Role of pericardial constraint for right ventricular function in humans

Area of Science:

• Cardiology
• Physiology
• Cardiac Surgery

Background:

• The pericardium, a sac surrounding the heart, can influence cardiac function.
• Understanding the pericardium's role in right ventricular (RV) function is crucial, especially under varying physiological conditions.

Purpose of the Study:

• To investigate the extent to which the pericardium constrains right ventricular function in human subjects.
• To determine if pericardial constraint on RV function is altered by changes in RV afterload and preload.

Main Methods:

• Twenty patients undergoing coronary artery bypass surgery were studied.
• Right ventricular volumes and pressures were measured using a Swan-Ganz thermodilution catheter before and after pericardiotomy.
• Measurements were taken at baseline and during elevated RV systolic pressure induced by pulmonary artery compression.

Main Results:

• Pericardiotomy alone did not significantly alter RV end-diastolic volume, ejection fraction, or right atrial pressure.
• Increasing RV afterload significantly raised right atrial pressure and reduced RV ejection fraction before pericardiotomy.
• After pericardiotomy, increased RV afterload led to increased RV end-diastolic volume and reduced RV ejection fraction, with no significant change in right atrial pressure.

Conclusions:

• The pericardium does not impose significant functional constraints on the right ventricle during normal diastolic filling.
• Under conditions of increased right ventricular preload, pericardial constraint plays a significant role in modulating right ventricular function in humans.