Definition From Miller “Cardiac hormones are polypeptides secreted by cardiac tissues into the circulation in the normal heart. Natriuretic peptides, aldosterone, and adrenomedullin are hormones secreted by cardiomyocytes. Angiotensin II, the effector hormone in the renin-angiotensin system, is also produced by cardiomyocytes. The renin-angiotensin system is one of the most important regulators of cardiovascular physiology. […]