Echocardiographic changes and cardiac adaptation to physical loads in employees of special units of the Ministry of Internal Affairs and the National Guard of Russia.

Background: Employees of special units of the Ministry of Internal Affairs and the National Guard of Russia are exposed to intense physical loads, which require high endurance and cardiovascular adaptation. However, such adaptation may mimic pathological conditions, such as cardiomyopathies, complicating differential diagnosis. This study aimed to investigate echocardiographic changes and cardiac adaptation in these individuals compared to a control group. Methods: The study included 37 male employees of special units (mean age 38 6 years) with regular physical activity of at least 15 hours per week and 33 age- and BMI-matched controls (mean age 37 7 years) without regular exercise. All participants underwent electrocardiography (ECG) and transthoracic echocardiography (TTE). Left ventricular (LV) dimensions were measured using the Teichholz method, and systolic function was assessed using the modified Simpsons biplane method. Statistical analysis was performed using Statistica v. 6.0. Results: In the main group, 48% had sinus bradycardia (heart rate 60 bpm), and 8% had incomplete right bundle branch block. Echocardiography revealed significantly larger LV end-diastolic dimensions (57.5 [48; 61] mm vs. 51 [47; 56] mm, p 0.05) and right ventricular (RV) basal dimensions (45.5 [37; 49] mm vs. 37.5 [33; 42] mm, p 0.05) compared to controls. LV ejection fraction was within normal limits in both groups (59.5 [54; 62]% vs. 60.4 [53; 61]%). Signs of RV and left atrial dilation were observed in 56.7% and 13% of the main group, respectively. No significant valvular pathologies were detected. Conclusion: Employees of special units exhibit echocardiographic changes consistent with volume load adaptation, including chamber dilation and increased LV mass index.