Accurate, noninvasive hemodynamics have been the Holy Grail sought for two decades. When conventional impedance cardiology appeared, many felt the goal has been achieved, only to be disappointed by the limitations that quickly became apparent:
Poor correlation to invasively-determined values
Inaccuracies during motion artifact
Over the last two decades, conventional (Z0-based) ICG has been improved and tweeked, but has never overcome its basic dependence on determining the initial thoracic impedance. To solve the problem, impedance cardiology was reinvented to be independent of baseline thoracic impedance (Z0).
The breakthrough that accomplished this was to use the impedance signal's morphology (waveform), instead of its baseline value, a patented-approach called Signal-Morphology Impedance Cardiology (SM-ICG™). The novel technology received FDA-clearance and was introduced to the U.S. market by Neumedx in PhysioFlow®