Heart Disease in Older Dogs — Symptoms and Care

Hearing that your dog has a heart condition can feel like the ground has shifted beneath you. The heart carries such powerful symbolism that a diagnosis involving it can trigger immediate fear and grief. But heart disease in dogs, like many conditions in veterinary medicine, exists on a broad spectrum. Some dogs have heart murmurs that are monitored for years without ever progressing to a point that requires treatment. Others may need medication and lifestyle adjustments but go on to live comfortable, joyful lives.

This guide offers an educational overview of the most common heart conditions affecting senior dogs, the signs that warrant veterinary attention, and the practical ways you can support your dog's heart health at home. The goal is to replace fear with understanding, so you can be a calm, informed advocate for your aging companion.

Common Heart Conditions in Senior Dogs

Degenerative Mitral Valve Disease

This is the most frequently diagnosed heart condition in dogs, and it is especially common in small to medium breeds like Cavalier King Charles Spaniels, Dachshunds, Miniature Poodles, and Chihuahuas. The mitral valve, which sits between the left atrium and left ventricle, gradually thickens and deteriorates over time. As it loses its ability to close tightly, blood leaks backward through the valve with each heartbeat, a process called regurgitation.

In the early stages, the heart compensates for this leakage by enlarging, which keeps blood flowing effectively to the body. During this compensated phase, many dogs have no symptoms at all. Their veterinarian may detect a heart murmur during a routine examination, but the dog feels fine. As the disease progresses, the heart's ability to compensate eventually reaches its limit, potentially leading to congestive heart failure.

Dilated Cardiomyopathy

Dilated cardiomyopathy, or DCM, is a condition in which the heart muscle weakens and the chambers enlarge. This reduces the heart's ability to pump blood effectively. It is more common in large and giant breeds, including Doberman Pinschers, Great Danes, Irish Wolfhounds, and Boxers. DCM can progress more rapidly than valve disease and may sometimes present with minimal warning.

Arrhythmias

Heart rhythm abnormalities become more common as dogs age. Some arrhythmias are benign and require no treatment, while others can compromise heart function or increase the risk of sudden complications. Arrhythmias may occur alongside other heart conditions or on their own. Your veterinarian may detect an irregular rhythm during a physical exam or through an electrocardiogram.

Recognizing the Signs

Heart disease in its early stages often produces no visible symptoms. This is why regular veterinary exams are so valuable. A skilled veterinarian can detect a heart murmur, an arrhythmia, or subtle changes in heart sounds long before you would notice anything at home. As heart disease progresses, however, certain signs become apparent.

Coughing

A persistent cough is one of the most recognized signs of heart disease in dogs. It may be worse at night, after exercise, or when your dog lies down. The cough is often soft and hacking, different from the sharp cough of a respiratory infection. It occurs because an enlarged heart presses on the airways, or because fluid accumulates in or around the lungs.

Breathing Changes

Watch your dog's breathing rate when they are resting or sleeping. A normal resting respiratory rate for dogs is generally under thirty breaths per minute. If you notice faster breathing, labored breathing, or breathing with visible effort (belly-pumping or flared nostrils), these are signs that warrant prompt veterinary attention. Learning to count your dog's resting respiratory rate is one of the most valuable monitoring skills you can develop.

Exercise Intolerance

A dog whose heart is not pumping effectively may tire more easily during walks, lag behind, or refuse activities they previously enjoyed. They may need more frequent rest breaks or seem winded after mild exertion. While some degree of slowing down is normal with age, a noticeable reduction in stamina should be discussed with your vet.

Fainting or Collapse

Some dogs with heart disease experience fainting episodes, called syncope. These typically involve a sudden loss of consciousness followed by rapid recovery. They can occur during excitement, exercise, or coughing episodes. While brief, syncope episodes should always be reported to your veterinarian.

Fluid Retention

Congestive heart failure can cause fluid to accumulate in the lungs (pulmonary edema) or in the abdomen (ascites). Abdominal fluid buildup gives the belly a swollen or distended appearance. Fluid in the lungs causes coughing and breathing difficulty. Both are signs that heart disease has progressed and needs immediate veterinary attention.

