Diuretics in heart failure: some knowns and unknowns.

There are many hemodynamic faces of heart failure, ranging from the subclinical to the terminal syndrome. The diuretics possess, with minor qualification, the pharmacotherapeutic attributes of the ideal first-line drug of choice. In heart failure, the loop diuretics have achieved eminence due to their improvement of the deranged hemodynamic profile without significant adverse pharmacologic effects. The new loop diuretics, including torasemide, have been shown to reduce the raised pulmonary vascular pressures without significant depression of the cardiac output in patients with chronic heart failure. This hemodynamic improvement has been paralleled by a significant improvement in clinical symptoms in the majority of patients. The undoubted and widely accepted efficacy of the loop diuretics in all the heart failure syndromes have presented a formidable ethical obstacle to their formal testing in terms of improvement in exercise capacity and reduction of mortality risk. There is still a paucity of information on their singular impact on the excited neuroendocrine reflexes in heart failure and their influence on the widespread metabolic disturbances occasioned by pumping failure of the heart. From the clinical standpoint, however, these deficiencies in information do nothing to reduce the importance of the loop diuretics in the treatment of acute and chronic heart failure.