Hemodynamics-driven mathematical model of first and second heart sound generation
Fig 5
Relationship between heart rate and amplitudes of S1 and S2.
The amplitudes are normalized to the control. All the experimental data (black dots and lines) are adapted from the figures in the article by Bergman and Blomqvist 1975 [25] in which patients have at least one major coronary artery with reduced vessel diameter by 50%. (a) A linear relationship between S1 amplitude and exercise level in normal condition for both simulation and experiment. (b) Simulated biventricular heart failure causes a reduction in S1 amplitude which is in agreement with the abnormal experimental data. (c) Average of S1 amplitude for both normal and abnormal simulations is within the range of experimental data. (d) Exercise doesn’t change S2 amplitude significantly compared to S1. APO: average of patient observations, BPM: beat per minute, BiVHF1-5: biventricular heart failure levels, HR: heart rate, IPO: individual patient observations, Ref: reference, YNS: young normal subjects.