Hi Melissa!
Basically,
Hi Melissa!
Basically, isoflurane causes mainly a decrease in BP. This would lead to decreased afterload +/- preload.
If mainly the preload is decreased this could cause a depressed FS. Since your diastolic measurements are normal, there is no evidence of decreased preload.
If afterload is decreased and preload is normal, I would expect a higher FS, which is not the case here.
A normal preload and increased afterload can explain a depressed FS, but this is not explainable by isoflurane-anesthesia, but it could be explained by systemic hypertension.
So, I´m not totally convinced that the heart is normal. Still, if the left atrium is ok, and if there is no RV/RA enlargment seen, I would not expect significant hemodynamic compromise due to heart disease. What I would do is:
Measure the blood pressure
Use butorphanol (0.1-0.2 mg/kg) and Acepromacine (less than one drop, 0.005 mg/kg) for sedation.
Record an ECG: A heart rate of >240/min can be pathologic (doen´t have to be “only” sinus tachycardia)
Post videos on the forum.
Weird case you have…
Thx for posting!
Best Regards from Austria!

Peter

Thanks Peter. I am not the
Thanks Peter. I am not the primary clinician on the case. The original plan was to sedate with butorphanol ace, but the cat was so fractious they opted to gas him down in his carrier instead. CBC, chem profile and T4 were normal. They want to peform a dental on him, but wanted to evaluate his heart first. Perhaps my measurements are off, but just subjectively looking at the videos, the fractional shortening seems slightly depressed. I will try to post a video.

I have now added video clips
I have now added video clips from the right parasternal views to the original post.

Melissa, I dont have a study
Melissa, I dont have a study but eyeballing my experience I usually allow a drop of 5-10% on the fs% owing to anesthesia and this changes breed to breed…i.e. an athletic lab which would have a normal fs% of 35 or so and it drops to 25 ad normal chamber volumes that’s normal to me. If you ever echo a hypothyroid dog they kinda do the same thing and will stay in the high 20 to low 30% instead of a bouncing 35-45%. This would be a great study Peter….no? or has this been done already. As Peter said the chamber sizes particularly the LA is the key here as to clinical significance. Could have got the dental done when you knocked him down for the echo:) In healthy animals often i will coordinate the echo with the clinician and let them know if it looks good under sedation then they can go ahead with the dental hence sedating just once. Mobile clients and pet owners love that.

I agree. I did not know they
I agree. I did not know they were planning a dental until the day after….I think that they thought they were going to see a blatant cardiomyopathy. They also did a blood draw at the same time to look for crf, hyperthyroidism, etc. I’ll send you the images shortly and you can give me your professional opinion. I did get some minor increased meas. on the LVPWd on the transverse views, but I wrote this off as an angle issue since the left free wall measured normal on the long axis views.

Just doing a quick scan on the internet, I found a few abstracts on isoflurane in mice (no significant changes in FS), dogs (sl decreased FS), and human infants (no significant changes in FS). Doing a quick search I did not find anything on cats. As Peter stated above, there are lots of variables at play. I don’t know how they can get an accurate BP check on this cat unless they train the owners to do it at home.

Looking at the videos
Looking at the videos (beautiful ones!) I can only repeat what I have already posted. There is no sign of hemodynamic compromise at the moment but I would still reecho this patient since I´m not totally convinced if that´s really only the anesthesia that causes reduction is systolic function. FS is usually more constant in cats than it is in dogs…
Sorry for the late response….
Peter

Thanks Peter!
Thanks Peter!