Monitoring at Home: Resting Respiratory Rate

One of the most useful things you can do at home is regularly monitor your dog's resting respiratory rate. This is the number of breaths per minute when your dog is sleeping or resting quietly. Count the number of times the chest rises and falls over thirty seconds, then multiply by two.

Establish your dog's baseline rate when they are healthy and at rest. For most dogs, this is between fifteen and thirty breaths per minute. Record this number. If you notice a consistent increase of more than twenty percent above the baseline, or if the resting rate exceeds forty breaths per minute, contact your veterinarian. Changes in resting respiratory rate are often one of the earliest indicators that heart disease is progressing or that a medication adjustment is needed.

Lifestyle Modifications for Heart Health

Dietary Considerations

Sodium management is an important part of supporting a dog with heart disease. While extreme sodium restriction is typically reserved for dogs in congestive heart failure, reducing excessive sodium intake is generally recommended for all dogs with heart disease. This means avoiding salty human foods, high-sodium commercial treats, and table scraps.

High-quality protein supports muscle maintenance, including the heart muscle itself. Omega-3 fatty acids from fish oil may provide anti-inflammatory benefits and have been studied for their potential to reduce the risk of arrhythmias. Some veterinarians also recommend supplementation with taurine and L-carnitine, amino acids that play roles in heart muscle function.

Appropriate Exercise

Dogs with heart disease benefit from gentle, consistent exercise rather than strenuous bursts of activity. Short, easy walks on flat terrain are usually appropriate and help maintain muscle tone, support circulation, and contribute to your dog's mental well-being. Your veterinarian can advise on the appropriate level of activity for your dog's specific condition.

Avoid exercising your dog in hot or humid conditions, as the heart has to work harder to cool the body. Watch for signs of fatigue during walks, including heavy panting, slowing down, or stopping to rest. Let your dog set the pace and end the walk before they seem tired rather than pushing them to keep going.

Weight Management

Maintaining a healthy weight is particularly important for dogs with heart disease. Excess body weight increases the workload on an already compromised heart. If your dog is overweight, your veterinarian can help you develop a safe, gradual weight loss plan that takes their cardiac condition into account.

Stress Reduction

Emotional stress and excitement increase heart rate and blood pressure, placing additional demands on the heart. While you cannot and should not eliminate all excitement from your dog's life, minimizing unnecessary stressors can help. Maintain a calm, predictable routine, avoid situations that cause extreme excitement or anxiety, and provide a quiet resting space where your dog can retreat.

Understanding Medications

If your veterinarian prescribes heart medications, understanding their general purposes can help you appreciate why each one matters. Common categories include diuretics that help remove excess fluid from the body, ACE inhibitors that reduce the workload on the heart, positive inotropes that help the heart pump more effectively, and antiarrhythmics that manage abnormal heart rhythms.

Consistency is critical with heart medications. Give them at the same times each day as directed, and do not skip doses or stop medications without consulting your veterinarian. Keep a medication schedule posted in a visible location to help everyone in the household stay consistent.

When to Seek Urgent Veterinary Care

Certain signs in a dog with known heart disease require prompt veterinary attention. Contact your veterinarian or emergency clinic if your dog shows a resting respiratory rate consistently above forty breaths per minute, sudden difficulty breathing or gasping, blue-tinged gums or tongue, a sudden collapse or fainting episode, complete loss of appetite lasting more than twenty-four hours, or sudden severe lethargy or weakness.

Having a plan in place for emergencies provides peace of mind. Know the location and hours of your nearest emergency veterinary clinic, and keep your veterinarian's after-hours contact information readily accessible.

The Power of Partnership

Managing heart disease in your senior dog is a partnership between you, your dog, and your veterinary team. Your daily observations, your commitment to medications and monitoring, and your willingness to adapt your dog's lifestyle all contribute to the best possible outcome. With attentive care and appropriate veterinary guidance, many dogs with heart disease continue to enjoy comfortable, love-filled lives alongside the people who matter most to them.