Methods and apparatus for utilizing multiple sources of physiologic data to enhance measurement robustness and accuracy. In one embodiment, phonocardiography or “heart sounds” data is used in combination with one or more other techniques (for example, impedance cardiography or ICG waveforms, and/or electrocardiography or ECG waveforms) to provide more accurate and robust physiological and/or hemodynamic assessment of living subjects. In one variant, the aforementioned methods and apparatus are used to improve ICG fiducial point (e.g., B, C and X point) detection and identification accuracy. Moreover, the new ICG fiducial points that may be clinically important may be identified using the disclosed methods and apparatus. In a further aspect, the invention discloses methods and apparatus for utilization of ICG and/or ECU waveform information to improve the identification and characterization of heart sounds (such as e.g., S1, S2, S3, or S4 heart sounds), murmurs, and other such artifacts or phenomena.
