Echo Case: When ECGs and Echos Collide

Ronald H. Wharton, MD


July 27, 2016

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Hello. This is Ronald Wharton. I am a cardiologist at Montefiore Medical Center and an assistant professor of medicine at the Albert Einstein College of Medicine. Thank you for tuning in. I titled this case study "When ECGs and Echos Collide," and as I go through it, you'll see why. This is a fun case. What I'm talking about today is probably my favorite topic in echocardiography, which is diastology.

As you all probably know, the American Society of Echocardiography published new guidelines for assessment of diastolic function and filling pressures in the April edition of the Journal of the American Society of Echocardiography.[1] I thought it was a very good revision because the previous guidelines (which were 7 years old) were far too cumbersome in my and many people's opinion.

If we look at the algorithm for discerning filling pressures in patients who have left ventricular dysfunction, there are only a few parameters one really has to look at. You should look at the E velocity, the A velocity, the left atrial volume, and the velocity of the tricuspid regurgitation jet, and perhaps also the ratio of E, mitral E, to the annular velocity e'.

The algorithm is much simpler than it used to be. So, simple enough to say, if you have an E velocity ≤ 0.5 m/s and an E/A ratio ≤ 0.8, you have normal filling pressures or grade I diastolic dysfunction.

If your E/A ratio is ≥ 2, then we know that you have severely elevated filling pressures, and that would be considered grade III diastolic dysfunction. And in the middle there are a few other things that you need to look at.

You need to look at the E/A ratio. You need to look at the mitral E to lateral or medial, or ideally an average of the two septal and lateral annular velocities. And you should look at the TR jet with an understanding that if the TR jet has a velocity > 2.8 m/s, you have pulmonary hypertension. And if you've got pulmonary hypertension with a bad left ventricle, the two are probably related, and you can probably say, therefore, that there are elevated filling pressures and that the patient has grade II diastolic dysfunction. The guidelines are a lot simpler than they used to be.

Here's the history. This is a patient who is short of breath, and a day before he had a radiofrequency ablation to treat chronic atrial fibrillation.

If you look at the images, here's the apical four-chamber view. The right ventricle size and the right atrium size look normal. The left ventricle is a little dilated and somewhat hypokinetic. It's not the worst left ventricle I've ever seen. It's not the best. I'm guessing the ejection fraction is about 30%. Left atrium is enlarged.

Given the history of chronic atrial fibrillation, an enlarged left atrium in and of itself isn't particularly surprising. How would we evaluate the diastolic function or the filling pressures in this patient?

Well, here's a pulse wave Doppler through the mitral valve, and you can see that the E-wave velocity is about 0.86 m/s. The stenographer's measuring an A-wave velocity. I'm not sure I really believe that, but we can talk about that. It's the little green dot that says 0.25 m/s. I think the stenographer's actually imagining it. The deceleration time of the mitral valve E-wave is 190 ms.

If you look at the lateral tissue Doppler velocity, the mitral lateral e' is 11.7 cm/s.

Let's look at the Doppler data here. The mitral E velocity is 85 cm/s. That's within normal limits. The lateral e' velocity is 11.7 cm/s. That's well above the threshold (which is, about 7 cm/s). The E/e' lateral ratio is 7.3. The guidelines say that as long as you're below 13 on the lateral annulus, the filling pressures should be normal. And then they measure an A velocity, as I had mentioned before. Is that A velocity real?

Let's look again. It's really hard to say that there's a definite A-wave in between the QRS complexes in diastole. If you look at the tissue Doppler velocity, I'm not sure that I see an a' velocity either. Just because the patient was cardioverted to sinus rhythm, it doesn't necessarily mean that we have restored atrial mechanical function to normal after only 1 day of sinus rhythm.

If you look at the next slide, there's a parasternal long axis on the same patient. Look at the mitral valve; you don't really see the two motions that you typically see when a patient is in sinus rhythm. You don't see E and A. You don't see the mitral wave opening, closing, and then the mitral valve opening again just before atrial systole. It's a regular rhythm, and I can guarantee you that the ECG on this patient definitely does demonstrate sinus activity. Sinus rhythm is restored, but the mitral valve motion doesn't really correlate with that.

If you look at the same thing again, here's the apical four-chamber view again—look at the mitral valve. It's not really moving twice in diastole, as you would expect in sinus rhythm. It's only moving once. So the ECG may say sinus, but the echo doesn't really say that atrial systole has been restored yet. The echo is functioning as if the patient is still in atrial fibrillation.

What do we do? We have a phenomenon of an electromechanical dissociation. Maybe we should approach this patient's echo regarding their filling pressures as if they have atrial fibrillation. Does that change anything?

Well, here are the guidelines for atrial fibrillation.[2] Isovolumic relaxation time (IVRT): < 65 ms. That wasn't measured on this echo. The deceleration of the pulmonary vein: D-wave < 220 ms. That's difficult to get in most patients, and they didn't get a good pulmonary vein Doppler in this patient either. E/e' on the septal side ≥ 11. I have a lateral. I don't have a septal.

An E-wave deceleration time of < 160 ms. This patient has a deceleration time of 190 ms. That's normal. So by atrial fibrillation guidelines, the filling pressures should be normal.

So, what do we do? The deceleration time is normal. I don't have a septal. I only have a lateral e', which is a little harder to adjudicate. From the data that I have, you would think that even if we apply the atrial fibrillation guidelines (especially the deceleration time > 160 ms), the filling pressures should be normal. Even though the patient is complaining of shortness of breath, we can say, "Relax. It's not your heart. You're not in heart failure because these guidelines say you're not in heart failure, probably." Right?

Well, just remember that when a patient has an atrial fibrillation ablation, they also have a temporary atrial septal defect (ASD) because the ablation requires that a transseptal atrial puncture be made to allow access to the left side of the heart from the right side of the heart.

And here we see the iatrogenic ASD in the subcostal view. It's that little red jet that's coming in intermittently. If you can see a jet on an echo, you can Doppler it.

Here's a continuous-wave Doppler through the ASD. You can see here that at peak, the gradient between the left and right atrium is 30 mm Hg.

What does that tell us? That tells us that even if the right atrial pressure is as low as it could be, the LA pressure must be high.

Take-home message? Guidelines don't always work, and to quote a very famous philosopher, "In theory, there is no difference between theory and practice. In practice, there is."

The famous philosopher, in case any of you are interested, is Yogi Berra. Anyway, just an example of how guidelines can fool you in certain situations. And just a reminder that sometimes you can take advantage of findings that are present in some patients, which can help you adjudicate or differentiate heart failure when the guidelines don't necessarily correlate with your clinical judgment.

Thank you for tuning in. This is Ronald Wharton from Montefiore Medical Center on at Medscape Cardiology. Glad you listened and hope you enjoyed it.

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