Pathogenesis and Management of Acute Heart Failure and Cardiogenic Shock: Role of Inotropic Therapy

¹ The Cardiology Division, The University of Texas Medical School at Houston, Houston.

Mortality from myocardial infarction has improved in the last decade with the introduction of new therapeutic strategies, in particular the widespread use of thrombolytic agents and the increasing use of β-adrenergic blockade. However, the most common cause of in-hospital mortality still remains pump failure and cardiac rupture. Patients with acute heart failure or cardiogenic shock have a poor prognosis that has not changed in the last decade. Initial treatment in these patients must be to limit the extent of myocardial infarction by reperfusion of the infarct-related coronary artery by thrombolysis and if unsuccessful by coronary angioplasty. Once loss of contractile myocardium occurs, a complex chain of events is initiated, many of which are often detrimental and result in a vicious cycle producing an inexorable decline in cardiac function. Treatment of these patients requires careful clinical and hemodynamic evaluation to exclude any underlying, potentially remediable cause of heart failure or cardiogenic shock. Thereafter, therapy should be guided by the patient's prevailing hemodynamic status with the judicious use of inotropic agents and/or vasodilators and diuretics if required. The therapeutic regimen may have to be altered to suit a change in the patient's hemodynamic status. It is critical to understand the effects of pharmacologic agents and to have a clear idea of the goals of such therapies. One also has to be cognizant of how each of the various hemodynamic variables interacts with one another to produce an optimal hemodynamic effect. The appropriate use of inotropic agents provides the clinician with an important pharmacologic tool in the treatment of the patient with acute heart failure or cardiogenic shock following myocardial failure.