The combination of peripheral vascular resistance, fluid volume and cardiac output influence the level of blood pressure.
Diuretics act to decrease the volume of fluid and thus lower the pressure.
A patient with mild to moderate hypertension may be treated with changes in diet, exercise and be placed on a diuretic. With more severe cases of hypertension their may be use of ACE inhibitors, Calcium Channel Blockers, Alpha adrenergic blockers or any of these combined with a diuretic. Congestive heart failure is associated with pitting edema in the extremities as seen below. As the heart tries to compensate for reduced efficiency, enlargement of the heart occurs along with an increase in heart rate and dilatation. As the CHF progresses the contractility of the heart decreases and fluids accumulate in the peripheral extremities.