Electrophysiological properties of the atrial myocardium and cardiac conduction system in patients with atrial fibrillation and different comorbidity
Authors: Gorev Maxim V. , Fettser Denis V. , Kovalevskaya Elena A. , Poteshkina Nataliya G. , Urazovskaya Irina L. , Saiganov Sergey A. 
Published: April 2024

BACKGROUND: Atrial fibrillation is a rhythm disorder that has a complex and not yet fully understood etiology and pathogenesis. Catheter ablation is the most effective method for rhythm control in atrial fibrillation patients. The effectiveness of catheter ablation differs in patients with various concomitant pathologies of the cardiovascular system.
AIM: To study electrophysiological properties of atrial myocardium and cardiac conduction system during catheter ablation for atrial fibrillation in patients with different cardiovascular comorbidities.
MATERIALS AND METHODS: Intraprocedural data obtained during primary catheter ablations in 151 selected patients with atrial fibrillation were retrospectively analyzed. The patients were divided into 3 groups based on the presence or absence of cardiovascular comorbid pathology: group 1 — patients with idiopathic atrial fibrillation, group 2 — patients with a combination of atrial fibrillation and isolated essential arterial hypertension, group 3 — patients with a combination of atrial fibrillation and ischemic heart disease.
RESULTS: The ventricular rate in the patients with atrial fibrillation was significantly higher than the heart rate in the patients with sinus rhythm (102.6 ± 20.8 beats/min and 64.9 ± 11.9 beats/min, respectively; p 0.001). The rhythm frequency differed significantly in Group 1, Group 2 and Group 3 in sinus rhythm (61.2 ± 10.9 beats/min, 60.1 ± 8.8 beats/min and 57.2 ± 10.3 beats/min, respectively; р 0.001), and in atrial fibrillation (107 ± 15.8 beats/min, 89.9 ± 14.3 beats/min and 102 ± 12.5 beats/min, respectively; р 0.001). In the patients of all groups both in sinus rhythm and in atrial fibrillation, the heart rate increased after pulmonary vein isolation compared with the rate before ablation (p 0.001). In all groups, after isolation of the pulmonary veins, a statistically significant decrease in the frequency of atrial fibrillatory activity was noted compared to the baseline: by 72 imp/min (р 0.001) in group 1, by 49 imp/min (р 0.001) in group 2, and by 49 imp/min (р = 0.003) in patients of group 3. The frequency of fibrillatory activity after pulmonary vein isolation was comparable in the study groups (р = 0.45), both before and after surgery. In the patients without coronary artery disease, there was a significant decrease in the amplitude of atrial electrograms after ablation compared to preoperative values (р = 0.042 in group 1; p 0.001 in group 2). The effective refractory period of the atrial myocardium did not differ between the groups (235 ± 30.3 ms, 220.6 ± 25.6 ms and 231.2 ± 39.4 ms, respectively; р = 0.359).
CONCLUSIONS: In the patients with atrial fibrillation, the presence of concomitant pathology of the cardiovascular system affects the electrophysiological properties of the myocardium and conduction system of the heart and their changes after pulmonary vein isolation. Additional research is needed to develop a personalized approach to the treatment of atrial fibrillation in patients with concomitant pathology of the cardiovascular system.