Aim. To study orthogonal electrocardiography (ECG) parameters among arterial hypertension (AH) patients, in regard to renin-angiotensin-aldosterone system (RAAS) functional status. Material and methods. The study included 41 AH patients, mean age 45±2.8 years, and control group of 41 healthy individuals, mean age 41±7 years. Plasma aldosterone concentration (PAC) and plasma rennin activity (PRA) were measured at rest and after 4-hour walking. In all participants, 12-lead ECG and orthogonal ECG were registered, assessing left ventricular hypertrophy (LVH) criteria: Sokolow-Lyon criterion, Cornell index, Rx+Sz summary index, and repolarization acceleration vector module (G). Results were compared with echocardiography (EchCG) signs of LVH. Results. All patients had low-renin AH with various PAC levels. Three groups were identified: Group I (n=16), with adrenal cortex aldosteroma; Group II (n=12), with adrenal cortex hyperplasia; Group III (n=13), with normal PAC and no adrenal pathology. Comparing to Groups II and III, Group I had higher levels of systolic and diastolic blood pressure (BP), as well as more pronounced hyperaldosteronemia and hypokaliemia (p<0.05). Mean Cornell index in Group III was significantly lower than in Group I: 1.6±0.2 vs 2.5±0.2 mV, respectively. G index in Group III (71±9 ms) was significantly greater than in Groups I (35±5 ms) or II (47±6 ms). Inter-group differences for other parameters were not observed. Conclusion. Patients with adrenal cortex aldosteroma had significantly higher BP levels, more pronounced hyperaldosteronemia, hypokaliemia, and ECG signs of LVH, comparing to Groups II or III
