What does equal end diastolic pressures between both atria and ventricles suggest during cardiac catheterization?

Equal end-diastolic pressures between both atria and ventricles during cardiac catheterization strongly suggest constrictive pericarditis. This condition occurs when the pericardium, which is the fibrous sac surrounding the heart, becomes thickened and rigid, restricting the heart's ability to fill properly during diastole. When this happens, the pressures in the heart chambers equalize because the filling constraints affect both the atria and ventricles similarly.

In the setting of constrictive pericarditis, the heart's diastolic function is impaired, leading to elevated pressures in both the atria and ventricles. This phenomenon often manifests as a classic "square root sign" on pressure tracings, indicating that there is little difference in the pressures across the chambers.

Understanding this pressure relationship is crucial for diagnosing constrictive pericarditis, as it has specific therapeutic implications compared to other conditions like heart failure, cardiac tamponade, or aortic regurgitation, which exhibit different hemodynamic patterns.