Mitral Valve Disease (MVD) in Dogs: Symptoms, Treatment & Prognosis

What Is Mitral Valve Disease?

Mitral valve disease (MVD) is the most common heart condition in dogs. It occurs when the mitral valve—the valve between the left atrium and left ventricle—degenerates and fails to close properly, allowing blood to leak backward (regurgitation).

The condition is progressive and typically develops in small-breed dogs as they age. Early detection and appropriate management can slow progression and improve quality of life.

Symptoms of Mitral Valve Disease in Dogs

Early Signs

• Heart murmur detected during routine vet exams (often no obvious symptoms yet)
• Mild exercise intolerance — tiring sooner on walks
• Occasional cough, especially at night or when resting
• Rapid breathing when excited or active

Progressive Symptoms

• Persistent cough that worsens over time
• Labored breathing or panting with minimal exertion
• Lethargy and reduced interest in activity
• Reduced appetite or weight loss
• Restlessness at night, difficulty settling
• Fainting spells (syncope) — rare but possible

Emergency Signs

• Severe difficulty breathing — gasping, extended neck, obvious distress
• Collapse or sudden weakness
• Pale or blue gums
• Abdomen swollen with fluid (ascites)
• Inability to rest — constant panting or standing

What Causes Mitral Valve Disease in Dogs?

MVD is primarily a degenerative condition related to aging:

• Valve degeneration — the valve leaflets thicken and become leaky over time
• Genetic predisposition — strong breed association (see below)
• Age — most commonly seen in dogs 8 years and older
• Chronic stress on the valve — years of normal wear may contribute
• Myxomatous degeneration — the most common pathologic change

Breeds Most at Risk

MVD is strongly associated with small and toy breeds:

• Cavalier King Charles Spaniels — highest risk; often develops earlier (5–6 years)
• Dachshunds
• Miniature Poodles
• Chihuahuas
• Cocker Spaniels
• Miniature Schnauzers
• Maltese
• Boston Terriers
• Pomeranians

How Mitral Valve Disease Is Diagnosed

Your veterinarian will use several tools to diagnose MVD:

1. Physical examination — detecting a heart murmur (typically left-sided)
2. Echocardiography (cardiac ultrasound) — confirms valve changes, assesses severity
3. Chest X-rays — evaluates heart size and lung congestion
4. Blood work — including NT-proBNP to assess heart strain
5. Electrocardiogram (ECG) — if arrhythmias are suspected
6. Blood pressure measurement — to guide treatment

Treatment Options

Medical Management

• Pimobendan — improves heart function and is often started when heart enlargement is detected
• ACE inhibitors (e.g., enalapril) — help reduce fluid retention and ease workload on the heart
• Diuretics (e.g., furosemide) — remove excess fluid when congestive heart failure develops
• Beta-blockers or calcium channel blockers — may be used for specific arrhythmias
• Sildenafil — if pulmonary hypertension is present

Surgical Options

• Mitral valve repair or replacement — available at some specialty centers but not widely performed; very expensive and complex
• Percutaneous options — some investigational techniques are emerging

Alternative/Supportive Therapies

• Omega-3 fatty acids — may support heart health (discuss dosage with your vet)
• Taurine supplementation — if deficiencies are identified
• Low-sodium diet — often recommended in heart failure
• Acupuncture or physical therapy — for comfort; not a substitute for medication
• Stress reduction — calm environment, avoid extreme heat or overexertion

At-Home Care

• Strict medication schedule — give medications at the same times each day
• Monitor respiratory rate at rest — track and report increases to your vet
• Weight monitoring — sudden gain may indicate fluid retention
• Limit intense exercise — short, gentle walks are usually fine
• Cool, quiet resting area — help your dog avoid overheating
• Regular vet checkups — every 3–6 months or as recommended

Prognosis & Life Expectancy

• Early stages (murmur only) — dogs often live years with minimal impact
• Once congestive heart failure develops — median survival is typically 6–18 months with treatment, though some live longer
• Factors that improve prognosis — early detection, consistent medication, good owner compliance, and breed (e.g., Cavaliers may progress differently than other breeds)

Prevention

• Annual wellness exams — especially for at-risk breeds after age 5
• Breeding screening — echocardiograms for breeding dogs in high-risk breeds
• Maintain healthy weight — obesity adds strain on the heart
• Avoid breeding affected dogs — to reduce genetic transmission
• Early treatment — starting medication at the right time can slow progression

Cost of Treatment

• Diagnosis — $200–$600 (exam, X-rays, echocardiogram, blood work)
• Monthly medications — $50–$150 depending on drugs and dosage
• Follow-up visits — $50–$150 every 3–6 months
• Emergency care — $500–$2,000+ if hospitalization is needed
• Surgical repair — $15,000–$30,000+ (if pursued at specialty center)

Frequently Asked Questions