MPO aggregations co-localized with fibrofatty strands that penetrated the myocardium in 70% ofpatients with persistent AF, in 33% with paroxysmal AF, in 27% with future onset AF, and in 7% of the non-AF patients (p = 0.01) (Additional file 1: Fig. S5). This evidence concerns the gene MPO and atrial fibrillation.