Considering the conflicting results, which on the one hand revealed an increase in the relapse rates and severity of atrial fibrillation (AF) symptoms in obese patients and on the other hand revealed the reduced mortality risk and cardiovascular events compared to patients with normal body weight and AF, the problem of studying AF peculiarities in obese patients remains relevant. Based on the Federal State Budget Educational Institution of Higher Education "North State Medical University" of the Ministry of Healthcare of the Russian Federation, Arkhangelsk, the research involving 220 patients with AF and AH was carried out. Inclusion criteria were the newly diagnosed AF form and arterial hypertension in past medical history and at the time of inclusion in the study. The aim of the research was to identify AF peculiarities in overweight and obese patients. BMI was calculated, leptin blood concentration was determined, ECHO was made, and AF paroxysms were detected again by means of ECG. The study showed that patients with AF in obese groups had enlarged left ventricular and left atrium and higher incidence of left ventricular hypertrophy than that of the group with normal body weight. The increase in body weight is associated with an increase in the incidence of AF paroxysm relapses. Leptin concentration is significantly higher in the group of patients with paroxysm relapses. Findings: Obesity causes myocardial remodeling progression and an increase in AF paroxysm relapses. Leptin blood concentration is higher in patients with AF paroxysm relapses.