Electrolyte and water balance in cardiac insufficiency. Recent clinical and experimental data.

The reasons for the disturbances of electrolyte and water balance in cardiac failure are not yet clarified. The decrease of cardiac output in cardiac insufficiency causes humoral regulatory mechanisms such as increased activity of the renin angiotensin-aldosterone system and increased secretion of antidiuretic hormone. These mechanisms in turn lead to an enhancement of renal sodium and water reabsorption. The humoral disturbances can be interpreted as ineffective regulatory mechanisms for hemodynamic changes in cardiac insufficiency; in fact, the humoral disturbances increase cardiac failure. In addition, an increased sodium content of the arteries may contribute to the hemodynamic changes in cardiac insufficiency.