As with the mitral valve, there are no specific signs of tricuspid
regurgitation on echocardiographic recordings. With the widespread
use of Doppler echocardiography it has been learned that small
degrees of tricuspid regurgitation are quite common, being present
in over 65% of otherwise normal individuals. Such patients have
little, or no, evidence of murmur by auscultation.
When tricuspid insufficiency is severe, changes are noted echocardiographically.
In the majority of these cases, most functional tricuspid regurgitation
is secondary to pulmonary hypertension. Other causes include infective
endocarditis and/or abnormalities of the valve itself, such as
Ebstein's anomaly.
 |
| Fig. 37 |
The primary echocardiographic manifestation of tricuspid regurgitation
is volume overload of the right ventricle. The right ventricle
becomes enlarged, and the direction of the interventricular septal
motion appears to become reversed or "paradoxical". In fact, the
left ventricle contracts normally, but superimposed on its motion
is the greater movement of the hyperdynamic right ventricle
(Fig.
37).
 |
| Fig. 38 |
Contrast echocardiography has been shown to help in the detection
of tricuspid regurgitation if Doppler echocardiography is not
available. When a bolus of liquid, usually sterile saline, is
injected rapidly into a peripheral vein, microbubbles of gas are
released. On a two-dimensional display, echoes from these microbubbles
can be seen to pass back and forth across the tricuspid valve
and also seen passing retrograde into the enlarged hepatic veins;
they often continue for several minutes before they are eventually
cleared into the pulmonary artery. M-mode recordings show that
the contrast echoes first appear in the inferior vena cava during
systole, and can be seen passing retrograde into the enlarged
hepatic veins (Fig.
38).
2004
