Indicators of heart rate variability and left ventricular deformation parameters in patients with hypertension in combination with left ventricular diastolic dysfunction

BACKGROUND: Currently, there is little data on changes in the parameters of heart rate variability and the appearance of subclinical systolic dysfunction of the left ventricular myocardium in hypertensive patients with the development of diastolic dysfunction.

AIM: To study indicators of heart rate variability and parameters of left ventricular deformation in patients with hypertension depending on the presence of diastolic dysfunction.

MATERIAL AND METHODS: 60 patients with stage I–II hypertension (28 women and 32 men) who were in the cardiology department of the clinical hospital and 30 healthy volunteers (23 men and 7 women) were examined. The mean age of the patients was 42±9.4 years, the age of healthy volunteers was 41.3±3.5 years. All subjects underwent Holter monitoring, echocardiographic determination of left ventricular diastolic dysfunction and global deformity. According to the presence of diastolic function of the left ventricle, patients with hypertension were divided into two groups: the first group included 30 patients without impaired diastolic function of the left ventricle according to the results of echocardiography, the second group included 30 patients with diastolic dysfunction, the third group (control) consisted of healthy volunteers. Correlation analysis was performed using the Spearman test. To compare two samples of continuous independent data, the Mann–Whitney U-test was used with the correction of the obtained p-values using the Benjamin–Hochberg test due to the multiple comparison procedure.

RESULTS: When studying heart rate variability, it was found that the power in the high frequency range in patients of the first group was reduced by 2.1 times compared with the control (p=0.0087), in patients of the second group — by 3.4 times compared with healthy people (p=0.005). An imbalance of vegetative influences and a tendency to increase the balance of sympathetic and parasympathetic activity were found. In the study of the average value of the global deformation, it was found that it is lower by 41% in the second group, and in the third - by 48% compared with the control group (p=0.01 and p=0.0002, respectively). The mean values of the global strain were associated with a decrease in the standard deviation of the values of the normal R–R intervals (r=0.60, p=0.0001), and the end-systolic and diastolic volumes were correlated with the LH/HF index (r=0.51, p=0.0021 and r=0.65, p=0.001, respectively).

CONCLUSION: Heart rate variability and indicators of left ventricular deformation in patients with hypertension are reduced in the presence of its diastolic dysfunction.