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The peripheral microcirculation in atrial fibrillation: preservation of capillary pressure and filtration coefficient
I R Mahy1, A C Shore, L D Smith
1Department of Vascular Medicine, University of Exeter, Postgraduate Medical School, United Kingdom.
Insights
Atrial fibrillation (AF) does not appear to disrupt capillary pressure or filtration in humans at rest. Autoregulatory mechanisms maintain microvascular homeostasis despite AF-related central changes.
Area of Science:
- Cardiovascular Physiology
- Microcirculation Research
- Human Physiology
Background:
- Atrial fibrillation (AF) is a common arrhythmia affecting cardiac function.
- Potential impacts of AF on the microcirculation, specifically capillary pressure and filtration, remain unclear.
- Understanding these microvascular dynamics is crucial for managing AF-related complications.
Purpose of the Study:
- To investigate whether atrial fibrillation (AF) causes disturbances in human capillary pressure.
- To determine if AF affects the capillary filtration coefficient (CFC) in humans.
- To assess the role of autoregulatory mechanisms in maintaining microvascular homeostasis during AF.
Main Methods:
- Measured finger nailfold capillary pressure using direct cannulation and electronic feedback.
- Assessed calf capillary filtration coefficient (CFC) via strain gauge plethysmography.
- Compared measurements between individuals with AF and matched healthy controls in sinus rhythm.
Main Results:
- No significant differences in mean capillary pressure were observed between AF and sinus rhythm groups.
- Capillary pressure remained stable even after successful DC cardioversion in a subgroup of patients.
- Capillary filtration coefficient (CFC) values were similar in individuals with AF compared to healthy controls.
Conclusions:
- Resting microvascular homeostasis is preserved in individuals with atrial fibrillation.
- Autoregulatory mechanisms effectively compensate for central hemodynamic changes associated with AF.
- These findings suggest AF does not impair resting capillary function in humans.
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.