Dynamic right ventricular dimension. Relation to chamber volume during the cardiac cycle

Area of Science:

• Cardiovascular Physiology
• Cardiac Mechanics
• Hemodynamics

Background:

• Right ventricular (RV) geometry and contraction complexity have historically limited performance analysis.
• Assessing RV function typically requires complex measurements of instantaneous dimensions and volume.

Purpose of the Study:

• To investigate the relationship between RV free wall dimension, pressure changes (dP/dt), and pulmonary artery flow.
• To establish a method for accurately assessing RV performance using dynamic dimensional changes.

Main Methods:

• Utilized sonomicrometry for RV free wall chord dimension, micromanometer catheters for RV pressure, and electromagnetic probes for pulmonary artery flow in open-chest dogs.
• Analyzed the temporal correlation between peak positive/negative RV dP/dt and the initiation/cessation of pulmonary flow.
• Quantified the relationship between RV stroke volume and dimensional changes, and RV stroke work and pressure-dimension integrals.

Main Results:

• Peak positive RV dP/dt closely preceded pulmonary flow initiation, with minimal dimensional difference.
• Peak negative RV dP/dt correlated with end-ejection, with minimal dimensional difference from minimal dimension.
• RV stroke volume directly correlated with dimensional change (r=0.969) and RV stroke work correlated with measured stroke work (r=0.980), independent of afterload changes.

Conclusions:

• Dynamic RV free wall dimension analysis provides accurate beat-to-beat assessments of RV chamber volume.
• This dimensional analysis method reliably estimates RV stroke work, unaffected by afterload variations.
• Simplifies RV performance evaluation, overcoming geometric complexities.