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The role of the pericardium in interactions between the cardiac chambers
Insights
Distending the right side of the heart affects left heart filling when the pericardium is intact. This influence on cardiac pressure-volume relationships disappears when pericardial pressure is accounted for.
Area of Science:
- Cardiovascular Physiology
- Cardiac Mechanics
Background:
- The pericardium influences cardiac filling and function.
- Atrioventricular distension impacts pericardial volume more than isolated ventricular distension.
Purpose of the Study:
- To investigate the effect of right heart distension on left heart pressure-volume relationships in intact pericardium models.
- To determine if pericardial pressure mediates the observed effects.
Main Methods:
- Utilized six postmortem canine hearts with intact pericardium.
- Measured left heart pressure-volume relationships with an empty and distended right heart (saline infusion).
- Analyzed pressure-volume curves with and without accounting for pericardial pressure.
Main Results:
- Increased right heart volume steepened the left heart pressure-volume curve.
- This effect on left heart filling characteristics was significant with an intact pericardium.
- The steepening of the left heart pressure-volume curve became negligible after subtracting pericardial pressure.
Conclusions:
- Right heart distension significantly affects left heart filling dynamics under intact pericardial conditions.
- Pericardial pressure is the primary mediator of this interaction.
- Excluding atria from right heart distension studies may yield different results due to higher compliance.
Abstract:
Distension of one side of the heart involves both the atrium and the ventricle, and such atrioventricular enlargement encroaches more on pericardial volume than would ventricular distension alone. The influence of distension of the entire right side of the heart on the pressure-volume relationship of the entire left heart was studied in six postmortem canine hearts with intact pericardium. The pressure-volume relation of the left heart was determined when the right heart was empty and when it was filled with saline. The pressure-volume curve of the left heart became steeper when the volume of the right heart was increased. However, after subtracting pericardial pressure from the left heart pressure, the pressure-volume curves were unaffected by increased volume of the right heart. Selective distension of the entire right heart has a considerable effect on the filling characteristics of the left heart when the pericardium is intact, although this is less than that observed in experiments in which the more compliant atria have been excluded. This effect becomes negligible after subtracting pericardial pressure.