Hemodynamics-driven mathematical model of third heart sound generation

Area of Science:

• Cardiovascular Physiology
• Biomedical Engineering
• Computational Cardiology

Background:

• The third heart sound (S3) is a proto-diastolic sound linked to various hemodynamic states in healthy and diseased hearts.
• Understanding S3 generation is crucial for diagnosing and prognosing cardiac conditions.

Purpose of the Study:

• To develop and validate a novel mathematical model for simulating S3 vibrations.
• To investigate the key factors influencing S3 generation across different cardiovascular conditions.

Main Methods:

• A one-degree of freedom mathematical model of heart and blood mechanical vibrations was created.
• The model was implemented in the real-time cardiovascular system simulator, CircAdapt.
• Simulations were conducted for normal heart function and conditions including heart failure with preserved ejection fraction (HFpEF), atrioventricular valve regurgitation (AVR), atrioventricular valve stenosis (AVS), and septal shunts (SS).

Main Results:

• Simulated S3 exhibited strong qualitative and quantitative agreement with measured S3 in morphology, frequency, and timing.
• Ventricular mass, viscoelastic properties, and inflow momentum were identified as critical for S3 generation.
• S3 intensity increased in HFpEF, AVR, and SS, correlating with cardiac output and disease severity, while AVS showed less significant acoustic changes.
• S3 vibrations were consistently generated in both left and right heart sides, varying in audibility.

Conclusions:

• The developed hemodynamics-driven mathematical model offers fast and realistic S3 simulation.
• This model can potentially identify novel indicators for the diagnosis and prognosis of cardiac diseases.
• The study highlights the universal presence of S3 vibrations across various cardiac states.