Time Relationships in the Cardiac Cycle

Although flie interpretation of the amplitude of the ICG is obscured by many complicating factors, a more relevant aspect of the ICG signal may be found in the time relationships, especially when the timing of specific marker points in the ICG signal is compared with that of marker points in the ECG. Regardless of the multiple sources of the signal, the ICG reflects the mechanical/hydrodynamical aspects of the cardiac cycle, as described by 

as can be expected because this strongly influences the preload of the heart (Meijer et al., 2010). 

Most of the problems encountered in ICG, such as uncertainty about the distribution of the electrical field and dependence on electrode position, concern an influencing of the impedance signal by amplitude modulation. The timing, however, of the points and waves in the ICG signal is mostly independent of these problems. Therefore, the use of the time relationships instead of the amplitude of the ICG offers more fruitful perspectives for clinical and physiological applications. The method is noninvasive, without adverse 

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