Pressure tracings in constrictive pericarditis

Abnormal right atrial and ventricular pressure waveforms in a patient with constrictive pericarditis. Note the elevation and equalization of end-diastolic pressures, with a characteristic "dip and plateau" (or "square-root sign"). The steep Y descent reflects rapid early ventricular filling as right atrial emptying is rapid and unimpeded. The nadir of the Y descent reflects abrupt cessation of early diastolic ventricular filling. A similar pattern may be seen in cardiac tamponade or restrictive cardiomyopathy.