Aim: To investigate the specific features of a 24-hour blood pressure (BP) profile and heart rate variability (HRV) in the indigenous peoples (Nenets, Khanty, Selcups, and Komis) and newcomers with chronic coronary heart disease (CHD) and hypertension, who lived in the Yamal-Nenets Autonomic District.
Subjects and methods: Two hundred male and females patients aged 21 to 55 years (mean age 48.2 +/- 0.7 years) with chronic CHD and hypertension, who resided in the Far North, were examined. All the patients were divided into 4 groups: (1) 50 aboriginal patients with hypertension only; (2) 50 newcomers with hypertension only; 3) 50 natives with chronic CHD and hypertension; (4) 50 non-natives with the above conditions. The groups were matched for gender, age, and the duration of hypertension and CHD. To study the nature of changes in the 24-hour BP profile, all the patients underwent 24-hour ambulatory BP monitoring (ABPM) and HRV examination.
Results: The HRV analysis revealed that all the groups had increases in sympathetic autonomic nervous system (ANS) activity (88% in Group 1; 96% in Group 2; 94% in Group 3, and 92% in Group 4) and decreases in parasympathetic ANS activity (76% in Group 1; 74% in Group 2; 78% in Group 3; and 72% in Group 4), which was suggestive of neurocardiopathy. Analyzing the data of 24-hour ABPM showed that among the natives, there were more patients with increased systolic and diastolic BP (SBP and DBP) variability and higher nocturnal SBP time index (TI). These groups also showed a preponderance of patients with abnormal 24-hour BP profiles as compared to the groups of newcomers (p = 0.034). Among the latter, there were more patients with higher SBP and DBP variability and increased daytime DBP TI and also more patients with a normal nocturnal BP reduction (p = 0.012).
Conclusion: The group of indigenous populations displayed a predominance of non-dippers and night-pickers and higher nocturnal SBP and DBP whereas the group of non-indigenous ones exhibited a preponderance of dippers and higher daytime SBP and DBP variability.