Key result
CPP below ~72-81 mmHg impairs myocardial contractility in experimental Fontan models.
Why the study?
The relationship between coronary perfusion pressure and myocardial contractility and the effects of acute right atrial pressure elevation in Fontan circulation were not well characterized.
Does acute elevation of right atrial pressure affect myocardial contractility at varying coronary perfusion pressures in a Fontan circulation model?
Does acute elevation of right atrial pressure affect myocardial contractility at varying coronary perfusion pressures in a Fontan circulation model?
In an experimental Fontan model, both coronary arterial and venous pressures affect myocardial contractility, with elevated right atrial pressure severely decreasing contractility at lower coronary perfusion pressures.
May inform coronary perfusion targets in Fontan physiology; hypothesis-generating and leaves open clinical translation.
We investigated the relationship between coronary perfusion pressure (CPP) and myocardial contractility and the effects of an acute elevation of right atrial pressure (RAP) on this relationship in an experimental model of Fontan circulation in 6 anesthetized open-chest dogs with isolated perfused coronary arteries. The relationship between CPP and Ees could be described by biphasic J-shaped curves which were nearly identical before and under Fontan circulation. While above a "critical" CPP (72 +/- 9 mmHg vs. 81 +/- 8 mmHg, n.s.) the changes of CPP did not affect Ees, below this level the decrease of CPP resulted in a progressive decrease of Ees. Under Fontan circulation, the progressive increase of RAP did not influence Ees at CPP = 100 mmHg, led to a moderate decrease of Ees at CPP = 75 mmHg and severe decrease at CPP = 60 mmHg. Thus, both coronary arterial and venous pressure affect myocardial contractility after Fontan procedure.
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Szabó et al. (2002) studied Fontan circulation (n=6). Acute elevation of right atrial pressure and changes in coronary perfusion pressure vs. Baseline / before Fontan circulation was evaluated on Relationship between coronary perfusion pressure (CPP) and myocardial contractility (Ees). In an experimental model of Fontan circulation, both coronary arterial and venous pressure affected myocardial contractility, with contractility decreasing below a critical CPP of 72-81 mmHg.
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