RELATIONSHIP BETWEEN HEART RATE VARIABILITY AND LEFT VENTRICULAR EJECTION FRACTION IN PATIENTS WITH CORONARY HEART DISEASE AND CHRONIC HEART FAILURE

Highlights The study deepens the understanding of the relationship between HRV and LV in patients with coronary heart disease and CHF, which may contribute to a more accurate diagnosis and classification of the severity of the disease. Determining the average VLF power values allows using this indicator for early diagnosis of neurohumoral disorders. The study highlights differences in vegetative balance in patients with different levels of HF, which may help in the development of more effective approaches to the treatment of CHF. Abstract Aim . To determine the relationship between heart rate variability indices and left ventricular ejection fraction in patients suffering from coronary heart disease with chronic heart failure. Methods . The study included 94 outpatients (47 men and 47 women) with coronary heart disease and chronic heart failure, aged 42 to 83 years. According to the classification of chronic heart failure, depending on the left ventricular ejection fraction, the patients were divided into groups: Group 1 (CHFpEF) – preserved EF (≥ 50%), Group 2 (CHFmrEF) – moderately reduced EF (41–49%); Group 3 (CHFrEF) – reduced EF (≤ 40%). The ejection fraction was determined based on the results of echocardiography (using the Simpson method), and the heart rate variability indices were calculated based on the data of Holter ECG monitoring. The dependence of quantitative indices of the heart rate variability power and the left ventricular ejection fraction (%) was also analyzed. Result . In groups of patients with a lower left ventricular ejection fraction, a significantly lower value of the power of temporal (SDNN, SDANN) and spectral (VLF) indices of heart rate variability was noted (p < 0,05). In group 1 (CHFpEF), the nHF power (22 ± 9) was higher than in group 2 (CHFmrEF) (17 ± 5). However, in group 3 (CHFrEF) (40 ± 27), the nHF power demonstrated significantly higher values ​​than in groups 1 and 2. At the same time, in group 3, a very low value of HF, VLF and LF powers was revealed relative to groups 1 and 2. A quantitative analysis of the left ventricular ejection fraction (%) relative to the power of the spectral indices of heart rate variability revealed a noticeable direct correlation with VLF (r = 0,617; p < 0,001). Quantitative statistical assessment of the power of time indices of heart rate variability and left ventricular ejection fraction (%) revealed a direct correlation for avNN (r = 0,207; p = 0,046), SDNN (r = 0,304; p = 0,003), SDNNidx (r = 0,213; p = 0,039), SDANN (r = 0,296; p = 0,004). Conclusion . In patients with coronary heart disease, a decrease in the overall power of heart rate variability is associated with the severity of chronic heart failure by left ventricular ejection fraction. The autonomic balance in different groups of chronic heart failure by left ventricular ejection fraction is different. Thus, group 1 (CHFpEF) of patients was characterized by heart rate variability power indicators, which indicated a slight deviation in the balance of the autonomic nervous system. In group 2 (CHFmrEF), heart rate variability indicators characterized sympathicotonia. In group 3 (CHFrEF), the predominance of the parasympathetic division of the autonomic nervous system was revealed (p < 0,05). The average values ​​of VLF power (ms 2 ) were determined, which can be used for early diagnosis and classification of the severity of neurohumoral disorders in CHF: CHFpEF – 1622 ± 417; CHFmrEF – 1059 ± 307; CHFrEF – 589 ± 152 (p < 0,001).