TBX20 and Arrhythmia: Thus, Tbx20 is not only important to heart development but also contributes to adult heart function, homeostasis, and physiological and pathophysiological adaptation (Stennard et al., 2005), which is further confirmed by severe dilated cardiomyopathy, arrhythmias, and heart failure in Tbx20 conditional knockout adult cardiomyocytes (Shen et al., 2011).