Right ventricular dynamics during left ventricular assistance in closed-chest dogs

Area of Science:

• Cardiovascular Physiology
• Medical Devices
• Biomedical Engineering

Background:

• Left ventricular assist devices (LVADs) are crucial for end-stage heart failure.
• Understanding LVAD effects on right ventricular (RV) function is vital for patient outcomes.
• RV dysfunction can complicate LVAD therapy.

Purpose of the Study:

• To investigate the impact of LVAD support on global RV systolic mechanics.
• To assess changes in RV contractility, efficiency, and geometry during LVAD support.
• To elucidate the compensatory mechanisms maintaining RV function under LVAD conditions.

Main Methods:

• Utilized a closed-chest canine model with LVAD implantation.
• Implanted 27 tantalum markers for biventricular volume and geometry computation.
• Recorded hemodynamic parameters and biplane cinefluoroscopic images during vena caval occlusion.
• Assessed RV contractility (end-systolic elastance, preload recruitable stroke work) and myocardial efficiency.

Main Results:

• LVAD support increased RV end-diastolic volume and caused a significant leftward septal shift.
• Pulmonary artery input impedance decreased, indicating reduced RV afterload.
• Global RV end-systolic elastance and preload recruitable stroke work decreased, signifying impaired contractility.
• RV power output and myocardial efficiency remained unchanged.

Conclusions:

• LVAD support impairs global RV contractility and induces septal shifting.
• RV myocardial efficiency and power output are preserved through decreased RV afterload and increased RV preload.
• These findings highlight the complex interplay between LVADs and RV function.