Introduction: Atrial fibrillation (AF) is the most common arrhythmia in patients with mitral stenosis (MS) and it may increase complications and decreases success rates of percutaneous balloon mitral valvotomy (PBMV). This study aimed to investigate the short and long term results of PBMV in patients with AF compared to sinus rhythm (SR). Methods: In this cross sectional study, 1000 patients with MS who had undergone PBMV between 1999 and 2013 were enrolled including 585 and 415 patients with AF and SR respectively. Patients were followed for a mean of 7.27 ± 3.16 years. Clinical, echocardiographic and hemodynamic data were collected. Procedure success, in-hospital and long-term outcome were evaluated. Results: Patients with AF were older and had greater symptoms, mitral regurgitation, mitral echocardiographic score, and mitral pressure gradient before PBMV. PBMV success rate were significantly lower in AF group (P < 0.001). In-hospital complications, including severe mitral regurgitation, emergency mitral valve surgery, peripheral embolism and long-term complications, including mortality, re-valvotomy, mitral replacement surgery and peripheral embolism/stroke were significantly higher in patients with AF. Conclusion: AF leads to worse in-hospital and long-term outcome and lower PBMV success rate. Repeated assessment and early decision to PBMV in patients with MS to reduce AF and AF related complication seems necessary.

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