Subcutaneous Bioimpedance Recording: Assessment of a Method for Hemodynamic Monitoring by Implanted Devices

Abstract

Our findings suggest that closely spaced subcutaneous electrodes identify changes in local tissue/vascular bioimpedance that correlate well with direct invasive measures of induced hypotension in a porcine model.

Assessment of Systolic Ejection Time as a Hemodynamic Marker of Incipient Bradycardic Vasovagal Syncope. A Pilot Study

“…On the other hand, measuring systolic time intervals such as LVET or preejection time 7,9,10 might be much easier and less invasive than measuring blood pressure (BP) by an implantable device for long-term applications. A recent study on subcutaneous impedance also showed clear waveforms corresponding to the aortic pressure waveforms 13 and also this approach could be used to estimate LVET.…”

“…At present, there are no implantable devices equipped with hardware and software capabilities to measure and monitor LVET. Nevertheless, LVET can be estimated by means of accelerometers that detect heart sounds, 7,8 subcutaneous or endocardial impedance, 10,11,13 and other systems could be designed to detect the pulse pressure in peripheral arteries or peripheral perfusion. Nevertheless, additional data are needed to demonstrate the reliability of LVET measurement and tracking through an implantable system.…”

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“…less blood ended up in the brain due to the larger gravitational fi eld in the centrifuge. An additional Gz eff ect that must be taken into consideration is air-blood mismatch in lungs under Gz [3,11,24]. celerations.…”

Remote Monitoring of Patients With Implanted Cardiac Devices

“…28,29 Innovative technology that uses specialized electrodes that measure pectoral muscle bioimpedance has suggested that changes in tissue impedance can provide estimates of systemic blood pressure. 30 …”