Complete Guide to Canine Heart Disease | Symptoms, Treatment, and Home Care for Mitral Valve Disease | ブリちょく
Dogs| ✍️ BreederDirect Editorial
Complete Guide to Canine Heart Disease | Symptoms, Treatment, and Home Care for Mitral Valve Disease
A comprehensive guide to canine heart disease with a focus on myxomatous mitral valve disease (MMVD), which commonly affects small dog breeds. This article details symptoms, stage classification, treatment medications, surgical options, and home management strategies. Learn key early detection methods and daily care practices to maintain your dog's quality of life.
Key Takeaways
A comprehensive guide to canine heart disease with a focus on myxomatous mitral valve disease (MMVD), which commonly affects small dog breeds. This article details symptoms, stage classification, treatment medications, surgical options, and home management strategies. Learn key early detection methods and daily care practices to maintain your dog's quality of life.
What is Canine Heart Disease?
✍️
BreederDirect Editorial
The BreederDirect editorial team specializes in care information for animals, covering veterinary care and breeding to deliver beginner-friendly guides.
Find Dogs on BreederDirect
Buy directly from verified breeders
Browse Related Listings
Find Dogs listings related to this article on BreederDirect. Buy directly from verified breeders.
The most common heart disease in dogs is "myxomatous mitral valve disease (MMVD)," which ranks among the leading causes of death in small dog breeds. The condition has a high incidence rate in small dog breeds including Cavalier King Charles Spaniels, Chihuahuas, Maltese, Shih Tzus, and Pomeranians. Particularly after age 10, many dogs show some degree of cardiac changes.
The mitral valve, located between the left atrium and left ventricle, degenerates and thickens, causing incomplete closure and blood regurgitation. Initially asymptomatic, the disease progresses as the heart compensates by enlarging, ultimately leading to heart failure and pulmonary edema.
Stage Classification (ACVIM Guidelines)
Disease progression is classified into stages A through D according to guidelines from the American College of Veterinary Internal Medicine (ACVIM).
Stage
Status
Primary Management
A
At-risk breed (no disease development yet)
Regular auscultation and examination
B1
Heart murmur present, no cardiac enlargement, asymptomatic
Medical treatment (diuretics, ACE inhibitors, etc.)
D
Refractory heart failure
Aggressive medical treatment and hospitalization
For early detection, veterinary auscultation and thoracic radiography at least once yearly (twice yearly for high-risk breeds) are recommended.
Main Symptoms
Early Stage (B2–Early C):
- Mild cough (especially at rest or during nighttime)
- Easy fatigue and shortness of breath during exercise
- Slight decrease in appetite
Advanced Stage (Mid-C–D):
- Frequent cough and increased respiratory rate (resting respiratory rate exceeding 40 breaths per minute)
- Cyanosis (pallor or bluish tint to gums and mouth)
- Ascites (abdominal distension)
- Severe lethargy and complete loss of appetite
Critical Signs: If resting respiratory rate exceeds 40 breaths per minute or the dog is breathing with mouth open, emergency veterinary care is needed immediately.
Treatment Medications and Management
Heart disease treatment is divided into curative therapy (surgery) and medical management (drug therapy).
Primary Medications
Pimobendan (Vetmedin)
A positive inotropic agent that increases cardiac contractility and causes vasodilation. Per guidelines updated after 2019, administration is recommended starting at stage B2. Standard dosing is twice daily, preferably administered on an empty stomach (at least 1 hour after meals).
Furosemide (Diuretic)
A diuretic used to manage pulmonary edema and pleural effusion, commonly started at stage C. During treatment, increased drinking and urination occur, so fresh water should always be available.
ACE Inhibitors (Enalapril, Benazepril)
These agents reduce cardiac workload through vasodilation. Regular monitoring of renal function is necessary.
Spironolactone (Aldactone)
Used in combination with furosemide to enhance diuretic effect. As a potassium-sparing diuretic, it also helps prevent hypokalemia.
Surgical Intervention (Mitral Valve Repair)
Mitral valve repair surgery, with an increasing number of facilities performing the procedure in Japan, is most effective when performed at stage B2 to early C. Although the cost is substantial (approximately ¥1–2 million), the significant improvement in post-operative survival time and quality of life makes consideration important while the dog still has adequate strength.
Home Care Guidelines
Daily Respiratory Rate Monitoring
Record the resting respiratory rate (while sleeping) each morning and evening. Count breaths per minute and consult your veterinarian if the rate consistently exceeds 30 or increases suddenly. Smartphone apps and health tracking tools are also convenient for monitoring.
Exercise Restriction and Environmental Adjustments
Avoid vigorous exercise (running, jumping); restrict activity to gentle walks
Minimize excitement (visitors, fireworks, etc.)
Keep indoor temperature at 25°C (77°F) or below during summer to prevent heat stroke and additional cardiac strain
Minimize steps and provide ramps or platforms to reduce physical strain
Dietary Management
Restrict sodium intake to reduce strain on the heart and kidneys. Consult your veterinarian about transitioning to cardiac prescription diets (such as Royal Canin Cardiac Support or Hill's h/d). Choose low-sodium, low-fat treats and avoid overfeeding.
Emergency Response
Seek emergency veterinary care immediately, even at night or on weekends, if the following symptoms appear:
- Open-mouth breathing or labored respiration
- Inability to stand or wobbly gait
- Pale or bluish gums
- Excessive foaming or coughing up foam
Summary
While canine heart disease is difficult to cure, early detection combined with appropriate treatment and home care can maintain quality of life over an extended period. Small dog owners should make regular cardiac auscultation a routine and consistently monitor three key changes: cough patterns, respiratory rate increases, and loss of vitality. Use pill organizers or medication calendars to prevent missed doses, ensuring you can spend as much quality time as possible with your beloved companion.
