What does coronary perfusion pressure (CPP) equal?

Coronary perfusion pressure (CPP) is an essential concept in understanding the blood flow to the myocardium (heart muscle) during cardiac arrest or after myocardial infarction. It is defined as the difference between aortic diastolic pressure and right atrial pressure. This specific relationship highlights the driving force for coronary blood flow during diastole, which is when the heart muscle is typically perfused.

Aortic diastolic pressure represents the pressure within the coronary arteries when the heart is in its resting phase (diastole), allowing the heart to fill with blood. The right atrial pressure, on the other hand, approximates the pressure that opposes coronary blood flow at the end of diastole. Therefore, when you subtract right atrial pressure from aortic diastolic pressure, you obtain the net pressure available to perfuse the coronary arteries.

This distinction underscores the importance of the diastolic phase and the relationship between systemic blood pressure and the heart's ability to receive adequate blood flow. It is critical in the context of resuscitation and the management of heart conditions, as maintaining an optimal CPP can significantly impact the outcomes of cardiac interventions.