Preventing heart failure in dogs comes down to a handful of consistent habits: keeping up with heartworm prevention, maintaining a healthy weight, feeding a well-balanced diet, staying on top of dental care, and catching early warning signs through routine veterinary screenings. Some risk factors, like breed and genetics, are outside your control, but the preventable causes are significant enough to make a real difference in your dog’s lifespan and quality of life.
Know Your Dog’s Breed Risk
Heart failure in dogs has two main forms, and they tend to split along size lines. Small dogs are most prone to degenerative valve disease, where the heart’s valves gradually thicken and leak, preventing efficient blood flow. Large dogs are more susceptible to dilated cardiomyopathy (DCM), where the heart muscle weakens and the chambers stretch out, reducing the heart’s pumping power.
Cavalier King Charles Spaniels carry by far the highest risk. In a large study of over 300,000 insured dogs, Cavaliers had 16 times the odds of cardiovascular disease compared to Miniature Dachshunds, with 13.6% of the breed developing a heart condition. Maltese dogs had about 5.5 times the odds, followed by Pomeranians (4 times), Chihuahuas (3.8 times), and Shih Tzus (3.4 times). Among larger breeds, Doberman Pinschers, Boxers, Great Danes, and Irish Wolfhounds are well-known for DCM risk.
If your dog belongs to a high-risk breed, that doesn’t guarantee heart failure. It means earlier and more frequent cardiac screening is worth the investment, and it makes every other preventive step on this list more important.
Keep Heartworm Prevention Current
Heartworm infection is one of the most preventable causes of heart failure in dogs, and one of the most devastating when missed. The parasites lodge in the pulmonary arteries and heart, causing permanent damage to blood vessels and eventually leading to right-sided heart failure. Dogs that test positive for heartworm have 3.6 times the risk of right-sided heart failure and 2.8 times the risk of cardiomyopathy compared to dogs that were never infected.
Monthly or injectable preventive medications work by killing heartworm larvae before they mature. Even dogs with gaps in their preventive schedule still benefit substantially. Dogs on monthly prevention had about one-third the risk of testing positive compared to unprotected dogs. Dogs receiving the longer-acting injectable form had an even lower risk, roughly 15% that of unprotected dogs. The takeaway: consistent prevention is ideal, but imperfect prevention is still far better than none. If you’ve fallen behind on doses, restarting protection and getting a heartworm test from your vet is one of the single most impactful things you can do for your dog’s heart.
Maintain a Healthy Body Weight
Excess weight forces your dog’s heart to work harder with every beat. Obesity increases both the volume of blood the heart has to pump and the resistance it pumps against, leading to thickening of the heart walls. In a study of obese dogs, more than half had mildly elevated blood pressure, and all showed signs of impaired heart relaxation on ultrasound. The heart walls physically thickened to compensate for the extra workload.
When those dogs lost weight, the thickened walls measurably thinned. That’s encouraging, but other changes to heart function didn’t fully reverse, which suggests that preventing weight gain in the first place protects the heart more effectively than losing weight later. Your vet can tell you your dog’s body condition score and ideal weight range. For most dogs, you should be able to feel the ribs easily under a thin layer of fat, and see a visible waist when looking from above.
Feed a Balanced, Evidence-Based Diet
Starting in 2018, the FDA investigated reports of DCM in dogs eating certain grain-free diets, particularly those with high proportions of peas, lentils, and potatoes as primary ingredients. Over 90% of the products named in DCM reports were labeled grain-free, and 93% contained peas or lentils as major ingredients. The investigation has not established a definitive cause, and the FDA has described the potential link as “a complex scientific issue that may involve multiple factors.” No further public updates have been issued since December 2022.
The uncertainty itself is worth taking seriously. Until the science is clearer, many veterinary cardiologists recommend choosing diets from manufacturers that employ board-certified veterinary nutritionists, conduct feeding trials, and publish their research. If you’re feeding a grain-free diet without a specific medical reason (such as a confirmed grain allergy), switching to a grain-inclusive food from an established manufacturer is a reasonable precaution.
For breeds prone to DCM, your vet may check blood taurine levels. Taurine is an amino acid that dogs can usually produce on their own, but some dogs on certain diets develop deficiencies that contribute to heart muscle weakness. Supplementation is typically reserved for dogs already diagnosed with DCM or confirmed deficiency rather than given preventively to healthy dogs.
Don’t Neglect Dental Health
Periodontal disease is one of the most overlooked risk factors for heart problems in dogs. A study evaluating the connection found significant associations between the severity of gum disease and the risk of endocarditis (infection of the heart valves) and cardiomyopathy. The likely mechanism is chronic inflammation: bacteria from infected gums enter the bloodstream and can damage heart tissue over time.
Regular dental cleanings, daily tooth brushing (or at least several times per week), and dental chews approved by the Veterinary Oral Health Council all help reduce the bacterial load in your dog’s mouth. Small breeds, which are already at higher risk for valve disease, are also more prone to dental problems, making this doubly important for dogs like Cavaliers, Yorkies, and Chihuahuas.
Get Proactive About Screening
Heart disease in dogs often progresses silently for months or years before any symptoms appear. By the time you notice coughing, exercise intolerance, or rapid breathing, the disease may already be advanced. Early detection changes the timeline significantly.
A blood test measuring a protein called NT-proBNP can flag heart stress before physical symptoms develop. This biomarker rises when the heart muscle is under strain, even before there’s visible damage on an X-ray or obvious signs at home. It’s particularly useful as a screening tool during routine wellness visits, especially for breeds at elevated risk. The test works best when combined with other diagnostics like chest X-rays and echocardiograms rather than as a standalone.
For dogs diagnosed with early-stage valve disease (before any symptoms of heart failure appear), a landmark clinical trial known as the EPIC study showed that starting a specific heart medication reduced heart size within 35 days and delayed the onset of heart failure. Dogs whose hearts shrank more on the medication had significantly better outcomes. This means catching disease in its preclinical stage, when your dog still seems perfectly healthy, opens a window for treatment that doesn’t exist once heart failure sets in. Ask your vet about cardiac screening starting around age 5 to 6 for high-risk breeds, or whenever a murmur is first detected.
Exercise: Protective but Adjustable
Regular physical activity supports cardiovascular fitness in healthy dogs the same way it does in people. Daily walks, play sessions, and opportunities to run help maintain a healthy weight and keep the heart conditioned. There’s no single “prescription” for healthy dogs. Just keep them consistently active at a level appropriate for their breed, age, and size.
If your dog has already been diagnosed with early heart disease but isn’t showing symptoms, moderate exercise is not only safe but potentially beneficial. Veterinary research supports walking sessions of 30 to 50 minutes, three times per week, at a brisk but comfortable pace for dogs in early stages of valve disease. For dogs with stabilized heart failure on medication, lighter walks of 20 to 30 minutes, two to three times per week, are recommended. The key distinction: dogs showing active signs of fluid buildup, labored breathing, or congestion should rest and be stabilized with medication before resuming any exercise program.
Watch for subtle changes during activity. A dog that used to finish a walk easily but now lags behind, pants excessively, or needs to stop and rest may be showing the first signs of reduced cardiac output. These changes often appear during exercise long before they show up at rest.