Characteristics of cerebral blood flow and system microcirculation at essential atrial fibrillation
Objective. Examination of the distal blood flow at a regional (middle cerebral artery) and tissular (nail fold vessels) levels of patients with idiopathic atrial fibrillation before surgical treatment with the estimation of relationship between hemodynamic parameters and arrhythmia characteristics such as its form and duration. Material and methods. Study design: open cross-sectional non-randomized study. 102 patients with idiopathic atrial fibrillation (experimental group) and 48 healthy persons (control group) were included in to the study. The blood flow in the middle cerebral artery was studied with ultrasonograph «Vivid 7 Dimension» (GE Healthcare, USA) and «iE33» (Philips, Netherlands), and in the nail fold vessels – with the help of device «Minimax-Doppler-K» (Russia). Mean blood flow velocity and pulsatility index were evaluated. During the analysis of hemodynamic parameters the patients of the experimental group were divided into subgroups, taking into consideration following factors: cardiac rate (atrial fibrillation with fast and normal ventricular rate, sinus rhythm), duration of atrial fibrillation (more or less than 5 years), age of patients (over or under 50 years old). The data received were processed statistically with the help of Statistica 8.0 software. Results. In patients of experimental group with atrial fibrillation with fast ventricular response, duration of atrial fibrillation more than 5 years and at the age over 50 years old values of mean blood flow and pulsatility index differed significantly compared to the standard parameters at the level of nail fold vessels.The difference of the specified parameters compared to standard values, taken as 100 %, was 15 % to 30 %. In patients with normal ventricular response during atrial fibrillation, with sinus rhythm, duration of atrial fibrillation less than 5 years and age under 50 years old the difference between tested parameters of blood flow at the level of nail fold vessels and standard values was non-significant. The measured parameters of blood flow at the level of middle cerebral artery in patients of the experimental group did not differ significantly from the control of any other sub-groups, considering cardiac rhythm, duration of arrhythmia and age of the patients. Conclusion. Idiopathic atrial fibrillation is associated with the abnormalities of microcirculation, but not at the regional level in the middle cerebral artery. Abnormalities of tissular blood flow are significant in patients with fast ventricular rate, duration of the disease over 5 years and age over 50 years old. Obviously, for the prediction of hemodynamic stroke in patients with atrial fibrillation it is useful to estimate the tissular blood flow at the level of microvessels of nail fold.