In a pilot study of participants with mitral stenosis and atrial fibrillation, participants with higher heart rates (>100 bpm) were found to have significantly higher levels of coagulation factors (prothrombin fragment 1+2, thrombin antithrombin III and PAI) when compared with participants with lower heart rates (≤100 bpm).14 The gene discussed is SERPINE1; the disease is atrial fibrillation.