Persistent left superior vena cava in a patient with an implanted dual-chamber pacing system in atrial fibrillation with tachycardia-bradycardia syndrome.

The relevance of the study is conditioned by the problem of implantation of an artificial cardiac pacemaker in atrial fibrillation in patients with tachy-brady syndrome according to the standard scheme related to the presence of a congenital anomaly, such as persistent left superior vena cava. The purpose of the study is to develop an operative method of implantation of a permanent two-chamber pacemaker in patients with tachy-brady syndrome with concomitant pathology of the persistent left superior vena cava. Research methods are the generally accepted clinical and instrumental examination of the patient, including taking anamnesis and a standard cardiological examination, electrocardiography, transthoracic echocardiography, plain radiography, angiocardiographic examination, and multispiral computed tomography, which, along with a general analysis, confirm the presence of tachy-brady syndrome with atrial fibrillation and congenital anomaly in the form of persistent left superior vena cava in patients. The study presents a developed model of surgical implantation of a permanent two-chamber pacemaker to stabilise the condition of patients with atrial fibrillation related to tachy-brady syndrome with concomitant persistent left superior vena cava; the standard implantation mechanism included the introduction of a radiopaque agent to clarify the anatomical structure of the vascular bed, further, its entry from the subclavian veins into the persistent left superior vena cava and into the cavity of the right atrium through the venous coronary sinus was detected, and then a gradual introduction of an endocardial right ventricular electrode was performed into the subclavian vein through the tricuspid valve along with its further positioning in the apex of the right ventricle; therefore, a permanent two-chamber pacemaker can be successfully installed, creating conditions for restoring sinus rhythm in this group of patients, which is of practical importance for the field of medicine (Tab. 3, Fig. 4, Ref. 20). Keywords: atrial fibrillation, persistent left superior vena cava, sick sinus syndrome, pacemaker implantation, cardiac surgery.

Atrial fibrillation: Epidemiology, pathophysiology, and clinical complications (literature review).

The last three decades have been characterized by an exponential increase in knowledge and advances in the clinical management of atrial fibrillation. The purpose of the study is to provide an overview of the pathogenesis of nonvalvular atrial fibrillation and a comprehensive investigation of the epidemiological data associated with various risk factors for atrial fibrillation. The leading research methods are analysis and synthesis, comparison, observation, induction and deduction, and grouping method. Research has shown that old age, male gender, and European descent are important risk factors for developing atrial fibrillation. Other modifiable risk factors include a sedentary lifestyle, smoking, obesity, diabetes mellitus, obstructive sleep apnea, and high blood pressure predisposing to atrial fibrillation, and each has been shown to induce structural and electrical atrial remodeling. Both heart failure and myocardial infarction increase the risk of developing atrial fibrillation and vice versa creating feedback that increases mortality. The review is a comprehensive study of the epidemiological data linking nonmodifiable and modifiable risk factors for atrial fibrillation, and the pathophysiological data supporting the relationship between each risk factor and the occurrence of atrial fibrillation. This may be necessary for the practice of the treatment of the cardiac system.