Investigations on instantaneous frequency variations of RR time series in intrinsic mode functions of congestive heart failure subjects

The congestive heart failure is a major cause of concern among all types of cardiovascular problems and is attributed to imbalances in sympathetic and parasympathetic nervous systems. In this paper we propose an algorithm for detection of congestive heart failure condition using the variability of instantaneous frequency of intrinsic mode functions obtained using Hilbert-Hunag Transform of RR time series in different subjects. It is observed that the instantaneous frequency of intrinsic mode functions is a key feature that is altered quite significantly with imbalances in autonomic nervous system. It is also observed through simulation results using MATLAB that higher order intrinsic mode functions of RR time series exhibit lower variations of the instantaneous frequency compared to lower order intrinsic mode functions. On the basis of this variability of instantaneous frequency of higher order intrinsic mode functions we are able to detect congestive heart failure condition in different subjects.