The therapeutic principle of pharmacological vasodilation in congestive heart failure is based upon established physiological and pathophysiological mechanisms and has been proved to be effective and useful. In acute heart failure this method of treatment has assumed importance as the first measure to be taken. In chronic heart failure a sizeable increase in cardiac output can be achieved with a number of vasodilating drugs. This effect can be maintained over several weeks or months. The adjustments of the heart and the circulation to the arteriolar and/or venous unloading effect of...