The peripheral microcirculation in atrial fibrillation: preservation of capillary pressure and filtration coefficient.
OBJECTIVE
The aim was to assess whether atrial fibrillation results in disturbances of capillary pressure and capillary filtration coefficient in man.


METHODS
Finger nailfold capillary pressure and calf capillary filtration coefficient were measured in subjects in atrial fibrillation and in matched healthy controls in sinus rhythm. Capillary pressure was measured by direct cannulation using an electronic resistance feedback servonulling technique, and capillary filtration coefficient by mercury-in-Silastic strain gauge plethysmography using a technique believed not to invoke the venoarteriolar response.


RESULTS
Mean capillary pressure did not differ significantly between subjects in atrial fibrillation and those in sinus rhythm [18.4(SD 5.1) mm Hg in atrial fibrillation v 18.0(2.9) mm Hg in sinus rhythm]. In a subgroup of patients restored to sinus rhythm (n = 7) by dc cardioversion there was no significant alteration in capillary pressure [15.3(4.2) mm Hg v 16.6(2.8) mm Hg]. Capillary filtration coefficient was also similar in subjects in atrial fibrillation to that in healthy controls in sinus rhythm [2.81(0.65) kfu in atrial fibrillation v 2.87(0.69) kfu in sinus rhythm].


CONCLUSIONS
These data would suggest that under resting conditions autoregulatory mechanisms are able to preserve microvascular homeostasis despite the central changes associated with atrial fibrillation.
Mahy
I R
IR
Department of Vascular Medicine, University of Exeter, Postgraduate Medical School, United Kingdom.
Shore
A C
AC
Smith
L D
LD
Tooke
J E
JE
D001281:Atrial Fibrillation / Q000503:physiopathology*; D001794:Blood Pressure / Q000502:physiology; D002196:Capillaries; D002199:Capillary Permeability / Q000502:physiology; D005260:Female; D005385:Fingers / Q000098:blood supply*; D006706:Homeostasis; D006801:Humans; D007866:Leg / Q000098:blood supply*; D008297:Male; D008833:Microcirculation / Q000503:physiopathology; D008875:Middle Aged; D010991:Plethysmography