Pulsed-wave Doppler recordings for chronic obstructive pulmonary disease versus constrictive pericarditis

In patients with COPD, the pulsed-wave Doppler echocardiogram shows pronounced respiratory variation in SVC blood flow velocity (dashed double arrow, panel A), which is not seen in CP. In contrast, the mitral flow velocity (panel B) shows a similar respiratory variation (E wave, arrows) in COPD and CP. Recording SVC blood flow velocity is therefore a simple way to distinguish pulsus paradoxus due to CP from that due to COPD.