Dog Heart Health: Signs, Prevention & Care Tips

You notice your dog tires faster on walks. The cough that started a few weeks ago hasn’t gone away. Maybe your vet mentioned a heart murmur at the last checkup, and now you’re wondering what comes next.

Heart disease in dogs is more common than most Australian owners realise. Research shows up to 10% of dogs aged 5 to 8 years have some form of heart disease, climbing to 30% in dogs over 13 years old. But here’s what matters most: early detection and the right care can add quality years to your dog’s life. You don’t need to feel overwhelmed. Understanding the warning signs, knowing when to act, and building heart-healthy habits into daily routines makes all the difference. This guide walks you through the signs to watch for, prevention steps that work, foods that support heart function, and how to care for a dog already diagnosed. Whether you’re starting fresh with a new puppy or supporting a senior dog, you’ll find practical actions you can take today.

Quick Answers: What You Need to Know About Dog Heart Disease

• What is it? Heart disease affects how your dog’s heart pumps blood. It includes valve problems, heart muscle weakness, and rhythm issues. It can be present from birth or develop with age.
• Why it matters: The heart supplies oxygen to every organ. When it struggles, your dog feels tired, breathless, and unwell. Early care slows disease progression.
• Common signs: Persistent coughing (especially at night), breathing faster than normal when resting, tiring quickly, fainting, or swollen belly.
• Risk factors: Older dogs, certain breeds (Cavalier King Charles Spaniels, Dobermans, Boxers), obesity, poor dental health, and lack of parasite prevention.
• First steps: Book a vet check if you notice breathing changes or reduced energy. Monitor resting breathing rate at home. Keep dental health strong.
• Can it be managed? Yes. With medication, diet adjustments, weight control, and regular checkups, many dogs live happily for years after diagnosis.
• Prevention works: Maintain healthy weight, feed quality food, keep teeth clean, stay active, and attend annual vet visits.

What Dog Heart Disease Means

Heart disease in dogs describes conditions where the heart can’t pump blood effectively. It’s not one single illness. The term covers valve problems, weakened heart muscle, rhythm abnormalities, and structural defects.

Your dog’s heart has four chambers. Blood flows through valves between these chambers. When valves leak, muscles weaken, or chambers enlarge, the heart works harder but achieves less.

Some dogs are born with heart problems (congenital). Others develop heart disease as they age (acquired). The most common type in Australia is myxomatous mitral valve disease (MMVD), which affects the valve between the left chambers. Large breeds often face dilated cardiomyopathy (DCM), where the heart muscle stretches and weakens.

Heart disease progresses in stages. Stage A means a dog is at risk but shows no changes. Stage B means structural changes exist but no symptoms appear. Stage C involves symptoms like coughing or breathlessness. Stage D is advanced heart failure.

Why this matters: catching disease at Stage B, before symptoms start, gives you time to slow progression. Regular vet visits and knowing your dog’s breed risks help with early detection.

Signs of Heart Disease in Dogs

Early Signs (Don’t Ignore These)

These subtle changes often appear months before obvious symptoms:

• Cough that lingers: Especially after excitement, exercise, or at night. It sounds dry or hacking.
• Tiring sooner: Your dog used to walk 30 minutes easily but now wants to turn back at 15.
• Restless sleep: Getting up and down, unable to settle, or sleeping sitting up.
• Faster breathing at rest: Count breaths while your dog sleeps. Normal is 16 to 24 breaths per minute. Above 30 needs attention.
• Reduced interest in play: Less enthusiasm for fetch, toys, or running around.

Urgent Red Flags (See a Vet Today)

If your dog shows any of these, book an appointment the same day:

• Laboured breathing: Working hard to breathe, chest heaving, or breathing with mouth open when resting.
• Pale or blue gums: Lift your dog’s lip. Gums should be pink. Pale, white, or blue means poor oxygen flow.
• Collapse or fainting: Even brief episodes signal serious blood flow problems.
• Swollen belly: Fluid buildup in the abdomen feels tight and distended.
• Severe weakness: Unable to stand, walk, or coordinate movements.

Recognising these signs early means you can check symptoms and get professional guidance before the condition worsens.

What Causes Heart Disease in Dogs

Risk Factors You Can Control

• Obesity: Extra weight forces the heart to pump harder. Even 10% over ideal weight increases heart strain.
• Poor dental health: Bacteria from gum disease enter the bloodstream and can damage heart valves. 80% of dogs over 3 years show dental disease (source: Pittwater Animal Hospital).
• Lack of exercise: Inactive dogs develop weaker hearts and gain weight faster.
• Heartworm exposure: More common in northern Australia. Preventatives are essential.

Risk Factors You Can’t Control

• Age: Heart disease becomes more common after age 10.
• Breed: Some breeds face higher genetic risk (see below).
• Sex: Male dogs develop heart disease slightly more often than females.

