The use of diuretics in heart disease

Abstract

Diuretics are employed in heart disease primarily to ameliorate the clinical consequences of heart failure. This is the objective of the clinical cardiologist, from whose viewpoint I make this presentation. The pharmacologist uses diuretics to increase the elimination of sodium and water. The physiologist has demonstrated an abnormal retention of sodium and water in heart failure, and recognizes the effectiveness of diuretics in overcoming this abnormality. He would prefer a more direct attack on the failing heart itself or on the immediate unphysiological consequences of the failing heart, such as the deficient arterial blood supply or the rising pressures behind the failing chamber, or on the receptors or mechanisms which lead to sodium and water retention, but these are all uncertain. The clinician has noted in the patient with heart failure the inability to tolerate salt in contrast with the capacity for handling relatively large quantities of water, and has been impressed by the therapeutic effectiveness of restricting sodium intake and the ineffectiveness of restricting water intake when sodium intake is unrestricted. These clinical observations conformed with the physiologist’s teaching that water retention and water elimination were generally secondary to similar movements of sodium. But in recent years the progressively greater intrusion of the experimental physiologist, the pharmacologist and the biochemist into the clinic has complicated the simple therapeutic routine of the clinical cardiologist. He has learned that water may be retained in disproportion to salt, that water as well as salt may have to be restricted, that he must quantitate sodium and water restriction to the individual patient, that he must choose from a variety of diuretic agents with different pharmacological actions, and that heart failure itself or the diuretic agents may be responsible for serious disturbances in electrolyte and water metabolism which may interfere with any further effectiveness of the diuretic agents.