HEART RATE VARIABILITY IN PATIENTS WITH METABOLIC SYNDROME AND HEART FAILURE WITH PRESERVED EJECTION FRACTION

Background. The development of life-threatening rhythm and conduction disorders occupies a special place in the mortality structure of patients with chronic heart failure with preserved ejection fraction (HFpEF). Therefore, an accessible, non-invasive marker is needed to stratify the risk of adverse arrhythmogenic events in individuals with this pathology. The possibility of using heart rate variability (HRV) parameters for this purpose is of great interest. Aim. To study the time domain parameters of heart rate variability, as well as to perform a correlation analysis of the HRV data obtained with echocardiography indicators in patients with metabolic syndrome and heart failure with preserved ejection fraction. Material and methods. The study included 130 patients (75 women and 55 men), whose average age was 65.9±5.8 years. Three study groups were formed, represented by patients with heart failure with preserved ejection fraction and criteria of metabolic syndrome (MS), IDF, 2005: two-component MS and HFpEF (n=30), three-component MS and HFpEF (n=30), HFpEF without MS (n=30). The control groups included individuals with MS, but without signs and/ or symptoms of heart failure (n=20), as well as practically healthy (n=20). The complex of examinations included taking anamnesis, physical and general clinical laboratory examinations, echocardiography and Holter monitoring of the electrocardiogram. Results. Patients with HFpEF according to echocardiography differ significantly higher values of the ratio E/e' med, lat (p <0.0001), pulmonary arterial systolic pressure (p<0.01), as well as the rate of tricuspid regurgitation peak velocity (p<0.01). Significant differences in the parameters of relative wall thickness and left ventricular mass index (p<0.05) were recorded in the groups with concomitant MS and HFpEF. The analysis of daily HRV values demonstrated a decrease in the parameters of general vegetative tone and sympathetic link. However, significant differences were obtained only in the groups with MS and HFpEF (SDNN p<0.05, SDNNi p<0.05, SDANN p<0.01). The same pattern of changes is recorded both during the day and at night parameters HRV (SDNN, SDNNi, SDANN p<0.05). The most significant correlations between HRV and echocardiography parameters were found only in patients with three-component MS and HFpEF (left atrial volume index and SDNN (r=-0.47, p=0.013), SDANN (r=-0.54, p=0.004), ejection fraction and SDNN (r=-0.5, p=0.009), SDANN (r=-0.44, p=0.02), SDNNi (r=-0.42, p=0.03) and left ventricular mass index and SDNNi (r=0.47, p=0.01)). Conclusions. Heart rate variability in the time domain in patients with HFpEF are characterized by a decrease in a number of indicators. The addition of metabolic syndrome, as well as an increase in the number of its components, have the most depressing effect on HRV values in individuals with this phenotype of heart failure.