The vet stopped talking for about two seconds longer than felt right, slid the stethoscope over an inch, listened again, and said the word "murmur."
You caught maybe half of what came after. Something about grades. Something about watching his breathing. A printout with three words circled in blue pen: resting respiratory rate.
You nodded like it landed. It hadn't, not yet.
Now it's hours later, the house has gone quiet, and he's asleep on his side with one paw twitching through a dream. You're sitting on the floor next to him, watching his ribs lift and drop, trying to decide whether what you're seeing counts as fine.
Maybe the vet caught that murmur at a routine visit and your dog feels completely like himself. Maybe you've already lived through one bad night and the words you got were "congestive heart failure."
Either way you're here for the same reason: you want to know what watching his heart at home actually looks like, day after ordinary day, and how to tell a bad moment apart from a real change.
First, what did the vet actually hear?
A murmur is just a sound: blood moving through the heart in a way that's turbulent instead of smooth.
In most dogs, especially smaller and older ones, the reason is a valve gone slightly leaky with age, so a little blood slips backward with each beat and makes noise on the way through.
It's the most common heart problem dogs get, and it tends to move slowly.
The "grade" your vet mentioned is loudness, nothing more. A louder murmur can mean more leak, and a softer one often means less, but the sound alone does not tell you how the heart is coping.
That part comes from imaging.
A scan or an X-ray shows whether the heart is starting to enlarge, and enlargement is the thing that actually matters.
The murmur is the doorbell. The imaging tells you who's at the door.
So a murmur on its own is not an emergency, and plenty of dogs live comfortably for years with one.
What you're doing at home is watching for the early signs that the heart is beginning to struggle, so you can carry them to the one person who can check.
What's the one number that matters most?
Count the breaths your dog takes in a minute while he's fully asleep, and you're holding the single most useful heart number there is.
Here's why vets lean on it so hard.
When a diseased heart starts to fall behind, fluid can begin backing up into the lungs. Long before any cough or crisis, that fluid makes each breath a little less efficient, and the body's quiet fix is to breathe a little faster. So the number creeps up.
That creep is your early-warning system. A rising sleeping breath rate can flag the slide toward heart failure before he shows any outward sign of trouble.
That head start is often the whole difference between a calm phone call in the afternoon and a frightening dash to the emergency clinic at midnight.
Here's the rule of thumb most vets use. While he's asleep, under about 30 breaths a minute is the reassuring zone, and a well-managed heart usually sits comfortably below that.
A rate that keeps landing above 30, or that climbs well past his own usual number, is your cue to call.
Breathing that looks laboured while he rests, or a rate that keeps climbing and won't settle, is a reason to call now rather than in the morning.
How do you count it, and why start tonight?
The number only means something once you know his normal. His normal might be 16. It might be 22. The threshold is a backstop; the drift away from his own baseline is the real signal, and you can only see a drift if you know where he started.
So the best night to begin is tonight, while he's steady and nothing is wrong.
A week or two of boring, ordinary counts is the most valuable thing you'll ever collect on this, because it teaches you exactly what settled looks like for this particular dog.
The method is simple:
- Wait until he's properly asleep, not just lying down. A panting, resting, or dreaming dog gives you a useless number. You want quiet, deep sleep.
- Watch his chest or his side. One breath is one rise and one fall together, in and out. Not two.
- Count for a full thirty seconds and double it. This is the small step everyone wants to skip, and it's the one that decides whether your number means anything. A miscount over fifteen seconds gets multiplied by four; over thirty, the same slip barely moves the total.
- Write it down with the date. A note on your phone is plenty. A place built for it makes the trend easier to see, and our free pet vitals tracker will log it and draw the line for you, and it will always be free.
Do that a few times a week while things are calm, and every night if your vet asks you to or if you've had a recent scare.
What you're building, one boring entry at a time, is a quiet picture of his normal. So the day it starts to climb, you'll catch it early.
We go deeper on this single number in our guide to what your dog's resting respiratory rate is telling you.
What about taking his pulse?
The breathing count is the workhorse. His heartbeat is the useful second skill, worth learning even if you reach for it less often.
There are two easy places to find it. The most reliable is the femoral pulse, on the inside of the back leg where the thigh meets the body.
Rest two fingers gently in that soft hollow and press lightly until you feel the beat. The other spot is the heartbeat itself: lay your palm flat against his left side, just behind the elbow, and you'll usually feel it thump.
Once you've found it, count for fifteen seconds and multiply by four, or count a full thirty and double it if he'll hold still.
Normal covers a wide range, because size changes everything.
A big, calm dog at rest might sit somewhere around 60 to 100 beats a minute.
A small dog runs faster, often 100 to 140, and toy breeds and puppies faster still.
There is no single right number, only his usual number, which is one more reason to check it a few times while he's healthy and relaxed.
It's completely normal for a dog's heart to speed up as he breathes in and slow down as he breathes out.
Under your fingers it can feel alarmingly uneven. In a dog, that gentle back-and-forth is usually the sign of a healthy heart rather than a failing one. It's the steady, metronome-flat beat that's more worth mentioning to your vet.
If the rhythm feels truly chaotic, or if you're feeling far fewer pulses at the leg than heartbeats at the chest, note it and bring it up. That mismatch is worth a professional ear.
