Why is This TR Jet Different From Other TR Jets?

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Ronald H Wharton, MD: Hello, and greetings from the Bronx, New York. This is Dr Ronald Wharton. I am an associate professor of Medicine at the Albert Einstein College of Medicine and an attending cardiologist at Montefiore Medical Center. And for April, I would like to share with you a case which I have titled, "Why is this TR jet different from all other TR jets?"—TR specifically referring to tricuspid regurgitation.

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Those of you who are familiar with echocardiography will see that this is a continuous-wave Doppler signal obtained in the apical four-chamber view through the tricuspid valve. Take a look at it. And I now pose the question, what are we seeing here?

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Well, if you look closely, you will see that it is, in fact, all of the above. And I'm willing to venture that most echocardiographers don't come across a tricuspid regurgitation signal that looks like this quite so often. I figured it might be fun to dissect this and see what's going on. What's the reason that the tricuspid regurgitation signal looks the way it does?

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Well, first, here's an M mode of the patient in the parasternal long axis through the mitral valve. You will notice that there look like there are E waves and A waves, but they aren't necessarily coming in standard intervals in standard places.

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In the next slide, you can see a parasternal short axis window through the tricuspid valve, demonstrating the tricuspid regurgitation jet.

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If I freeze the frame in diastole, you'll notice that the cursor on the electrocardiogram underneath the echocardiogram is in diastole, you can see that there is a nonturbulent jet going away from the tricuspid valve into the right atrium, demonstrating diastolic tricuspid regurgitation.

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So here's a clue as to what's going on. This is an apical four-chamber view. And you can see the lateral wall is thickening well. The septum seems to be somewhat hypokinetic. Parts of it are akinetic. The right ventricle is very dilated and very hypokinetic. And if you look very carefully, you can see a very bright signal toward the right ventricular apex.

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Focusing on the tricuspid valve with color Doppler, you can see that there are color signals of tricuspid regurgitation present both in systole, during which the TR jet looks more turbulent, and you see more of a mosaic of colors, and in diastole, when the signal looks more like a very soft blue, which represents a lower velocity.

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This is now a two-chamber view. And if you look at that, you can see that the anterior wall is thickening normally and the inferior wall is akinetic.

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In the next slide, you can see that there is a pulsed-wave Doppler with the sample volume placed in the left ventricular outflow tract in the five-chamber view. And you'll notice that despite the fact that the RR intervals are regular, the envelopes are varying in size, some of which are as low as 80 cm/s. Some get down to about 100 cm/s.

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So let's put this all together. Part of the septum is akinetic. The inferior wall is akinetic. The right ventricle is severely hypokinetic. There is a bright echo signal near the right ventricular (RV) apex. And you have tricuspid regurgitation in both systole and diastole. And even though the RR intervals are regular, the stroke volume, as demonstrated through the pulsed-wave signal in the left ventricular outflow tract (LVOT), is varying from beat to beat.

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This is what happened. This is a gentleman who came in with an acute inferior wall myocardial infarction. And his stenosis was sufficiently proximal in the right coronary artery to affect both the RV as well as the conduction through the atrioventricular (AV) node. His RV systolic function is poor. However, his right atrial systolic function remains unaffected.

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In addition, because the AV node has become ischemic, he has complete heart block. And the bright echo density in the echocardiogram is that of a temporary pacemaker.

So what's happened here? He has long PR intervals frequently because he's in complete heart block, which allow for diastolic tricuspid regurgitation. That happens because the TR is being driven by right atrial relaxation in the absence of concomitant right ventricular systole. So that's a very low-velocity TR jet, because that's being driven by right atrial (RA) diastole. However, the systolic TR jet is low velocity because of the mechanical dysfunction of the right ventricle.

Sometimes, RA systole is occurring at the same time as RV systole because of the complete heart block. When that happens, the RA pressure increases, thereby decreasing the gradient from the right ventricle to the right atrium and giving that notch, if you will, in the TR signal. I like to think of that as causing an A dip, or an atrial dip, in the TR jet.

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So, if you look at the next slide, this is the Doppler signal that I started this case with. You can see the systolic TR signals all have little notches in different places, which I call the "A dip," corresponding to those periods where RV systole and RA systole are happening at the same time. In addition, there are periods where RA diastole is occurring without simultaneous RV systole, causing diastolic tricuspid regurgitation as the right atrial pressure falls because of its own diastole.

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So, to wrap it up, this is one echocardiogram that demonstrates an acute inferior-wall MI with both a mechanical complication, the right ventricular involvement, and the electrical complication of complete heart block at the same time. I thought this was a sufficiently unusual and interesting echocardiogram that it was worth sharing with the echo audience out there. Thank you for listening. This is Ronald Wharton from Montefiore Medical Center in the Bronx, New York, on theheart.org on Medscape.