Common Heart Conditions

Myxomatous Mitral Valve Disease (MMVD): Makes up 75% of canine heart disease cases. The mitral valve thickens and leaks. Blood flows backward instead of forward. Small to medium breeds are most affected.

Dilated Cardiomyopathy (DCM): The heart chambers enlarge and walls thin. The heart can’t contract properly. Large breeds face higher risk. Some cases link to grain-free diets high in legumes (source: Morris Animal Foundation).

Congenital Heart Defects: Present at birth. Include holes in the heart, narrowed valves, or abnormal blood vessel connections. Often detected in young puppies during vaccinations.

Heartworm Disease: Caused by parasites transmitted through mosquitoes. Preventable with regular medication.

Breeds at Higher Risk

These breeds should have heart checks from young adulthood:

• Cavalier King Charles Spaniels (50% develop heart murmurs by age 5)
• Doberman Pinschers
• Boxers
• Great Danes
• Irish Wolfhounds
• Cocker Spaniels
• Dachshunds
• Miniature Schnauzers
• Pomeranians
• Chihuahuas

If your dog belongs to one of these breeds, annual heart screenings from age 4 help catch problems early.

How Vets Diagnose Heart Disease

Physical Examination

Your vet listens to your dog’s heart with a stethoscope. They’re checking for:

• Heart murmurs: A whooshing sound between the normal “lub-dub.” Murmurs are graded 1 to 6. Grade 1 is barely audible. Grade 6 is loud and can be felt through the chest wall (source: SASH Vets).
• Heart rhythm: Regular or irregular beats.
• Lung sounds: Crackles suggest fluid buildup.

A murmur doesn’t always mean heart disease. Young puppies often have innocent murmurs that disappear by 4 to 5 months. But any murmur needs follow-up.

Diagnostic Tests

Chest X-rays: Show heart size and shape. Reveal fluid in lungs. Track changes over time using Vertebral Heart Score (VHS).

Echocardiogram (Heart Ultrasound): The gold standard test. Shows valve function, chamber size, blood flow direction, and heart muscle strength. Performed by a cardiologist.

Electrocardiogram (ECG): Records electrical activity. Detects abnormal rhythms (arrhythmias).

Blood Pressure Measurement: High blood pressure worsens heart disease.

Blood Tests: Check organ function. Measure biomarkers like BNP (brain natriuretic peptide) that rise with heart failure.

Holter Monitor: A wearable ECG device your dog wears at home for 24 hours. Captures rhythm abnormalities that don’t show up during short clinic visits.

What Happens After Diagnosis

Your vet will explain:

• Disease stage (A, B, C, or D)
• Whether medication is needed now
• Monitoring schedule (usually every 3 to 6 months)
• Home tracking you should do

Prevention Plan for Lifelong Heart Health

1. Maintain Ideal Weight

Check your dog’s body condition monthly. You should feel ribs easily under a thin fat layer. From above, see a defined waist. From the side, see a tucked-up belly.

If your dog carries extra weight:

• Measure food portions instead of free-feeding
• Use vegetables as low-calorie treats
• Increase activity gradually
• Work with your vet on a weight loss plan

2. Feed Quality, Balanced Nutrition

Choose commercial foods that meet WSAVA guidelines. Look for:

• Named protein source as first ingredient
• No excessive legumes (peas, lentils) in top ingredients
• Appropriate for life stage
• Made by established manufacturers

Avoid boutique, exotic, or grain-free (BEG) diets unless medically necessary. These have been linked to DCM in some dogs.

3. Keep Teeth and Gums Healthy (Cardiovascular Care for Dogs)

Dental disease bacteria damage heart valves. Prevention matters:

• Brush teeth 3 to 5 times weekly with dog toothpaste
• Offer dental chews or raw meaty bones (supervise)
• Book professional dental cleans when your vet recommends
• Watch for bad breath, red gums, or reluctance to eat hard food

Regular dental care is one of the most overlooked aspects of cardiovascular care for dogs.

4. Stay Active Together

Exercise keeps hearts strong, maintains healthy weight, and reduces stress.

Dogs need:

• Daily walks appropriate for age and breed
• Mental stimulation through training or puzzle toys
• Social play with other dogs when safe
• Swimming for low-impact cardio

Adjust for age:

• Puppies: Short, frequent sessions
• Adults: 30 to 60 minutes daily
• Seniors: Gentle walks, avoid overheating

5. Prevent Parasites

Heartworm: Endemic in Queensland and northern NSW. Monthly preventatives are essential. One missed dose creates risk.

Fleas and ticks: Some carry diseases that stress the heart. Year-round prevention recommended in most of Australia.

