Figure 1.
(a) electrical representation, (b) schematic representation of the lumped parameter model used to simulate left-sided heart in presence of aortic stenosis and/or systemic arterial hypertension. LV: left ventricle, AS: aortic stenosis, Elv(t): normalized time-varying elastance (please see Table 1 for all other parameters used in the lumped parameter model).
Table 1.
Summarized cardiovascular parameters used to simulate all cases.
Table 2.
Baseline characteristic data.
Figure 2.
LV stroke work and N-SW.
Figure 3.
Comparison of simulated and CMR flow waveforms.
(a) healthy subject, (b) patient with mild AS, (c) patient with moderate AS, (d) patient with sever AS.
Figure 4.
Correlation between results based on TTE and CMR measurements.
(a) correlation between computed normalized left ventricular stroke works based on parameters measured by TTE and CMR, (b) correlation between computed valvulo-arterial impedance based on parameters measured by TTE and CMR.
Figure 5.
Correlation between normalized left ventricular stroke work and valvulo-arterial impedance.
both computed using the lumped parameter model based on the parameters measured by (a) TTE and (b) CMR.
Figure 6.
Dependency of valvulo-arterial impedance to effective orifice area and stroke volume.
(a) as a function of effective orifice area (EOA), (b) as a function of stroke volume for normal arterial pressure.
Figure 7.
Dependency of normalized left ventricular stroke work to effective orifice area and stroke volume.
(a) as a function of effective orifice area (EOA), (b) as a function of stroke volume for normal arterial pressure.
Figure 8.
Valvulo-arterial impedance and normalized left ventricular stroke work.
(a) Valvulo-arterial impedance () as a function of stroke volume, (b) normalized left ventricular stroke work (N-SW) as a function of stroke volume. In both panels a subset of patients with low flow and low pressure gradient conditions (Table 2) were considered. In these patients, AS was either moderate (EOA = 1.48 cm2, n = 4) or severe (EOA = 0.85 cm2, n = 5). In both groups, the stroke volume index (SVi) was less than 35 ml/m2 and the transvalvular pressure gradient was less than 20 mmHg. Both
and N-SW were computed using the lumped parameter model based on the parameters measured by CMR.