Starting with the morphology of the myoendocrine cell and the biochemistry and physiology of cardiac hor mones, the book describes pathophysiological findings and discuss their clinical relevance in congestive heart failure, arterial hypertension, renal insufficiency, and cirrhosis of the liver. Furthermore, evidence is presented for the role of the heart as a target organ for various endocrine factors such as thyroid hormones, catecholamines, renin-angiotensin, growth hormones and endogenous opioids.