Circadian rhythms participate in normal cardiac development and disease in vivo: altered circadian biology is associated with cardiac arrhythmias, myocardial infarction, hypertension, and diabetes (16, 17), and the loss of Bmal1 in myocytes from birth causes dilated cardiomyopathy and metabolic dysfunction (18). This evidence concerns the gene BMAL1 and dilated cardiomyopathy.