TTN and atrial fibrillation: Further, genes within our gene network that are regulated by the Chr2 eQTL containing Ttn are also dysregulated in atrial fibrillation (Rbm20, Atp2a2, Fndc5, and Mybphl) (Deshmukh et al. 2015) and dysregulation of transcription factors and ion/calcium handling genes could drive the switch from working myocardium to the pacemaker phenotype observed in the pulmonary myocardium in atrial fibrillation.