engleski

Leftward shift of heart rate variability spectral sympathetic central frequency by a progression of cardiac disease

Background: Ratio between low and high frequency components (LF/HF ratio) of heart rate variability (HRV) computed on 24 hour Holter recordings seems inadequate to describe autonomic control of sinus node in most patients with cardiac disease. Objective: To test the hypothesis that progression of cardiac disease decreases frequency of autonomic oscillations and shifts the centre frequency of some HRV spectral components leftward. Study population: 710 cardiac patients and 185 healthy subjects. Patients were divided by age, gender, history of cardiac surgery or myocardial infarction, left ventricular systolic function and total HRV. Interventions: 24-hour Holter recordings were used for HRV analyses. The ratio between very low and low frequency spectra (VLF/LF ratio) was used instead LF/HF ratio in patients with advanced cardiac disease and marked reduction in HRV. Results: With the use of VLF/LF ratio as an alternative measure of autonomic modulation of sinus node in patients with decreased HRV, an increase of this index in accordance with the clinical extent of sympathetic activation and with the progression of a disease, was observed. As a rule, the lower the HRV, the higher the VLF/LF ratio (corr. coeff. were - 0.26 for standard deviation of all normal RR intervals and - 0.33 for total power ; p< 0.01 for both). Conclusion: Results support the thesis that the disease progression shifts the central frequency of sympathetic spectral component toward lower values.

heart rate variability; autonomic nervous system; cardiac disease

nije evidentirano