Afterload reduction in the treatment of cardiac failure.

The vasodilators produce disparate modifications of cardiac function depending on the differing alterations of preload versus impedance: nitrates principally cause venodilation; nitroprusside, phentolamine and prazosin produce balanced arterial and venous dilation; while hydralazine predominantly effects arterial dilation. Combined nitroprusside and dopamine or dobutamine synergistically enhance low cardiac output and decrease raised left ventricular end-diastolic pressure. Ambulatory oral vasodilator therapy is provided by long-acting nitrates, hydralazine and prazosin alone, combined nitrate-hydralazine and combined prazosin-hydralazine. It is truly remarkable how quickly systemic vasodilators have become established as an important new medical advance in acute and chronic congestive heart failure treatment. In the future, as more experience is gained with the vasodilators and as newer such agents become available, the systemic vasodilators likely will be utilized as often as digitalis in the standard treatment of congestive heart failure.