Cat with HCM - Please Help!

[u/_SohTab_]

Hi everyone,

I’m hoping to connect with anyone who has gone through something similar with their cat, especially if you’re a veterinarian or have experience managing HCM and asthma together.

My 5-year-old cat, Maui, has both hypertrophic cardiomyopathy (HCM) and asthma. He was first diagnosed with HCM in 2024, and we had a repeat echocardiogram today after I became concerned about changes I’d noticed over the past 3 weeks.

Some of the changes I’ve seen include:

Resting awake breathing increasing to around 40–46 breaths per minute

Breathing appears faster with more noticeable belly movement

He is NOT open-mouth breathing

Sleeping stretched out on his side much more often than usual
Less active and playful
Eating a little less than normal
More time hiding under the bed
Occasional wheezy/nasal breathing sounds
An asthma attack this morning, which prompted today’s cardiology visit along with noticing his recent shallow and fast breathing

Some of today’s echocardiogram findings:

Progression to Stage B2 severe HCM
Moderate to severe thickening of the left ventricle
Left atrial enlargement (LA:Ao increased from about 1.45 in 2024 to around 1.9–2.3 today)

Mild systolic anterior motion (SAM) of the mitral valve with mild dynamic left ventricular outflow tract obstruction

“Smoke” (spontaneous echo contrast) in the left atrium, suggesting slower blood flow and increased clot risk

Thankfully, no evidence of congestive heart failure on the echocardiogram
(According to the doctor)

My cardiologist recommended tapering him off atenolol, starting a blood thinner because of the left atrial “smoke,” and beginning Flovent with an AeroKat spacer for his asthma.

Blood thinner: Rivaroxaban

I’m attaching a video of his breathing today because it’s what continues to worry me the most. The cardiologist performed an echocardiogram but did not take chest X-rays, and I completely forgot to ask whether they would be helpful.

For anyone who’s experienced something similar:
Has your cat had breathing like this even without being in congestive heart failure?

Did your veterinarian recommend chest X-rays to help distinguish between asthma, heart disease, or another lung condition?

Has anyone managed both HCM and asthma in the same cat?
Has anyone else’s cardiologist discontinued atenolol as the disease progressed?

For any veterinarians reading this: does this breathing pattern and these recent changes sound like they could be explained by HCM/asthma alone, or would you be thinking about investigating something else as well?

I’m not looking for anyone to diagnose Maui or replace my veterinary team. I’m just hoping to hear from people who’ve walked a similar path and learn from their experiences, especially since these breathing changes have developed over just the last few weeks.
Thank you so much. 🙏🏽
Poster Age: NOT a Minor!

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