Cats and heart disease

I’m hoping to get some opinions from veterinarians, especially anyone with experience in feline cardiology or nutrition. I’m starting to wonder if I should be looking more closely at something my cats have in common.

I have four male cats, all of whom were originally feral/outdoor cats found around my parents’ country property. We looked for owners and cared for/socialized them with the intention of getting them adopted. They either never got adopted or weren’t really adoptable, so they ultimately became ours.

TC was completely wild/outdoors for approximately 4-6 years. Wally was outside for at least a couple of years and had been TNR’d. He was eventually adopted to a farm where he continued living outside. Long story, but he eventually came into my care and is now legally mine.

Now two of my cats have developed heart disease/heart failure.

TC was diagnosed with congestive heart failure Dec 2025 and is currently being treated for it.

More recently, Wally had an elevated proBNP, and X-rays showed an enlarged heart along with cloudiness/fluid in his chest/lung area. He has now also been diagnosed with heart failure and is currently on furosemide and pimobendan while we wait for his echocardiogram tomorrow.

Then last night Van, another one of my cats, had a coughing episode. I realize that coughing in cats does NOT automatically mean heart disease and can have many respiratory causes. But after having two cats develop heart disease, it made me stop and wonder if I’m missing some common factor.

This is where I’m especially curious about their diet and previous environment.

For approximately the first 5 years that we cared for them, they ate Taste of the Wild at my parents’ house.

My veterinarian later recommended switching them to Purina Pro Plan, so I did. I’ve changed flavors/types a few times over the years, but they have consistently been on Purina Pro Plan since then. They currently eat Purina Pro Plan LiveClear Weight Management.

I know there has been discussion about certain grain-free diets and diet-associated DCM, particularly in dogs. I also understand that cats are obligate carnivores and that a higher-protein diet itself isn’t necessarily a problem. I’m NOT assuming Taste of the Wild caused anything. I’m wondering whether their history of eating it for several years is something their cardiologist or a veterinary nutritionist would consider relevant now that two cats have heart disease.

I also occasionally give them cooked chicken, salmon/whitefish and sardines as toppers.

There is also another shared environmental factor:

The house they previously lived in had a significant black mold problem before the home was remodeled. TC lived in the house for 5 years, while Wally was living outside near the house while we were trying to tame him.

I don’t know what species of mold it was, and I have no way of knowing their actual exposure level. I’m absolutely NOT assuming mold caused their heart disease. But because these cats shared that environment for years, I’m wondering if chronic mold exposure could have any relationship to cardiac disease, respiratory disease, chronic inflammation, or anything else that would be relevant to mention to their vets.

For additional environmental context, I don't use scented plug-ins or air fresheners in my home, and I don't burn scented candles around the cats. I try to be pretty conscious of airborne irritants because of them.

Van coughing last night especially made me wonder about the respiratory side of this.

So these are really my main questions:

• When two cats from the same household/environment develop heart disease or CHF, do you start looking for a common factor, or is this not particularly unusual?

• Would their previous diet of Taste of the Wild for several years be relevant when investigating their heart disease?

• Are there nutritional deficiencies/excesses associated with feline cardiomyopathy other than the well-known taurine deficiency connection?

• Would there be any value in actually testing taurine levels or other nutritional markers?

• Is Purina Pro Plan LiveClear Weight Management considered an appropriate long-term food for cats with or potentially at risk for cardiac disease?

• Could years of living in and around a house with significant mold contamination have any known cardiac or respiratory consequences in cats?

• With Van having a new cough and two other cats in the household having heart disease, would you proactively screen Van? Would you start with an exam/chest X-rays/proBNP, or is an echocardiogram warranted based on the history?

I’m not looking to diagnose or treat my cats through Reddit, and I will not change their medications based on Reddit advice. They are under veterinary care. Wally is also waiting for his echocardiogram 9/22/26.

I’m mainly trying to figure out whether having two cats with heart disease is simply an unfortunate coincidence or whether there is something about their shared history, diet, or environment that I should be bringing to my vets’ attention.

After Wally got diagnosed, I think my brain basically went, “Okay…why are multiple cats in my house having issues? Is there something I’m missing?”

TC — roughly age 14? Probably weighs 8-10 lbs.

Wally — roughly 8, weight 14.25 lbs.

Van — 7, weight — he's my toddler lol. He has to be like 18 lbs. He's a tank and I try to keep him from eating other cats' food. Just doesn't always work.

(I even have a 4th cat Oliver-still fairly feral. Working with him quite a bit. He enjoys being part of the crew. Still working on touch)

Please don't be too hard on me about their weight. We switched to 1/3 cup in the morning and 1/3 cup at night per cat. They get a small spoonful of Friskies wet food with water added at dinner. The real fish, chicken or sardines are given in very small amounts occasionally, as I'm trying to transition them away from the wet food and healthier options.