GWAS unexpectedly identified genetic variants in SCN10A that were strongly associated with AF, Brugada syndrome (Box 2), cardiac conduction velocity, heart rate, and heart rate response to exercise and after exercise (Bezzina et al., 2013; Roselli et al., 2018; Nielsen et al., 2018; Eppinga et al., 2016; Nolte et al., 2017; Ramirez et al., 2018; Verweij et al., 2018). This evidence concerns the gene SCN10A and atrial fibrillation.