Herz
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Ventricular dysfunction due to an abnormality of the heart which is associated with typical hemodynamic, renal and hormonal reactions, characterizes the clinical syndrome heart failure. The traditional definition of heart failure as the inability to pump an amount of blood sufficient to cover the metabolic needs of the body in the presence of adequate venous return, emphasizes mainly the reduction in cardiac output but not the increase in intracardiac pressures. Pressure or volume overload, decreased contractility, loss of muscle mass or restricted filling represent the most important pathological processes leading to heart failure. ⋯ With increasing derangement of cardiac function, there is recruitment of the compensatory mechanisms: hypertrophy of the cardiac muscle, Frank-Starling mechanism, activation of the sympathetic nervous system, the renin-angiotensin-aldosterone system and the arginine-vasopressin system. The goal is maintenance of adequate blood pressure and cardiac output whereby blood flow is redistributed in favor of the heart and brain and away from the skin, musculature and visceral organs. Activation of the neurohumoral system can lead to excessive vasoconstriction as well as sodium and water retention resulting in an undesired elevation of preload and afterload which, in turn, leads to further worsening of the heart failure.(ABSTRACT TRUNCATED AT 400 WORDS)