Single Frame Echo Quiz

Transcript of the video: Interpreting an echo quiz just from a single frame has a lot of limitations. But, still for an academic exercise, we will try. Unlike the ECG, where a single image may be more informative, echo usually requires moving images. And moreover, even ECG requires a knowledge of the clinical background before interpretation, to avoid errors. Similarly, for echocardiogram, what we would do usually is, first we do a clinical history evaluation, then physical examination, and after that only we proceed with echocardiography in our routine work. But for an academic curiosity, we will just try to interpret an echo image, which is a single frame only.

This is an echocardiographic image from the parasternal long axis view. This is the location of the transducer, and this is the sector scan. You can see the two dimensional sector imaging from an echocardiogram and I have marked out the aorta. This is the aortic valve in closed position and mitral valve also appears to be closed in position. That is because timing of the image may be in such a way that, it could have been in such a way that both valves are in closed position. And this is aorta and this is left atrium. From the images you do not know whether the mitral valve is really fully closed or almost about to be closed. These are the features which are evident from this still image. So I will give you a few moments, to think about the possible findings over here and arrive at a possible diagnosis or differential diagnosis.

I am sure that most of you are familiar with echocardiography would have come at the diagnosis and differential diagnosis by this time because it is a very simple view. And this is a better annotated view and I am showing the ventricular septal defect here. Right ventricle, left ventricle. You can also see the aortic override. The VSD is partly overrided by the aorta. So, when there is an aortic override, if the override of the aorta is less than 50%, you think of tetralogy of Fallot. And if it is more than 50% towards the right side, then you think of another condition known as double outlet right ventricle, where both great vessels, aorta and pulmonary artery arises from the right ventricle. And, another, still another condition which could have similar view is truncus arteriosus, where there is only a single great vessel. I have labelled this as aorta, but from this view alone, you cannot be hundred percent sure whether this is truncus or an aorta. You require multiple views to see from where the pulmonary arteries are arising. Another finding here, which is not very clear, is that there is a suspicion of a conus here. Separation between the attachments of the aortic and mitral valve. This could be a conus tissue. But again this is not obvious from this view because you should actually see the valves moving, aortic and mitral valves. Then only you will know whether there is great separation from the hinge point. The shadows are here, you could also see some shadows in the left atrium. So this need not be a true conus, it could be just an artifact also, because you are seeing shadows within the left atrium also. And, if this is indeed a conus, that will be a point in favour of double outlet right ventricle, than tetralogy of Fallot because, conus is usually seen below the pulmonary valve, and if bilateral conus are seen, it is a feature of double outlet right ventricle. Yet the override is not sufficient to say that this is double outlet right ventricle. Again, as I mentioned, all features should be assessed on moving film (error), moving videos and not just as still frame. Here there is also a suggestion of hypertrophy of free wall of right ventricle, which can occur in tetralogy of Fallot. So these are the differential diagnosis when you see an aortic override with a ventricular septal defect from the parasternal long axis view. Most common is tetralogy of Fallot, second is double outlet right ventricle, and still rare is truncus arteriosus. Clinical history may help in a way that, if it is an adult, the chance of it being a truncus is much lower, unlike in an infant.     So you would like to know whether this an echo frame from an adult or an infant. And all the three are cyanotic congenital heart diseases.