Left ventricular interaction with arterial load studied in isolated canine ventricle

Area of Science:

• Cardiovascular Physiology
• Biomechanical Engineering
• Computational Biology

Background:

• Understanding stroke volume (SV) regulation is crucial for diagnosing and treating cardiovascular diseases.
• The mechanical interaction between the left ventricle and the arterial system significantly influences SV.
• Existing models often simplify this complex ventriculoarterial coupling.

Purpose of the Study:

• To develop and validate an analytical framework for predicting stroke volume (SV) based on ventriculoarterial mechanical interactions.
• To characterize the left ventricle and arterial system using end-systolic pressure (Ps)-SV relationships.
• To establish a predictive formula for SV incorporating ventricular and arterial properties.

Main Methods:

• Developed a framework analyzing the end-systolic pressure (Ps)-SV relationships of the ventricle and arterial system.
• Predicted SV from the intersection of these relationship lines.
• Modeled arterial impedance using a 3-element Windkessel and ventricular properties (Ees, V0, ejection time).
• Validated the framework by comparing predicted SVs with measured SVs in eight isolated canine ventricles under various preload and arterial impedance conditions.

Main Results:

• The analytical framework accurately predicted stroke volume (SV) in isolated canine ventricles.
• Predicted SVs showed a high correlation (P < 0.0001) with measured SVs (average r = 0.985).
• The model demonstrated high accuracy with a slope of 1.00 and a gamma-axis intercept of 1.0 ml.

Conclusions:

• The developed framework effectively represents the ventricle and arterial system using Ps-SV relationships.
• This approach provides valuable insights into how ventriculoarterial coupling determines stroke volume.
• The findings support the utility of this framework for understanding cardiac mechanics and SV regulation.