And if the pulse never quite clicks for you, don't lose a minute of sleep over it. Plenty of devoted owners never get comfortable finding it, and their dogs do beautifully on the breathing count alone.
We looked at how well the gadgets that claim to read heart rate actually hold up in our piece on collar heart-rate accuracy.
What else is worth watching?
A struggling heart shows itself in more than one number. None of these means disaster on its own, but written down and dated, together they hand your vet a picture no single visit could.
- Restless nights and a change in how he sleeps. This is the same watching that gives you the breath count, so it costs you nothing extra. A dog whose lungs are starting to hold fluid often sleeps worse: shifting around, unable to settle, sometimes resting propped up on his chest instead of flopped on his side. A dog who begins refusing to lie down flat at all, choosing to sit up to breathe, needs to be seen soon. Breathing is simply easier upright when there's fluid in the way.
- A new or changing cough. A murmur plus a cough does not add up to a heart cough. Plenty of dogs cough from an irritated windpipe or airways rather than the heart, and that's especially common in the same small breeds that get leaky valves. Heart medication won't quiet that kind of cough. So if a cough turns up or changes, film a few seconds of it on your phone and let your vet sort out where it's coming from, but don't read it as proof of heart failure on its own. The breathing rate stays the more trustworthy heart signal.
- Tiring sooner than he used to. Stopping early on the usual walk, lagging behind, or lying down partway through a game is worth noting, especially when it's new.
- Fainting or collapse. A brief blackout, even if he pops back up looking fine, is not something to watch and wait on. Call your vet about any fainting spell.
- Gum colour. Healthy gums are pink. Gums that turn blue, grey, or very pale mean he isn't moving oxygen the way he should, and that one is an emergency.
- Weight, in both directions. A sudden gain over a few days can be retained fluid. A slow loss over weeks can be the muscle wasting that advanced heart disease brings on. Weigh him weekly and keep the numbers. For a small dog, a baby scale works well.
- A swelling belly. If his abdomen looks rounder or feels tight and firm, that can be fluid pooling where it shouldn't. Mention it promptly.
- His medications. If your vet has started heart medication, log every dose and every missed one. Note anything odd that follows, like a new upset stomach. A couple of the common heart drugs work by clearing extra fluid, so they'll have him drinking and peeing more than usual, and that part is expected. Tell your vet if it seems extreme. And never adjust a dose on your own. With heart medication in particular, that call belongs to your vet, every single time.
That's a lot to keep track of, and you don't have to. Ask your vet which one or two things matter most for your dog right now, and follow those faithfully.
A breath count logged every few days beats a heroic week of six measurements you then abandon.
Where does the technology fit in?
You can't count breaths while you're at work, and you can't hover over a sleeping dog at 3am without wrecking your own rest.
That's the exact gap the technology is built to fill.
Not replacing your attention, extending it into the hours you can't be in the room.
Some collars now log a dog's sleeping breathing rate on their own through the night, and a few estimate heart rate too, using motion sensors while he lies still.
Their accuracy is still being pinned down, and independent studies so far call them close with a small margin rather than perfect, so treat the readout as a helpful trend line, not a verdict.
A simple home camera does a quieter version of the same job, letting you check his breathing and comfort from anywhere and catch that cough on video without standing over him.
None of these diagnose anything. At best they catch a change a little sooner, so you can bring it to your vet, who examines your dog and makes the call.
So the rule for buying is the same one that keeps gadgets out of drawers: a device earns its place only when it covers an hour you can't, or captures a number your vet wants that you can't reliably get by hand.
Bought for that reason, it can be a real comfort.
Bought for any other, it's clutter.
We lay out what the sensors can and can't do in how pet health wearables work.
When do you stop watching and just call?
Monitoring is for trends. Some things are not trends, and they can't wait for tomorrow's count. Call your vet, or an emergency clinic, right away if you see any of these:
- Laboured or open-mouthed breathing while he's resting
- Gums that look blue, grey, or white
- Fainting or collapse, even if he seems fine a moment later
- A belly that has turned swollen and hard
- A breath rate that has jumped well above his baseline and won't settle
- A cough that turns constant, or comes with obvious effort to breathe
If you're standing in the kitchen at midnight, not sure whether this counts - make the call.
No good vet has ever been annoyed with an owner for paying close attention to a heart.
The worst case is a few minutes of reassurance, and where a heart is involved, reassurance is always worth the phone call.
Before the next time you count
You don't need to become a cardiologist to take good care of a dog with a heart condition.
You need one number you check while he sleeps, a feel for his normal, and the nerve to speak up when something drifts.
Those three words circled on the printout make a great deal more sense now than they did in the exam room.
And the thing you're doing right now, sitting close in a quiet house, counting under your breath, is not the small gesture it feels like.
For his heart, it might be the biggest thing you've got.
Is there something about your dog's heart you're still not sure how to watch for? Ask us in the comments and we'll cover it.
Part of our condition monitoring guides. Start from the top with health monitoring for a dog or cat with a chronic condition, or, if your dog is getting on in years, our guide to monitoring a senior dog. Wondering what all this watching adds up to in time and money? See the real cost of pet health tech.