Electrical cardioversion for atrial fibrillation improves microvascular flow independent of blood pressure changes

Objective: This study tested the hypothesis that there is a discrepancy between global hemodynamic parameters and microvascular flow in patients before and after successful elective electrical cardioversion (ECV) for atrial fibrillation (AF). Design: Prospective observational study. Setting: Preanesthesia holding area in a teaching hospital. Participants: Adult patients who underwent successful elective ECV for AF. Interventions: ECV. Measurements and Main Results: Routine measurements of heart rate and noninvasive blood pressure were recorded and the sublingual microcirculation was visualized by sidestream darkfield imaging before and after the conversion of AF to sinus rhythm by elective ECV. The conversion to sinus rhythm significantly improved the microvascular flow index for smaller and larger microvessels. For smaller microvessels, perfused vessel density did not reach significance after conversion to sinus rhythm, whereas the proportion of perfused vessels was significantly larger and indices of heterogeneity for microvascular flow index decreased significantly. No correlation could be identified for the changes in mean blood pressure, perfused vessel density, and microvascular flow index for smaller microvessels. Conclusions: Successful ECV in patients with AF improves indices of sublingual microvascular perfusion. This change has no clear relation to the change in blood pressure and cannot be predicted from it. It may be prudent not to rely solely on global hemodynamic parameters to assess end-organ perfusion in this setting.