Ventricular systolic interdependence: volume elastance model in isolated canine hearts

Area of Science:

• Cardiovascular Physiology
• Biomedical Engineering
• Cardiac Mechanics

Background:

• Understanding ventricular interaction is crucial for cardiac function.
• Previous models often simplified the complex interplay between the right and left ventricles.
• The mechanical properties of the interventricular septum significantly influence overall cardiac performance.

Purpose of the Study:

• To develop and validate a three-compartment model analyzing right and left ventricular interaction.
• To quantify the elastance of individual ventricular compartments.
• To determine the directional differences in systolic cross-talk gain between the ventricles.

Main Methods:

• Developed a three-compartment elastic model (left ventricular free wall, septum, right ventricular free wall).
• Measured end-systolic volume elastance in isolated blood-perfused canine hearts.
• Assessed cross-talk gain (GRL and GLR) through direct pressure measurements and analysis of end-systolic pressure-volume relationships (ESPVR).

Main Results:

• The functional septum demonstrated significantly higher elastance compared to free walls in both directions.
• Right-to-left ventricular interaction (GRL) was consistently found to be approximately twice as large as left-to-right interaction (GLR).
• Model predictions for cross-talk gain were validated by direct measurements and ESPVR shifts.

Conclusions:

• Systolic cross-talk gain is significantly greater from the right ventricle to the left ventricle than vice versa.
• The three-compartment volume elastance model provides a powerful framework for interpreting ventricular cross-talk.
• Findings highlight the critical role of septal mechanics in inter-ventricular communication.