440
contains the Period of Isovolumic Contraction (PIC), the Period of Rapid Ejection (PRE) and
the real PTT. Some researchers regard PIC and PRE as a whole, which is called the Pre-Ejection
Period (PEP) (Zhang, G. et al. 2011). As shown in Figure 4, PTT_m is about 400 ms; however,
PIC is about 50 ms and PRE is about 100 ms according to a previous study (Yao, T. 2013).
When the aortic pressure rises or myocardial contractility declines, the time of PIC will be
prolonged. It has also been reported that PRE is associated with BP (Yao, T. 2013; Bers, DM.
2001). So, the existence of PIC and PRE affects the accuracy of the model between the BP
and the PTT. For further research, this part should be reconsidered.
6.5 Complicated regulation mechanism ...