MMP-1 and MMP-3 polymorphism and arrhythmia recurrence after electrical cardioversion in patients with persistent atrial fibrillation

Objectives: Cardiac extracellular matrix structure is largely under the control of the matrix metalloproteinases (MMPs) whose activity maintains a balance between connective tissue synthesis and degradation. MMP gene polymorphisms, by modifying the level of gene expression, may affect atrial structural remodelling and atrial fibrillation recurrence rate. The aim of this study was to evaluate the association between MMP-1 and MMP-3 polymorphisms and arrhythmia recurrence. Methods: We studied 74 persistent atrial fibrillation patients who underwent electrical cardioversion to restore sinus rhythm. In both patient and reference control groups, identification of MMP-1 and MMP-3 gene polymorphisms was performed by means of polymerase chain reaction according to standard techniques. Results: Distribution of MMP-1 and MMP-3 genotypes and alleles were similar in atrial fibrillation patients and controls. During a 3-week follow-up period, 37 patients showed atrial fibrillation recurrences. Risk for atrial fibrillation recurrence significantly differed among groups (P = 0.0139) according to 5A and 1G allele presence. In particular, atrial fibrillation recurred in 62% of the patients carrying both 5A and 1G alleles (reference group) compared with no recurrence in patients carrying neither of them. Conclusions: We observed a significant relationship between MMP-1 and MMP-3 polymorphism and atrial fibrillation recurrences in patients with persistent atrial fibrillation. These findings suggest that genetic factors contribute to determine arrhythmic recurrence rate in persistent atrial fibrillation