Heart disease in senior dogs and cats

Heart disease becomes increasingly common as pets age, affecting an estimated 10-15% of all dogs and cats. In senior pets, the heart may struggle to pump efficiently, leading to symptoms that can significantly impact quality of life if left untreated.

The good news is that heart disease in pets is often highly manageable. Understanding the condition helps you recognize problems early and work with your veterinarian to keep your pet comfortable.

How the heart ages

Like all muscles, the heart changes with age. The walls may thicken or thin, valves may wear out and leak, and the electrical system may become less reliable. These changes force the heart to work harder to circulate blood effectively.

The body initially compensates for declining heart function through various mechanisms. By the time symptoms appear, the heart has often been struggling for some time. This is why regular veterinary checkups that include heart assessment are so important for senior pets.

Common heart conditions in dogs

Mitral valve disease (MVD)

The most common heart condition in dogs, particularly small breeds. The mitral valve, which separates two chambers on the left side of the heart, degenerates and starts leaking. This creates a heart murmur that your vet can hear and forces the heart to work harder to pump the same amount of blood.

Cavalier King Charles Spaniels, Dachshunds, Chihuahuas, and other small breeds are predisposed, though any dog can be affected.

Dilated cardiomyopathy (DCM)

More common in large breeds like Doberman Pinschers, Great Danes, Boxers, and Irish Wolfhounds. The heart muscle weakens and the chambers enlarge, reducing pumping efficiency. Recent concerns about diet-associated DCM (linked to certain grain-free diets) have highlighted the importance of nutrition in heart health.

Arrhythmias

Abnormal heart rhythms become more common with age. Some are benign; others compromise heart function or indicate underlying disease. Your vet may detect irregular rhythms during examination.

Common heart conditions in cats

Hypertrophic cardiomyopathy (HCM)

The most common feline heart disease. The heart muscle thickens, reducing the chamber size and making the heart stiff and less able to fill with blood. Maine Coons, Ragdolls, and British Shorthairs are predisposed, but any cat can be affected.

HCM in cats is particularly concerning because it often shows no symptoms until a crisis: sudden difficulty breathing, paralysis of the back legs from a blood clot, or sudden death.

Hyperthyroidism-related heart disease

Untreated hyperthyroidism (very common in senior cats) stresses the heart by increasing heart rate and blood pressure. The heart changes associated with hyperthyroidism are often reversible with treatment of the underlying thyroid condition.

Recognizing heart disease symptoms

Early heart disease often causes no obvious symptoms. As the condition progresses, watch for:

In dogs

• Coughing, especially at night or after exercise
• Tiring quickly during walks or play
• Rapid or labored breathing
• Restlessness, especially at night
• Decreased appetite
• Distended belly (from fluid accumulation)
• Fainting or collapse episodes
• Bluish gums (in severe cases)

In cats

Cats often hide heart disease until it's severe. Warning signs include:

• Breathing with mouth open (never normal in cats)
• Rapid breathing or panting
• Decreased activity
• Hiding more than usual
• Loss of appetite
• Sudden inability to use back legs (emergency: blood clot)
• Sudden collapse

Diagnosis

Your veterinarian may suspect heart disease based on physical examination findings like heart murmurs, irregular rhythms, or abnormal lung sounds. Diagnostic tests help confirm and characterize the condition:

Chest X-rays

Show heart size and shape, fluid in or around the lungs, and changes in blood vessels.

Echocardiogram (heart ultrasound)

The gold standard for evaluating heart structure and function. This non-invasive test visualizes the heart chambers, valves, and muscle in real-time.

Electrocardiogram (ECG)

Records the heart's electrical activity to identify arrhythmias.

Blood tests

ProBNP and cardiac troponin levels can help detect heart disease, especially when combined with other findings.

Blood pressure measurement

High blood pressure stresses the heart and can indicate or contribute to heart disease.

Treatment options

While heart disease can't usually be cured, medications and management can control symptoms and slow progression, sometimes for years.

Medications

The specific medications depend on the type of heart disease and symptoms:

• Pimobendan: Strengthens heart contraction and dilates blood vessels; a game-changer for dogs with certain heart conditions
• ACE inhibitors: Help the heart pump more efficiently by relaxing blood vessels
• Diuretics: Remove excess fluid that accumulates with heart failure
• Beta-blockers: Slow heart rate and reduce blood pressure
• Anti-arrhythmics: Control abnormal heart rhythms
• Blood thinners: Reduce clot risk, particularly important for cats with HCM

Dietary management

Sodium restriction helps manage fluid retention. Prescription cardiac diets are moderately sodium-restricted and may contain additional heart-supportive nutrients. Omega-3 fatty acids (from fish oil) may provide anti-inflammatory benefits. Avoid high-sodium treats and table food.

Activity modification

Pets with heart disease should avoid strenuous exercise but benefit from gentle, regular activity. Your vet can advise on appropriate activity levels.

Monitoring at home

Learn to count your pet's resting respiratory rate, the number of breaths per minute while sleeping. Normal is typically under 30. An increase often indicates worsening heart function and should prompt a veterinary call. Apps are available to help track this important metric.

Living with heart disease

Many pets with managed heart disease maintain good quality of life for extended periods. Regular veterinary monitoring, typically every 3-6 months, allows medication adjustments as needed.

Be prepared for possible emergencies. Know the signs of congestive heart failure (difficulty breathing, extreme fatigue, collapse) and have a plan to reach veterinary care quickly if they occur.

Prognosis

Life expectancy with heart disease varies greatly depending on the type and severity of disease, how well it responds to treatment, and whether complications develop. Some pets live for years with well-managed heart disease; others decline more rapidly.

Focus on quality of life rather than specific time predictions. As long as your pet is comfortable, enjoying food, and engaging with family, treatment is working. Discuss quality of life metrics with your veterinarian so you know what to watch for.

Prevention and early detection

While you can't always prevent heart disease, you can take steps to protect your pet's heart:

• Maintain a healthy weight to reduce cardiac workload
• Feed a balanced, appropriate diet
• Schedule regular veterinary checkups including heart auscultation
• For predisposed breeds, consider screening echocardiograms
• Treat underlying conditions like dental disease and hyperthyroidism that can affect the heart
• Know your pet's normal resting respiratory rate

Heart disease is serious but often very manageable. With proper care, many pets with heart conditions continue to enjoy life with their families for years after diagnosis.