Abstract
Non-Gaussianity of heart rate variability (HRV) has been reported to be a predictor of mortality in patients with chronic heart failure (CHF) and in patients after acute myocardial infarction. In those studies, non-Gaussianity index observed at the coarse graining scale of 25s was an independent significant predictor of mortality. To explain the physiological mechanism generating such non-Gaussianity, it has been suggested that non-Gaussian behavior of HRV is related to sympathetic overdrive. However, no correlation between the non-Gaussianity index and conventional frequency domain indices, such as high-frequency (HF) power, low-frequency (LF) power and LF/HF ratio, was observed. In this study, we focus on amplitude modulation of LF and HF oscillating component of HRV, and show that the non-Gaussianity of HRV as a mortality predictor correlates mainly with the amplitude variation of the LF oscillating component. In addition, it is also shown that increased heterogeneity of LF amplitude modulation is a significant mortality predictor in CHF patients (n=108).
