Parametric analysis of flow in the intramyocardial circulation

Area of Science:

• Cardiovascular Physiology
• Biomedical Engineering
• Mathematical Modeling

Background:

• Understanding intramyocardial circulation is crucial for diagnosing and treating coronary artery disease.
• Existing models often simplify the complex interplay of factors affecting coronary blood flow.

Purpose of the Study:

• To develop and utilize a simple mathematical model for a better understanding of intramyocardial circulation and coronary blood flow.
• To investigate the significance of key parameters governing coronary blood flow dynamics.

Main Methods:

• A three-layer mathematical model of the intramyocardial circulation was employed.
• Each layer was characterized by a three-parameter Windkessel model (capacitance and two resistances).
• The model incorporated the effects of the beating heart (intramyocardial pump) and vessel collapse (elevated backpressure).

Main Results:

• The model identified three critical parameters: normalized time constant (tau), total resistance (Rt), and resistance distribution (alpha).
• Both normal beating heart and prolonged diastole scenarios were analyzed.
• Calculated pressure-flow relationships and zero-flow pressures demonstrated high sensitivity to tau and alpha during prolonged diastole.

Conclusions:

• The developed mathematical model provides valuable insights into intramyocardial circulation.
• The parameters tau and alpha are particularly significant in determining coronary blood flow characteristics, especially under conditions of prolonged diastole.
• This model can aid in understanding the physiological basis of coronary blood flow regulation.