Abstract 12600: Microrna From Atrial Tissue Harvested During Transseptal Puncture as a Predictor for Non-pv Trigger in Patients Undergoing Af Ablation: Preliminary Results From a Pilot Study

Abstract

Introduction: Catheter ablation of atrial fibrillation (AF) is the most valid therapeutic option to achieve rhythm control. Pulmonary veins (PV) are the most known trigger of AF, although recently we have become more aware of the importance of non-PV triggers. Expression of microRNA (miRNA) has been shown to be regulated in many cardiovascular disease. We sought to study expression patterns of miRNA in patients (pts) with AF undergoing ablation to facilitate their application as both diagnostic and prognostic markers. Methods: As part of the standard procedure for AF ablation a double transseptal sample of myocardial tissue is obtained via a transseptal needle. The small piece of atrial septal tissue can be retrieved from the needle as a result of piercing the atrial septum. MiRNA was hybridized to microarrays to determine relative levels of miRNAs in the samples. For a subset of the miRNAs we validated expression through quantitative real time PCR. All pts underwent PV-antrum and non-PV trigger ablation guided by isoproterenol challenge test. Results: Atrial tissue of 11 pts undergoing AF ablation has been utilized for MiRNA assessment. Mean age was 61.27 ± 10.5 years and 8 (72.7%) pts were male. Six (54.5 %) pts had paroxysmal AF. During the ablation non-PV triggers were detected in 8 (72.7 %) pts. Recurrence of AF occurred in 3(27.3 %) pts. Expression of miR-21, miR-26a and miR-29a was higher in pts with non-PV triggers, while miR-30c had lower expression in pts who had recurrence of atrial tachyarrhythmias. Spearman’s nonparametric correlation coefficient was calculated and miR-21, miR-26a, miR-29a were positively correlated with non-PV triggers (r = 0.58, p=0.06 for all three miRNAs), while miR-30c level had inverse correlation (r = (-) 0.78 %, p=0.005) with recurrence (Figure). Conclusions: Expression of miR-21, miR-26a, miR-29a correlates with the presence of non-PV triggers. This information could be clinically relevant in planning patient specific procedures.