The pericardium exerts constraint on the right ventricle during cardiac surgery.

The right ventricle may be particularly susceptible to the effects of pericardial constraint. This study examined the effects of pericardiotomy on right ventricular function. Twenty-four anesthetized patients with coronary artery disease, but without evidence of pericardial pathology, were studied. Anesthesia consisted of fentanyl (100 micrograms.kg-1), diazepam, pancuronium, and 100% oxygen. The American Edwards REF-1 Cardiac Output Computer, rapid-response thermistor pulmonary arterial catheter, and a radial arterial catheter were used to measure hemodynamic variables. Baseline measurements were obtained with the sternum fully retracted. The measurements were then repeated following pericardiotomy by a midline incision. There were significant (P less than 0.05) changes in systolic arterial pressure (+4.5%), mean arterial pressure (+3.7%), systolic pulmonary arterial pressure (+11.8%), cardiac output (+9.1%), stroke volume (+6.9%), right ventricular end-diastolic volume (+7.6%), and right atrial pressure (-8.6%). In the current study, pericardiotomy augmented right ventricular diastolic filling and stroke volume, while the right atrial pressure decreased. These results support the concept of pericardial constraint.