The role of novel inotropic agents in the treatment of heart failure.

While the acute hemodynamic efficacy and safety of the novel inotropic agents are well recognized, their long-term effects on symptoms, quality of life, and survival, in patients with chronic congestive heart failure, are controversial. Such controversy may result from a poor understanding of the disease process and its progression, unrealistic expectations on the potential benefits of enhancing myocardial contractility at an advanced stage of the disease, and the lack of knowledge of the precise mechanisms of action of the novel inotropic agents. To put into perspective the role of the novel inotropic agents in the treatment of chronic congestive heart failure, the effects of dobutamine (a synthetic catecholamine which is the most potent inotropic agent currently available) were reviewed. Changes in cardiac performance, myocardial contractility and metabolism, and exercise capacity were studied in patients with chronic congestive heart failure of variable severity. The acute hemodynamic effects and the mechanism of action of the novel inotropic agents were then reviewed and compared to those of dobutamine. Which patients with chronic congestive heart failure who are the most likely to benefit from therapy with the novel inotropic agents, and the therapeutic limitations of these agents are discussed. Lastly, the difficulties of selecting the right endpoints to demonstrate the long-term efficacy of the novel inotropic agents are considered.