A selective quantification of cardiac sympathetic and parasympathetic control and its validation through pharmacological blockade

A quantitative evaluation of parasympathetic and sympathetic function is @en desirable in clinical practice. We previously proposed a noninvasive method to selectively quantify cardiac sympathetic and parasympathetic control. This method involves system identijkation analysis of the coupling mechanism between the instantaneous lung volume and heart raie signals. In the present study, we validated this method in conjunction with a newly developed Weighted Principal Component Regression-based system identification technique. We utilized data collected from 14 subjects in the control and autonomic blockade conditions in the standing posture. The results showed that a statistically signifcant reduction in parasympathetic function and sympafhetic function was identified when atropine or propranolol was adminisiered, respectively, and with autonomic double blockade, consistent with the wellaccepted physiologic knowledge.