Correlation between heart rate variability and severity of coronary atherosclerosis: Looking for non-invasive indicators of the disease severity

BACKGROUND Although heart rate variability (HRV) has been shown to be altered among patients with ischemic heart disease (IHD), studies on relationships between HRV indices and angiographic severity of IHD give conflicting results. Additionally, a plethora of mathematical models have been established, offering a novel approach for analyzing HRV. AIM To analyze correlations between angiographic severity of coronary atherosclerosis and a wide spectrum of HRV indices in patients with stable IHD. METHODS Total of 139 consecutive patients with stable IHD scheduled for coronary angiography were enrolled. Angiograms were scored using the method of Gensini. Five-minute electrocardiogram readings were analyzed. Correlations between the Gensini score and HRV indices were tested. RESULTS The study did not reveal statistically significant correlations between Gensini score and traditional HRV indices (standard deviation of NN intervals, root mean square of successive differences, spectral indices). The angiographic severity of coronary atherosclerosis assessed using the Gensini score was correlated with the following HRV indices: Van Geijn interbeat interval difference (r = -0.232; P < 0.05), de Hann sinus tachycardia index (r = -0.227; P < 0.05), Huey long-term variability (r = -0.167; P < 0.05), and Dalton mean absolute beat-to-beat (r = -0.169; P < 0.05). CONCLUSION Traditional time and frequency domain HRV indices do not correlate with angiographic severity of IHD. Several novel HRV parameters merit more attention as they weakly correlated with the Gensini score in stable IHD patients. Further research exploring relationships between angiographic severity of IHD and HRV indices is warranted.