– 1 year old Sphinx cat with a bilateral loud murmur, no clinical signs.
– How would you classify this VSD? Perimembranous? Restrictive?
– There is 2 directional flow through the VSD, is this normal for a left to right shunt?
– My maximum velocity is just under 2m/s, is this due to incorrect allignment?
– Is there risk of progression to left sided overload?
I have not diagnosed many congenital defects and any help is much appreciated, thank you!
– 1 year old Sphinx cat with a bilateral loud murmur, no clinical signs.
– How would you classify this VSD? Perimembranous? Restrictive?
– There is 2 directional flow through the VSD, is this normal for a left to right shunt?
– My maximum velocity is just under 2m/s, is this due to incorrect allignment?
– Is there risk of progression to left sided overload?
I have not diagnosed many congenital defects and any help is much appreciated, thank you!
Comments
VSD is the most common cat
VSD is the most common cat congenital defect and this looks like a muscular vsd instead of a membranous vsd. The progression typically, when the defect is large enough, progresses to right sided overload and Eisenmenger’s physiology kicks in and then reveral of flow as right sided pressures equal left sided pressures and the right heart gets bigger and bigger. Exercise intollerance is usually what shows clinically (if not sudden death) and PHT eventually and right chf. But there are a number of things that can occur. Remember always with a VSD to rule out PS as well as you may sneak up on a Tetralogy by starting with the VSD and workign through the processiuon hence why our SDEP echo protocol was created to cover the congential defects as well as they all fall withn the view progression. Last I heard there wasn’t any sx tx on this but Peter is the guy playing with scalpels and hearts so let me see if i can bring him in on this.
These cats can go on for a long time though so ya never know when sudden death happens or they plug along for years. They are cats and really have 9 lives just this one may burn through them faster than his buddies.
Curbside guide has a complete writeup on all congenital defects and latest and greatest info that may help if you have it:
https://sonopath.com/products/book
Thanks Eric, I have both the
Thanks Eric, I have both the curbside guide and the SDEP echo protocol, both very helpful!
Do you think this would lead to right sided heart failure rather than left volume overload because it is muscular?
Great glad you like sdep
Great glad you like sdep products! Well the net flow and pressure will push the volume to the right until Eisenmenger comes to town and reversal occurs to push it back left. Where he fails right or left depends if he lives long enough to reach reversal of flow and left failure as well and phisiological explanations that are beyond my pay grade which is why the world has McGyver guys like Peter that can build an airplaine from rubber tubing and some gigli wire:). Again tough to say where this cat ends up. Peter may chime in with more insight.
Thanks Eric. Any comments on
Thanks Eric. Any comments on my questions Peter?
Hi!
This case might be a bit
Hi!
This case might be a bit more difficult, although I completely agree with Eric.
What I see is some concentric hypertrophy, but no volume overload, neither right or left. The left ventricular wall and the septum appear a bit thickend – as far as I can see. Muscular septum defects are more rare than peri-membranous ones. In my experience, they are often associated with pulmonic stenosis, as Eric wrote. In your case I would doubt a bit if this “hole” is really a VSD because it is large and does not really lead through the entire ventricular septum. If it was a VSD, I woudl expect much more left ventricular volume overload, because it is large. The gap could also be caused by an abnormal papillary muscule.
Regarding pressure gradients: If there is bi-directional flow, both ventricles should look similar in terms of wall thickness and diameters because the pressures have to be equal. The bi-directional flow would then be a consequence of the timing of ventricular contraction. On the apical view, the right ventricular wall seems to be quite normal. If the VSD is so small (restrictive) that it does not cause right or left ventricualr changes, then the pressure gradient shoudl be around 100-120 mm Hg, because the defect would be “restrictive” (keeping normal PGs upright).
Re doppler adjustment: The color Doppler Nyquist limit is low, this means, there is a lot of color bleeding superimposing the greyscale image. When examining the ventricular septum, I woudl set it at at least 0.8 m/s, if not higher.
Regarding the heart murmur: in a VSD I would expect a right sided loud heart murmur. If there is an Eisenmenger-reaction,the heart murmur would decrease in intensity till it is not audibe anymore. If there is a VSD and pulmonic stenosis, there would be indeed a right and a left sided heart murmur. But this would have to be excluded by Doppler across the RVOT. Given the appearance of the right ventricle, I do not expect a severe pulmonic stenosis, though.
Re disease progression in a VSD: I agree with Eric. If hemodynamically significant, a VSD causes left sided CHF or an Eisenmenger-Reaction caused by pulmonic overcirculation. Sometimes, initially small VSDs in cats can cause hemodynamic changes later on, this is, why these patients need to be monitored.
Re surgical treatment of VSDs: This is really difficult because in membranous VSDs the Bundle of HIS runs exactly at the border of the VSD downwards into the ventricle. Muscular defects are difficult to find from the right side and difficult to close. Valve repairs are easier to perform 🙂 I would close a VSD only if there is no other choice.
My recommendations for this case:
Get exact short axis views and look for septum defects on both sides of the ventricular septum. Get an exact SAX view of the heart base – this is better to confirm and Doppler a membranous septum defect because Doppler on 5-chamber views can sometimes mimic a VSD, particular if there is right and left sided dynamic outflow obstruction. Increasing the PRF helps.
Hope I have not caused more confusion than help.
Peter
Thanks Peter I knew you would
Thanks Peter I knew you would be able to dissect this more eloquently than I lol:)
Appreciated thanks
That is brilliant, really
That is brilliant, really informative thank you!
I have a RVOT view and could not see a pulmonic stenosis. I will keep monitoring this cat and post updates.