NPPB and atrial fibrillation: To explore the feasibility and clinical value of early recurrence prediction model for persistent atrial fibrillation after catheter ablation based on brain natriuretic peptide (BNP), angiotensin II(Ang II), homocysteine, monocyte-to-high density lipoprotein cholesterol (MHR) and neutrophil-to-lymphocyte ratio (NLR).