Heart Disease in Dogs and Cats: Common Warning Signs

Picture of Shelby Valentine

Shelby Valentine

February is a month full of hearts — cards, candy, and reminders to cherish the ones we love. But it’s also a good time to think about a different kind of heart: your pet’s.

As veterinarians, one of the most important conversations we have with pet owners is about heart health. Heart disease in dogs and cats can develop quietly over time, often without obvious symptoms in the early stages. The good news? With early detection and proper care, many pets with heart disease can live comfortable, happy lives for years.

Let’s talk about what to watch for — and how we can protect your pet’s heart together.

What Is Heart Disease in Pets?

Heart disease refers to conditions that affect the structure or function of the heart. It can be congenital (present at birth) or acquired over time.

In dogs, we most commonly see:

  • Degenerative valve disease (especially in small breeds)

  • Dilated cardiomyopathy (DCM), often in larger breeds

In cats, we most often diagnose:

  • Hypertrophic cardiomyopathy (HCM), a thickening of the heart muscle

These conditions affect how efficiently the heart pumps blood throughout the body. When the heart can’t do its job properly, fluid can build up in the lungs or abdomen, leading to serious complications.

Early Warning Signs You Shouldn’t Ignore

One of the hardest things about heart disease is that early signs can be subtle. Many pets appear completely normal at first.

Here are some common warning signs we encourage pet owners to watch for:

In Dogs:

  • Persistent coughing (especially at night or after activity)

  • Decreased stamina or tiring easily

  • Rapid or labored breathing

  • Fainting or collapse

  • Abdominal swelling

In Cats:

  • Increased respiratory rate (breathing faster than normal at rest)

  • Open-mouth breathing (an emergency)

  • Lethargy or hiding more than usual

  • Sudden hind limb weakness or paralysis (possible blood clot)

  • Decreased appetite

If your pet’s behavior feels “off,” even in a small way, trust that instinct. You know your pet better than anyone.

Why Early Detection Matters

Heart disease is often progressive, meaning it worsens over time. However, catching it early can make an enormous difference.

During annual (or semiannual) exams, we listen carefully for:

  • Heart murmurs

  • Irregular heart rhythms

  • Changes in breathing patterns

If we hear something concerning, we may recommend further diagnostics such as:

  • Chest X-rays

  • Blood pressure measurement

  • Bloodwork

  • An echocardiogram (ultrasound of the heart)

These tools allow us to diagnose heart disease before it becomes advanced — and that’s where we can truly change the outcome.

Early treatment may include medications to:

  • Reduce fluid buildup

  • Support heart function

  • Manage blood pressure

  • Prevent complications

The sooner we intervene, the better we can protect your pet’s quality of life.

Pets at Higher Risk

Some pets are more likely to develop heart disease.

In dogs:

  • Small breeds (like Cavaliers, Dachshunds, Chihuahuas) are prone to valve disease.

  • Large breeds (like Dobermans, Great Danes, Boxers) are more prone to DCM.

In cats:

  • Maine Coons, Ragdolls, and some other breeds have a genetic predisposition to HCM.

Age is also a factor. Senior pets are more likely to develop acquired heart conditions, which is why consistent wellness exams become even more important as pets grow older.

When It Becomes an Emergency

If your pet shows any of the following, seek veterinary care immediately:

  • Difficulty breathing

  • Collapse or fainting

  • Pale or blue gums

  • Sudden inability to use the back legs (especially in cats)

  • Severe lethargy

These can indicate congestive heart failure or a blood clot — both of which require urgent medical attention.

When in doubt, it is always better to call.

Loving Their Heart as Much as They Love Yours

Our pets give us unconditional love every single day. They greet us at the door, sit beside us when we’re sad, and fill our homes with joy.

Taking care of their hearts is one of the most meaningful ways we can return that love.

Heart disease doesn’t have to mean hopelessness. With early detection, consistent monitoring, and thoughtful treatment, many pets continue to thrive for years after diagnosis.

At 1st Pet, we’re here to partner with you — from routine wellness exams to advanced diagnostics and long-term management. Whether you’ve noticed subtle changes or simply want peace of mind, we’re always happy to evaluate your pet’s heart health.

If you’ve noticed coughing, fatigue, changes in breathing, or anything that feels unusual — or if it’s simply time for your pet’s annual exam — contact 1st Pet today.

Let’s protect the heart that loves you most.

1stPet is Your Go-To For Unmatched Veterinary Care

 Unexpected pet emergencies can be stressful, but with the right insurance coverage and an expert veterinary team, you can have peace of mind. At 1stPet, we’re available around the clock to provide compassionate emergency care whenever you need it. Our dedicated team is committed to helping your pet feel better as quickly as possible. Whether you’re facing an unanticipated situation or simply seeking reassurance for the future, you can rely on 1stPet for expert care at every stage. You and your pet deserve the best.