Pericardial effects of diastolic ventricular interaction during development

Area of Science:

• Cardiovascular Physiology
• Developmental Biology
• Cardiac Mechanics

Background:

• Ventricular interaction, the influence of one ventricle on the other's function, is crucial for cardiac output.
• The pericardium's role in modulating ventricular interaction, especially during early development, remains incompletely understood.

Purpose of the Study:

• To investigate the impact of the pericardium on myocardial diastolic ventricular interaction in preterm and newborn lambs.
• To quantify the changes in ventricular interaction with and without the pericardium in vitro.

Main Methods:

• Hearts from preterm and newborn lambs were excised with the pericardium intact.
• Balloon catheters were used to measure left and right ventricular pressures and volumes.
• Pressure and volume transfer functions were calculated before and after pericardium removal to assess ventricular interaction.

Main Results:

• The pericardium significantly increased both pressure and volume transfer functions in both preterm and newborn lambs.
• The relative percentage increase in ventricular interaction due to the pericardium was similar between preterm and newborn groups.
• This suggests the effect is not age-dependent.

Conclusions:

• The pericardium plays a significant role in enhancing diastolic ventricular interaction in developing lambs.
• The findings suggest that the relative compliances of the ventricular walls and pericardium mediate this interaction.
• The pericardium's influence on ventricular interaction is established early in development and remains consistent.