Non-invasive monitoring of cardiac contractility and sympathetic drive:
Trans-Radial Electrical Bioimpedance Velocimetry (TREV)
Abstract
We describe methods and software resources for a bioimpedance
measurement technique, “trans-radial electrical bioimpedance
velocimetry” that allows for the non-invasive monitoring of relative
cardiac contractility and stroke volume, proxies of sympathetic cardiac
tone. In addition to describing the general recording methodology, which
requires impedance measurements of the forearm, we provide open source
Jupyter based software (operable on most computers) for deriving cardiac
contractility from the impedance measurements. We demonstrate the
ability of this bioimpedance measurement for tracking event related
contractility in a maximal grip force production task. Critically, the
results demonstrate both a reactive increase in cardiosympathetic drive
with force production as well as a learned increase in drive prior to
grip onset, consistent with allostatic autonomic regulation. The method
and software should be of broad utility for investigations of event
related cardio-sympathetic regulation in psychophysical studies.