Pattern of right ventricular pressure fall and its modulation by afterload

Area of Science:

• Cardiovascular Physiology
• Cardiac Mechanics
• Hemodynamics

Background:

• The pressure decay patterns of the right ventricle (RV) and left ventricle (LV) differ significantly.
• Understanding RV pressure dynamics is crucial for diagnosing and managing RV-related pathologies.

Purpose of the Study:

• To investigate the pattern of right ventricular pressure (RVP) fall.
• To determine the afterload dependence of RVP decay characteristics.

Main Methods:

• Analysis of ventricular pressure curves and dP/dt phase planes in rat hearts in situ.
• Measurement of dP/dt(min) and time constant tau at baseline and during elevated RV afterload.
• Induction of variable RV afterload via pulmonary trunk constriction.

Main Results:

• RV pressure fall exhibits distinct accelerative and decelerative phases, differing from the predominantly decelerative LV pressure fall.
• Increased RV afterload led to higher RV dP/dt(min) and RV time constant tau.
• Elevated RV afterload shifted the RVP fall pattern towards a more decelerative course, resembling LV pressure decay.

Conclusions:

• RVP and LVP decline patterns are fundamentally distinct, with the RV exhibiting a more accelerative decay.
• RV pressure fall dynamics, including dP/dt(min) and tau, are significantly influenced by RV afterload.
• The time constant tau reflects a shorter segment of RVP fall compared to LVP fall, highlighting afterload dependency.