Bradysystole in permanent atrial fibrillation: clinical importance and modeling in experiment

Aim – to determine additional risks of developing arterial thrombotic and thromboembolic complications in bradysystolic AF and substantiate the results using modeling of intra-arterial hemodynamics. Material and methods. A single-center prospective study involving 252 patients: 146 in the main group, 106 in the control group. The main group was divided into 2 subgroups: 1A subgroup RR ECG interval 1.5 seconds; 2B subgroup RR≥1.5 seconds. A comprehensive examination of the patients was carried out. The second stage is prospective comprising an analysis of the development of arterial thrombotic and thromboembolic complications over 1 year. Experimental modeling was carried out using the “Device for simulating intra-arterial circulation”. Results. Thrombotic and thromboembolic complications were more common in subgroup 1B (OR=8.287 (2.287; 30.040); z=3.219; p=0.001). When analyzing the main parameters of the hemodynamics of the main arteries, the first pulse wave, coming after a long pause of 1.5 seconds or more in AF, was accompanied by a statistically significant increase in all of analyzed parameters. In the experiment, when simulating AF, the intensity of the mechanical impact of the free end of the thread on the wall of the rotameter was maximum when the pause between pulse waves was 1.5 seconds or more (9.70 ± 2.52 mm). At this moment, the piezocrystalline pressure sensor recorded the maximum increase in pressure inside the rotameter tube by an average of 56%. Conclusions. Bradysystole in AF is associated with a significantly higher likelihood of developing long-term thromboembolic events. The first pulse wave, coming after a long pause between ventricular contractions during AF, leads to a significant increase in the main parameters of the hemodynamics of the main arteries (linear velocity of blood flow, volumetric blood flow). When monitoring heart rate in AF, it is necessary to avoid bradysystole with pauses between ventricular contractions of 1.5 seconds or more, due to a higher risk of stroke, myocardial infarction, and distal arterial embolism in other vascular regions.