Table 1

Comparison of certain features in subacute (elastic) and chronic (rigid shell) constrictive pericarditis

Subacute (elastic) Chronic (rigid shell)
Paradoxical pulse usually present, other signs of interdependence usually prominentParadoxical pulse usually minimal or absent, other signs of interdependence less prominent
Usually an XY waveform (“M” or “W” waveform)Y is predominant, X sometimes minimal
Dip–plateau pattern less conspicuous, because early diastolic nadir may not approach zeroDip–plateau usually conspicuous, because early diastolic nadir often reaches zero
Calcification usually absentCalcification often present
Pericardial effusion sometimes present, generalised or loculated. Constriction is by the visceral pericardiumPericardial effusion absent. The two layers of pericardium are fused, and jointly constrict the heart
P waves usually normalP waves often wide, notched and low in amplitude
Atrial fibrillation or flutter rareAtrial fibrillation or flutter common