Heart Murmur and HCM in Cats: What You Should Know

I’m often asked by clients about heart murmurs, especially those looking to buy a Maine Coon kitten.

Many of them share heartbreaking stories — how their previous cat died from a heart condition, or how a routine checkup turned into panic.

It’s time to tell the truth — the kind you rarely hear from a vet.

💓 What is a murmur (heart murmur)?

It’s a sound a vet hears through a stethoscope when listening to the heart.

It’s not a disease. It’s a symptom. And it can appear in both healthy and sick animals.

There are two types:

• Physiological (temporary) — seen in scared, excited, or young animals.

• Pathological — caused by real heart conditions, like HCM.

😾 In 90% of healthy cats, the murmur is caused not by disease, but by stress from the vet visit itself:

• Travel in a carrier = stress

• Held down by a stranger

• Fur shaved, chest touched, cold gel applied for ultrasound

• Blood drawn from leg or neck

• The cat panics → heart rate and pressure spike → temporary murmur

👉 That murmur often disappears 10 minutes after the cat returns home.

But the client is already told:

"We hear a murmur — you must get an ultrasound immediately!"

Should you do an ultrasound "just in case"?

If your cat has no symptoms, and you're doing it "just to check":

⚠️ Be aware:

• Ultrasound is not a neutral procedure

• It uses high-frequency vibrations that slightly heat tissues

• Frequent use (especially during pregnancy) has documented risks

• For sensitive cats, it’s stressful and can trigger:

– panic attacks

– vomiting

– refusal to eat

– fear of the carrier

– long-term anxiety

🧨 One of my clients had a healthy cat who was traumatized by endless tests and injections. He now panics at the sight of a carrier. That’s not medicine — that’s damage.

🧬 What is HCM?

HCM (Hypertrophic Cardiomyopathy) is a serious heart condition where the heart walls thicken. But here’s what you need to know:

HCM is not a purely genetic disease — it’s multifactorial.

That means:

• 🧬 There may be a genetic predisposition

• But that alone does not cause the disease

• It needs external triggers to activate, such as:

– stress (especially vet-related)

– travel

– hormonal shifts (growth, mating)

– vaccines

– overheating

– poor diet

– toxins

💡 Even a “genetically clean” cat can develop HCM if constantly exposed to stress and medical interventions.

Let’s be honest:

A genetic predisposition only means some ancestor may have had the disease.

But here’s the part no one wants to say out loud:

It doesn’t matter whether the genetic test is clean or not — a cat is not guaranteed to be safe from HCM.

Because this condition is activated, in most cases, by stress.

Like many diseases, it often begins with trauma, chronic anxiety, overmedication, or poor diet.

🙅‍♀️ I have nothing against vets — everyone has their business, and people need to feed their families.

But modern veterinary medicine, especially in the U.S., has become:

FEAR = PROFIT

• The more fear → the more tests, ultrasounds, prescriptions, and prescription-only food

• And when nothing is found, they offer you a kind of “emotional band-aid”:

👉 “There’s a murmur… come back for checkups every 6 months.”

This is not treatment. It’s a business model.

Honest answers to common questions:

❓ Should I panic because of a murmur?

No, especially if it was found only once and your cat has no symptoms.

❓ Can an ultrasound show nothing, even with a murmur?

Yes, especially if the murmur was stress-induced.

❓ Is frequent ultrasound harmful?

Yes, especially for sensitive animals.

❓ Can vets exaggerate to sell food, meds, or tests?

Yes, especially in the U.S. Here’s why:

In America, most medications and vet diets are prescription-only.

In many other countries, you can just go to a pharmacy and buy what your cat needs.

That creates competition and accountability. In the U.S., monopoly and fear often rule.

❓ Can cats die from HCM?

Yes, but only in advanced cases. It’s not “sudden death in a kitten” the way it’s sometimes framed.

❓ Should the breeder be blamed for a murmur?

No.

Even if your vet says so — remember:

• 90% of murmurs are caused by stress

• Murmur is not a diagnosis

• Even a genetically clean cat can develop symptoms under pressure

• You don’t stick a cold stethoscope on a scared cat and call that science