were enrolled. During the follow-up of 15.80 ± 6.7 months, 30 patients (23%) developed AF recurrence out of the blanking period. Compared with those without recurrence (group 1), patients with recurrence (group 2) had a larger left atrium (LA) size (Group 1 vs. Group 2: mean LA area: 22.2 ± 4.6 cmq vs. 25 ± 6.6 cmq, P = 0.015; mean indexed LA volume: 35 ± 10 mL/mq vs. 40 ± 12 mL/mq, P = 0.04) and longer PA-TDI interval (Group 1 vs. Group 2: 162 ± 33 ms vs. 133 ± 26 ms, P < 0.0001). A cutoff of PA-TDI > 150 ms identified patients with recurrence after ablation with a sensibility of 82% and specificity of 83% (area under the curve 0.879). Conclusions: The total activation time assessed by PA-TDI is an independent predictor of AF recurrence and can be used to predict the efficacy of transcatheter ablation.