DISTURBANCE OF PERIPHERAL MICROVASCULAR FLUID PERMEABILITY BY THE ONSET OF ATRIOVENTRICULAR ASYNCHRONY IN PATIENTS WITH PROGRAMMABLE PACEMAKERS

Background-In vitro and in vivo evidence suggests that atrial natriure tic peptide can enhance fluid flux from intravascular to extravascular compartments. The relevance of this to human pathophysiology remains unclear. Objectives-To determine whether a central haemodynamic change associated with increased plasma concentrations of atrial natriuretic peptide produces detectable change in the capillary filtration coeffi cient in a peripheral microvascular bed. Patients-12 patients with pro grammable dual chamber permanent pacemakers. Methods-Calf capillary fi ltration coefficient (using a modified plethysmographic technique) and plasma atrial natriuretic peptide concentrations were measured during atrioventricular synchronous and ventricular pacing. Results-Atrioven tricular asynchrony was associated with higher mean (SD) concentration s of atrial natriuretic peptide (231.9 (123.1) v 53.5 (38.8) pg/ml) an d an increased mean (SD) calf capillary filtration coefficient (4.2 (1 .1) v 3.6 (1.1) ml/min.mm Hg.100 ml x 10(-3)), but there was no correl ation between the magnitude of the change in these variables in indivi dual patients. Conclusions-The peripheral capillary filtration coeffic ient may change in response to altered central haemodynamics. Atrial n atriuretic peptide remains one potential candidate mechanism, but othe r factors are also likely to be involved.