Increased serum oxidative stress in patients with severe mitral regurgitation: A new finding and potential mechanism for atrial enlargement

Objective: The aim of this study was to examine the serum oxidative stress in patients with severe mitral regurgitation. Design and methods: This study analyzed serum oxidative stress index in patients with severe mitral regurgitation [persistent atrial fibrillation (AF) or sinus rhythm], paroxysmal lone AF patients and healthy subjects. Results: The serum oxidative stress index was significantly higher in the mitral regurgitation AF group and sinus group than in the lone AF group and healthy subjects (p < 0.0001). Left atrial size was significantly larger in the mitral regurgitation AF group and sinus group than in the lone AF group and healthy subjects (p < 0.0001). The oxidative stress index significantly and positively correlated with left atrial size in the overall study population (r = 0.439, p = 0.0008). Conclusions: This study provides new evidence of increased oxidative stress in human severe mitral regurgitation, probably contributing to atrial enlargement.