Fig 1.
(a) Illustration of human arterial system. The picture includes only a few largest arteries; see [19] for the complete set of arteries and veins used in the model. (b) Illustration of human heart including four chambers: left atrium (LA), left ventricle (LV), right atrium (RA) and right ventricle (RV). Left and right ventricular outflow track (lvot/rvot) are short 1D segments before the valves. Valves: tricuspid valve (TV), pulmonary valve (PV), mitral valve (MV) and aortic valve (AV). Picture by BruceBlaus (CC BY).
Fig 2.
(a) Schematic of atrioventriclular (av) model. B is the Bernoulli valve resistance, R is the source resistance, L is the blood inertance and E is the elastance of the wall. The subscripts A and V refer to atrial and ventricular, respectively, and ppc is the pericardiac pressure. (b) Freewall elastance Efw for LA (blue) and LV (black). The figure includes four pulses. The duration of the pulse, the maximum elastance Emax and timing parameters τ1 and τ2 vary between pulses.
Fig 3.
(a) Generic vascular bed model; (b) Hepatic vascular bed model with arterial and venous inlets; (c) Coronary vascular bed model with compartments representing subepicardial, midwall and subendocardial layers.
Table 1.
The sensor locations considered in this work.
xobs is the location of the sensor within the segment and L is the length of the segment.
Fig 4.
Two example pulses with the considered timings marked: the minimum/foot (PTTff; red cross), the maximum (PTTp; green circle), the maximum of the first derivative (PTTD; blue star), and dicrotic notch (DAT; magenta square).
Fig 5.
Distributions of selected metrics for the virtual database (training set; after filtering): (a) heart rate (HR), (b) stroke volume (SV), (c) cardiac output (CO), (d) aortic PWV, (e) mean blood pressure (MBP), (f) pulse pressure (PP), (g) diastolic pressure (DPB), and (h) systolic blood pressure (SPB).
The means of the metrics are shown in the title.
Fig 6.
Accuracy of the aortic PWV predictions using pulse transit time (PTT) measurements from left carotid artery (LCA).
Signals: heart rate (HR) and pulse transit times to the foot of signal (PTTff), peak of signal (PTTp), the point of steepest raise (PTTD), and the dicrotic notch (DAT).
Fig 7.
Accuracy of the DBP predictions using pulse transit time (PTT) measurements from left carotid artery (LCA).
Signals: heart rate (HR) and pulse transit times to the foot of signal (PTTff), peak of signal (PTTp), the point of steepest raise (PTTD), and the dicrotic notch (DAT).
Fig 8.
Accuracy of the SBP predictions using pulse transit time (PTT) measurements from left carotid artery (LCA).
Signals: heart rate (HR) and pulse transit times to the foot of signal (PTTff), peak of signal (PTTp), the point of steepest raise (PTTD), and the dicrotic notch (DAT).