Autonomic dysfunction in coronary heart disease patients with hemodynamically significant coronary stenoses of varying degrees

It is considered that 0.1 Hz-oscillations in heart rate variability (HRV) are determined by features of the central part of system of autonomic regulation. Aim – to study an influence of the degree of coronary stenosis on 0.1 Hz oscillations in heart rate variability in patients with coronary heart disease (CHD). Methods – 92 patients with CHD associated with stenosis of more then 50% in one or two coronary arteries aged 51±5 years were enrolled in the study. Subgroup of patients with coronary stenosis of more then 75% was singled out (n=78). Rhythmograms at rest and during veloergometric test (VET) with exercise of 25 and 50 Wt were registered during 6 minutes at each stage. The first 3 minutes were registered at spontaneous breathing. The last 3 minutes were registered at controlled breathing with 10 seconds period. Frequency power of HRV spectrum in low-frequency (LF) and in high-frequency (HF) ranges was estimated. It was assumed that the power of LF-range in a parametric spectrum determined by the power of 0.1 Hz oscillations in HRV. Results – the subgroup of patients with CHD associated with coronary stenosis of more then 75% did not differ reliably from the hole group of patients with coronary stenosis of more then 50% neither by absolute values nor by the dynamic of power of LF and HF ranges in HRV spectrum during VET. Conclusions – the degree of autonomic dysfunction associated with hemodynamically significant coronary stenosis does not depend on the further severity of the stenosis.