Monet wavelet transforms of heart rate variability for autonomic nervous system activity

The aim of this study was to characterize the cardiac autonomic nervous system (ANS) through Monet wavelet transforms of heart rate variability (HRV) and compare to Fast Fourier Transform (FFT) analysis. Cardiac sympathetic and parasympathetic blockades were studied in conscious rats. Monet and FFT were performed in (1) high-frequency band (HF: 0.6 to 3 Hz), (2) mid-frequency band (MF: 0.3 to 0.6 Hz), and (3) low-frequency band (LF: 0.07 to 0.3 Hz). While cardiac sympathetic inhibition with metoprolol did not alter average HR, Monet normalized power indices were able to detect it with the highest level of significance in LF. FFT HRV indices detected only parasympathetic blockade effects in LF and MF of the HRV, which accompanied the increase in the average HR. Thus, alterations of cardiac ANS may be sensitively detected through Morlet wavelet of HRV while average HR is not altered. (C) 2015 The Authors. Published by Elsevier Inc.