Selective quantification of cardiac sympathetic and parasympathetic nervous function from non-invasive measurements

Power spectral analysis of spontaneous heart rate (HR) variability is a popular and convenient technique for quantifying cardiac autonomic nervous function. While this technique can provide an effective index of parasympathetic nervous function, it cannot provide a pure index of A -sympathetic nervous function. We have developed a non-invasive technique for selectively quantifying cardiac sympathetic and parasympathetic nervous function by employing a multi-signal approach in conjunction with prior physiologic knowledge. We have tested the technique in 14 human subjects under pharmacological autonomic blockade, and our results show that the technique can substantially outperform traditional HR power spectral indices in terms of predicting the known drug effects.