The aim was to analyze the presence of clinical manifestations of anxiety, the frequency of cardiac arrhythmias and to investigate the effectiveness of pregabalin in patients with arterial hypertension (AH), ischemic heart disease (IHD) and in military personnel with acute myocarditis (AM). Materials and methods. The study included 172 male patients with cardiovascular diseases: 102 of them were military personnel with AM; 35 patients with AH, 35 patients with IHD. The patients did not have clinically pronounced signs of heart failure and had preserved ejection fraction according to echocardiographic examination. All patients were surveyed using the HADS (Hospital Anxiety and Depression Scale) and the Hamilton scale (HAM-A) to determine the presence and severity of anxiety. Patients with clinically significant anxiety were prescribed pregabalin (Zonik, LLC «Gladpharm LTD») 75 mg twice daily for 2 months, after which a repeated questionnaire and examination were performed. All patients also had serum cortisol levels and 24-hour electrocardiogram monitoring at baseline and 2-month follow-up. Results. In military personnel with AM, compared with patients with AH and IHD, clinical manifestations of anxiety were detected 30.4 and 24.5% more often, respectively, and were associated with a more pronounced violation of heart rhythm variability (according to the SDNN index and LF/HF ratio, which were 20.0% and 23.3% lower compared with those in patients with AH; as well as a 21.3% lower LF/HF ratio compared with patients with IHD) and with a more frequent development of supraventricular extrasystole and atrial fibrillation without association with ventricular arrhythmias. The use of pregabalin in military personnel with acute myocarditis, for 2 months, led to a decrease in the number of points according to the results of the assessment on the HADS scale by 1.85 times and on the HAM-A scale by 1.63 times, which corresponded to the absence of an anxiety disorder and was accompanied by normalization of cortisol levels. At the same time, a decrease in the frequency of supraventricular extrasystole by 39.5% and paroxysms of atrial fibrillation by 34.5% was found on the background of an improvement in the sympathovagal balance, as evidenced by an increase in the LF/HF index by 22.5%. Conclusion. Patients with acute myocarditis were characterized by more pronounced manifestations of anxiety compared to patients with hypertension and ischemic heart disease and a more frequent presence of cardiac arrhythmias. The use of pregabalin for 2 months led to the elimination of clinical manifestations of anxiety in all groups of patients, and in patients with myocarditis it was associated with a decrease in the frequency of supraventricular arrhythmias.