The pericardium and ventricular interaction, distensibility, and function

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Abstract
To examine the influence of the pericardium on distensibility, function and mechanical interaction of the left (LV) and right (RV) ventricles, 15 isolated canine hearts were studied with and without the pericardium. Over the end-diastolic pressure range 0-20 mm Hg the following relationships were assessed in each ventricle before and after pericardiectomy: RV and LV end-diastolic pressure (EDP)-volume (EDV) curves (distensibility); RV and LV peak developed isovolumetric pressure (DP)-EDV curves (systolic function); and the influence of varying the chamber size of 1 ventricle on the EDP (diastolic interaction) and DP (systolic interaction) of the other ventricle. For both ventricles pericardiectomy resulted in a significant decrease (P < 0.05) in EDP and in the degree of diastolic interaction at any given EDV over the 0-20 mm Hg range of filling pressures examined; the decline in EDP was dependent on the absolute level of EDV. Reductions in DP and in the degree of systolic interaction were noted following pericardiectomy; only the decrease in RVDP was significant (P < 0.05). The pericardium serves to influence the distensibility of each ventricle and enhances the mechanical interaction between ventricles during diastole. The systolic performance of the right ventricle is augmented by the presence of the pericardium but its influence on left ventricular function is more variable.