Impact of pharmacotherapy on lymphocyte volumes and activity of the Na+/H+ exchanger in patients with congestive heart failure.

Previous studies in patients with congestive heart failure (CHF) have revealed abnormalities of cellular volume that might have an impact on the dysregulation of peripheral vascular resistance. Human mononuclear leukocytes (HML) represent a model for the study of cellular volume regulation, We investigated the impact of enalapril and carvedilol on HML volume and on the activity of the Na + /H + exchanger in 26 patients with CHF and 20 volunteers. Over a period of 4 weeks, 18 patients received enalapril in addition to the previous therapy while 8 patients additionally received carvedilol. HML diameters and the activity of the Na + /H + exchanger were measured by a Coulter Counter. Both patient groups showed abnormally increased initial volumes of HML compared to the volunteer group at baseline. Four weeks of therapy with enalapril in addition to therapy with diuretics and digoxin did not result in a statistically significant reduction of lymphocyte volume, whereas add-on therapy with carvedilol to therapy with ACE inhibitors, diuretics and digoxin reduced the volume significantly. Alterations could not be found in the activity of the Na + /H + exchanger in either patient group compared to volunteers. Supplementary drug therapy with carvedilol in patients with CHF leads to a reduction of the increased lymphocytic volume, possibly reflecting the beneficial effect of β-blockade.