• AF predictors
• atrial fibrillation
• TDI
• transcatheter ablation

BACKGROUND: atrial fibrillation (AF) results in electrical and structural remodeling of the atria, and the extent of remodeling has already been found to be associated with higher AF recurrence rate after catheter ablation (CA). Recently, a novel echocardiographic parameter derived from tissue Doppler imaging (TDI), called PA-TDI, has been introduced to assess the total atrial activation time, as a non-invasive surrogate of fibrosis and remodeling.
The aim of the study is to investigate the role of PA-TDI interval as predictor of AF ablation efficacy.
METHODS: we retrospectively included patients with paroxysmal symptomatic drug-refractory AF referred to our Institution for catheter ablation procedure with radiofrequency, who presented sinus rhythm at admission. A complete transthoracic echocardiogram was performed before the ablation procedure and the PA-TDI interval was defined as the time-interval from the initiation of the P-wave from the ECG signal provided by the echo machine to the peak A’-wave on the TDI analysis.
RESULTS: from January 2015 to April 2018, 128 patients (mean age 61.86 ± 9.08 years, 68% male, BSA 1.97 ± 0.21 mq, BMI 26.98 ± 3.86 kg/mq, EF 59 ± 6.06%) with symptomatic drug refractory AF who received radiofrequency catheter ablation 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 LA size (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 (162 ± 33 msec vs. 133 ± 26 msec, p< 0.0001). At multivariate analysis, only the LA area (HR:1.13, 95%CI: 1.01–1.27; p=0.048) and PA-TDI interval (HR:1.01, 95%CI: 1.03–1.06; P=0.022) were independent predictors of AF recurrence. A cut-off of PA-TDI > 150 ms identified patients with recurrence after ablation with a sensibility of 82% and specificity of 83% (AUC 0.879).
CONCLUSION: 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.