[Definition and classification of heart failure].

The definition of the syndrome of heart failure is dependent upon clinical, pathophysiological and biochemical criteria. The interrelationship of the contributing factors in a given hemodynamic situation must be clarified by simple examination. "Heart failure" implies a condition with insufficient peripheral perfusion, despite a normal blood volume, a sufficient or increased filling pressure, and intact intrinsic and extrinsic compensatory mechanisms. The cardiac output varies with basic illness. The worsening vicious cycle between cardiac dysfunction and neuroendocrinal dysregulation in chronic heart failure has to be taken into consideration, especially while planning therapeutic strategy. The classification of the severity of the disease is based upon simple, clear history taking and clinical examination. The conclusions have to be supported by radiological and echocardiografic observations. It is difficult to categorize patients during early stages of the disease. Prognosis is based on preexisting hemodynamic, biochemical, neuroendocrinal, and clinical parameters, as well as therapeutic strategy. At the same time, prognosis is dependent on the efficacy of the therapeutic regimen in any given situation.