Changes in the venous pulse waveform in pericardial effusion revealed by Doppler echocardiography of the superior vena cava

Abstract

Echocardiography is valuable for urgent assessment of the haemodynamic significance of pericardial effusions and thus assisting in the clinical diagnosis of cardiac tamponade. Classical echocardiographic findings (e.g. respiratory variation in trans-valvular velocities) are not always present and, when seen, may be attributable to other conditions (e.g. obesity or obstructive airways disease) (1). Therefore, it is important to be familiar with other abnormalities that may be observed, such as that in the superior vena cava (SVC). SVC imaging is best performed from the right supraclavicular window, with the transducer placed vertically in the fossa between the sternal and clavicular heads of the sternomastoid muscle and with the patient lying supine and the transducer marker pointing superiorly (2). Figure 1 (and Videos 1 and 2), taken in a 46-year-old male who presented with dizziness and had a large global pericardial effusion on 2D echocardiography, illustrate the changes seen in the SVC flow profile (which reflect the changes seen in the jugular venous pulse (JVP) waveform upon physical examination) before and after pericardiocentesis. SVC Doppler interrogation may be particularly valuable for determining the dominant haemodynamic condition in patients with both pericardial effusion and suspected pericardial constriction. In cardiac tamponade, compression occurs throughout the cardiac cycle and thus ventricular filling is impaired throughout diastole, resulting in minimal or no flow into the right atrium from the SVC during diastole (i.e. absence of the diastolic wave (absent Y descent in the JVP)) (3). However, in pericardial constriction, early ventricular filling is preserved and is rapid but ends abruptly as soon as maximum intrapericardial pressure is reached, resulting in both systolic and diastolic (D) waves though the D wave has a steep deceleration slope (Fig. 2), mirroring the rapid Y descent observed in the JVP (4).