Circulating miR-20b-5p and miR-330-3p Are Novel Biomarkers for Progression of Atrial Fibrillation: Intracardiac/Extracardiac Plasma Sample Analysis by Small RNA Sequencing

Abstract Background: Circulating miRNA expression in the peripheral blood samples might not reflect a cardiac phenomenon since most miRNAs are expressed in numerous organs. This study aimed to identify the cardiac-specific circulating miRNAs as biomarkers for atrial fibrillation (AF).Methods: Plasma samples were obtained from a luminal coronary sinus catheter (CS, cardiac-specific samples) and femoral venous sheath (FV, peripheral samples) in AF patients and controls undergoing catheter ablation (CA). Small RNA sequencing was performed to identify differently expressed miRNAs between AF and CTL in each sample of the CS and FV; miRNAs exhibiting similar expression profiles in the CS and FV samples were selected as candidates for cardiac-specific biomarkers, and were related to the outcome of CA of AF.Results: Among the top 30 most differently expressed miRNAs between AF and CTL, circulating hsa-miR-20b-5p/miR-330-3p/miR-204-5p had a similar pattern in the CS and FV samples. Another set of peripheral samples was obtained from AF patients undergoing CA (n=141). The miR-20b-5p/miR-330-3p expressions negatively correlated with the echocardiographic left-atrial dimension and was significantly decreased in patients with AF recurrence as compared to those without AF recurrence.Conclusion: Circulating miR-20b-5p/miR-330-3p can be cardiac-specific biomarkers for atrial remodeling and arrhythmia recurrence after CA in AF patients.