Method and system for extracting cardiac parameters from plethysmographic signals

A method for determining cardiac parameters of a subject includes receiving a signal from a thoracocardiograph (TCG) sensor. The signal is sensitive to positions and/or motions of an anterior chest wall of the subject and include a cardiac component, a respiratory component, and noise and/or artifact components. The method also includes receiving one or more electrocardiogram (ECG) signals and filtering the received TCG signal to limit one or more of the respiratory component and the noise and/or artifact components. The filtering includes one or more of wavelet de-noising, non-linear filtering, and state space filtering. The method further includes ensemble averaging the filtered TCG signal. Ensemble members are triggered by occurrence of one or more selected fiducial points determined in the ECG signal. Additionally, the method includes extracting parameters of cardiac functioning from the ensemble averaged signal.