Hearts That Murmur Their Own Tune: When Cats Have Irregular Sounds

Lucy
Sep 4
3 min read

Updated: Sep 15

Here’s the scoop:

Our trio of cats and their suspiciously swishy heart sounds
What feline heart murmurs actually are and when to worry (or not)
How stress, and peace of mind, can both play a role

When “Just a Checkup” Becomes Something Else

It started innocently enough. Many years ago, we did a routine wellness check for Daphne. We weren’t expecting anything major, just a quick in-and-out appointment. Then the vet tilted her head, listened a little longer with the stethoscope and said, “Huh. I’m hearing a heart murmur.”

Okay. Unexpected, but maybe not a big deal. We’d just keep an eye on it.

Then came Butabi’s visit. Same vet. Same surprise. “Hmm, another murmur here too.”

And then, because...of course, Ziggy had his appointment and yep. You guessed it. “A heart murmur as well.”

At this point, I was starting to wonder if the stethoscope had a loose wire or if we were just living in some kind of feline cardiac Twilight Zone. What are the odds that all three of our cats had heart arrhythmias? (this was before we adopted Lars and Zigrit…and to this day, no heart issues for them! Woohoo!)

A Field Trip to the Feline Cardiologist

Our vet, erring on the side of caution (and sanity), recommended we see a specialist across town. So off we went, herding cats...literally...on a long, grumbly drive that nobody in our car enjoyed.

Just to make things extra fun, we weren’t allowed to give them anything like gabapentin to take the edge off. Apparently sedatives can interfere with heart tests. So, no calming meds, just three yowling, deeply offended cats and two humans trying to act like this was fine.

Each cat got a full cardiac ultrasound (echocardiogram), and the verdict?

They all had heart murmurs.

What Is a Heart Murmur in Cats?

A heart murmur is an unusual whooshing or swishing sound heard during a heartbeat. It’s not an irregular rhythm (though they can coexist)...instead, it’s about the blood flow itself being turbulent rather than smooth.

Common Causes in Cats:

Innocent or physiologic murmurs (often seen in young or stressed cats)
Structural heart conditions (like cardiomyopathy)
Anemia or hyperthyroidism
Fever or infections
Stress or dehydration

Severity Levels:

Grade I-II (soft murmurs): Often benign or stress-induced
Grade III-IV: More noticeable and may warrant deeper testing
Grade V-VI: Louder murmurs that may signal structural heart disease

Symptoms? Maybe...or Maybe Not:

Many cats show zero symptoms, especially with mild murmurs
If there are signs, you might see lethargy, labored breathing or hiding
Some murmurs never progress and don’t require treatment

In our case, all three cats had mild, stress-related murmurs...not linked to disease, not symptomatic and not in need of medication. Just a note in their chart and a reason to keep monitoring over time.

Stress, It Turns Out, Can Be a Real Jerk

And wouldn’t you know it? They suspected stress may have been a big factor. The vet said, “It’s possible the murmur was exacerbated or even triggered by the anxiety of travel and the clinic environment.”

Well, if you’ve ever tried to wrangle three cats into carriers, drive them across the city and keep your cool while they yowl like you’ve ruined their lives forever...yeah. Stress checks out.

A Decade Later and No Noteworthy Heart Issues

That was nearly ten years ago and every new vet we’ve seen since has heard that same murmur during exams that ends up in a serious look. It always triggers concern at first, until I say those magic words...“We had it checked by a cardiologist. It’s benign.”

And just like that, the alarm settles. And so do I.

Because as a pet parent, few things bring more comfort than knowing you did the thing. You followed through. You got the answers. Even if the problem isn’t fixable, the knowing is power. And in our case, the knowing meant we didn’t have to worry.

Takeaway Treats:

Murmurs aren’t always bad news...sometimes they’re just the sound of a healthy cat under stress
Specialist visits may not be fun, but they offer peace of mind you can hold onto for years
Mild heart murmurs can stay stable for life...no meds, just monitoring
Always trust your instincts, even if it means herding three howling cats into the car!