6. Schedule Annual Vet Checks

Regular exams catch problems early. Your vet checks:

• Heart sounds and rhythm
• Breathing rate and effort
• Weight and body condition
• Dental health
• Blood pressure (for dogs over 7 years)

For at-risk breeds or dogs over 10, consider twice-yearly visits.

Foods That Support Dog Heart Health

Nutritional Principles

Heart-healthy nutrition focuses on:

• Moderate sodium: Excess salt causes fluid retention. Choose lower-sodium foods.
• High-quality protein: Maintains muscle mass. Essential as heart disease often causes muscle loss.
• Omega-3 fatty acids: Reduce inflammation, support blood vessel health. EPA and DHA are most beneficial.
• Taurine and L-carnitine: Amino acids that support heart muscle function.
• Antioxidants: Vitamin E, selenium, and other antioxidants fight oxidative stress.

Heart-Healthy Whole Foods

Add these to your dog’s diet (check portions with your vet):

Omega-3 Rich Options:

• Sardines (canned in water, no salt)
• Salmon (cooked, no bones)
• Green-lipped mussels
• Chia seeds (ground)
• Flaxseed oil

Taurine Sources:

• Chicken hearts
• Beef heart
• Eggs
• Turkey

Antioxidant Foods:

• Blueberries
• Spinach (cooked)
• Carrots
• Sweet potato
• Broccoli (small amounts)

Other Beneficial Foods:

• Bone broth (low sodium)
• Plain yoghurt
• Pumpkin

What to Avoid

High-sodium foods:

• Processed meats
• Cheese
• Commercial treats
• Table scraps
• Canned vegetables with added salt

Foods linked to DCM:

• Diets where peas, lentils, or potatoes are top ingredients
• Exotic proteins without balanced formulation
• Home-cooked diets without veterinary nutritionist guidance

Prescription Heart Diets

Dogs with diagnosed heart disease often benefit from therapeutic diets. These feature:

• Restricted sodium and chloride
• Enhanced taurine and L-carnitine
• Omega-3 supplementation
• Controlled potassium

Your vet prescribes these based on disease stage and other health conditions.

Managing Dog Heart Disease: Daily Care Plan

Medication Routines

Most dogs with heart disease take daily medication. Common types include:

Pimobendan (Vetmedin): Helps the heart pump more effectively. Reduces strain. Often the first medication started.

Diuretics (Frusemide): Remove excess fluid from lungs and body. Reduce breathing difficulty.

ACE Inhibitors (Enalapril, Benazepril): Lower blood pressure. Reduce workload on the heart.

Medication Tips:

• Give at the same times daily
• Use a pill organiser to track doses
• Give Pimobendan on an empty stomach (1 hour before food)
• Write down doses given to avoid mistakes
• Never skip doses
• Contact your vet if side effects appear

Exercise Guidelines

Continue activity but adjust intensity:

Do:

• Short, gentle walks
• Swimming in warm weather
• Mental enrichment at home
• Play sessions your dog can stop when tired

Avoid:

• High-intensity running
• Excessive heat or humidity
• Overexcitement
• Stressful situations

Watch for fatigue. If your dog stops, sits down, or breathes heavily, end the activity.

Heat Management

Dogs with heart disease struggle to regulate temperature. In Australian summers:

• Exercise early morning or late evening
• Provide constant access to cool water
• Use cooling mats
• Avoid hot cars entirely
• Watch for excessive panting

Home Monitoring

Track these weekly (or daily if your vet advises):

Resting Respiratory Rate (RRR):

1. Wait until your dog is asleep
2. Count breaths for 60 seconds (one rise and fall = one breath)
3. Normal: 16 to 24 breaths per minute
4. Alert: Above 30 breaths per minute at rest

If RRR stays above 30 for more than 24 hours, contact your vet the same day.

Weight:

• Weigh weekly
• Use the same scale at the same time of day
• Sudden weight gain (fluid) or loss (muscle wasting) both need attention

Appetite and Energy:

• Note changes in food interest
• Track energy levels during walks
• Watch for new symptoms like coughing or fainting

Follow-Up Visits

Expect checkups every 3 to 6 months. Your vet will:

• Listen to heart and lungs
• Check weight and body condition
• Review medications and adjust doses
• Perform chest X-rays or blood tests as needed
• Discuss any changes you’ve noticed

Common Mistakes to Avoid

Waiting too long to see a vet: Breathing changes or reduced energy need same-day attention. Don’t wait until your dog collapses.

Skipping medications: Missing even a few doses can cause heart failure to worsen rapidly.

Feeding high-salt treats: One salty treat undoes careful diet management.

Overexercising: Pushing your dog too hard strains the heart. Watch for fatigue signals.

Ignoring dental disease: Infected teeth damage heart valves. Professional cleans prevent this.

Free-feeding: Overweight dogs face higher heart disease risk. Measure meals.

Missing follow-ups: Regular monitoring catches problems before they become crises.

Heart Health Checklist

Use this monthly checklist to protect your dog’s heart:

□ Teeth brushed at least 3 times this week
□ Weight stable and within healthy range
□ Daily walks completed
□ Flea, tick, and heartworm prevention given on schedule
□ Resting breathing rate checked (and below 30)
□ No persistent coughing, especially at night
□ Good energy levels during exercise
□ Appetite normal
□ Medications given on time (if applicable)
□ Vet appointment scheduled if due

4-Week Heart Health Starter Plan

Follow this simple plan to build heart-protective habits:

Continue all habits from previous weeks as you progress.

FAQs: Dog Heart Disease

How do I know if my dog’s cough is serious?

Coughs linked to heart disease worsen at night, after exercise, or when lying down. They sound dry and persist for weeks. If your dog coughs for more than a few days, particularly if accompanied by tiredness or faster breathing, check symptoms and book a vet visit. Urgent signs include coughing up foam, breathing difficulty, or blue gums.

Can heart disease in dogs be cured?

Most heart disease can’t be cured but can be managed effectively. Medications, diet changes, and lifestyle adjustments slow progression. Many dogs live comfortably for years after diagnosis. Some congenital defects can be corrected surgically when caught early.

What foods are best for a dog with heart disease?

Focus on high-quality protein, moderate sodium, and omega-3 fatty acids. Good choices include fresh fish (sardines, salmon), lean meats, eggs, and vegetables. Avoid processed foods, cheese, and salty treats. Your vet may prescribe a therapeutic heart diet formulated with restricted sodium and added taurine.

How often should my dog see the vet for heart disease?

Dogs on heart medications typically need checkups every 3 to 6 months. Your vet listens to the heart, checks weight, adjusts medications, and may perform X-rays or blood tests. More frequent visits are needed if symptoms worsen or new problems develop.

Is exercise safe for dogs with heart disease?

Yes, but adjust intensity. Gentle daily walks benefit most dogs with heart disease. Avoid high-intensity running, extreme heat, and overexcitement. Watch for fatigue. Stop activity if your dog sits down, breathes heavily, or seems tired. Swimming provides low-impact exercise in warm weather.

What is a heart murmur and is it always serious?

A heart murmur is an abnormal sound (whooshing or swishing) heard through a stethoscope. It indicates turbulent blood flow. Not all murmurs are serious. Young puppies often have innocent murmurs that resolve by 5 months. In older dogs, murmurs usually signal valve disease or other heart problems needing evaluation.

Can I prevent heart disease in my dog?

You can reduce risk significantly. Maintain healthy weight, feed quality food, keep teeth clean, exercise daily, prevent heartworm, and attend annual vet checks. Some heart disease is genetic and can’t be prevented, but lifestyle factors make a major difference.

What’s the link between grain-free diets and heart disease?

Research identified a connection between certain grain-free diets (particularly those high in peas, lentils, or potatoes) and dilated cardiomyopathy in dogs (source: Morris Animal Foundation). The exact cause remains unclear. Most veterinary nutritionists now recommend avoiding diets where legumes are primary ingredients unless medically necessary.

How long can dogs live with heart disease?

This varies widely based on disease type, stage at diagnosis, and treatment response. Some dogs live 2 to 3 years or more after diagnosis with good quality of life. Early detection and consistent management improve outcomes. Dogs diagnosed in early stages often do better than those diagnosed after heart failure develops.

What should I feed a dog with both heart disease and kidney disease?

This requires careful balance as kidney diets restrict protein while heart diets maintain it. Work with your vet or a veterinary nutritionist to find the right approach. Usually, kidney disease takes priority if advanced. Your vet will recommend prescription diets designed for both conditions.

Your Dog’s Heart Deserves the Best Care

Heart disease doesn’t mean the end of happy years together. It means adapting, staying alert, and giving your dog the support they need. You’ve learned the warning signs to watch for, prevention steps that protect heart health, and daily care routines that work.

Start with one action today. Count your dog’s resting breathing rate. Book that overdue dental clean. Measure food portions instead of guessing. Small changes build into powerful protection.

Your dog can’t tell you when something feels wrong. They rely on you to notice, to care, and to act. Whether you’re preventing heart disease or managing it, you now have the knowledge to make informed decisions.

Talk to your vet about anything that concerns you. Early intervention changes outcomes. Your commitment to your dog’s heart health can add quality years to their life. And that’s time you’ll both treasure.

Raj Shakya

A passionate dog lover, Raj Shakya has years of experience helping Aussie pet owners manage and overcome common dog training challenges. With a focus on positive reinforcement and practical solutions, Raj is dedicated to making life easier for both dogs and their families by encouraging better behaviour, stronger communication, and happier bonds.