Heart Murmurs in Dogs Explained: Causes, Symptoms & Care

Dogs are renowned for their loyal and loving nature, but their hearts, like ours, are vital organs that require careful attention. Certain breeds are predisposed to heart conditions, including heart murmurs, which may be congenital (present at birth) or acquired later in life. Understanding these murmurs helps owners provide the best care and seek timely veterinary advice.

Congenital murmurs often develop during puppyhood due to defects occurring while still in the womb. These require prompt veterinary attention because they can lead to serious complications such as sudden death caused by conditions like aortic stenosis. Meanwhile, acquired heart murmurs typically develop gradually as dogs age, often linked to chronic valve disease or cardiac muscle changes.

How the Heart Functions Like a Pump

The heart is a complex pump with two sides: the right and left. The left side handles oxygen-rich blood pumped throughout the body, while the right pumps oxygen-poor blood to the lungs to receive oxygen. The left side is larger and stronger because it generates higher pressure to circulate blood further.

Inside the heart, four chambers—the left and right atria and ventricles—work together, separated by valves that prevent blood from flowing backward, ensuring efficient circulation.

The Normal Heartbeat Sound

A healthy dog's heartbeat sounds like a regular "lub-dub," caused by valves opening and closing rhythmically. In dogs with murmurs, this sound becomes turbulent or whooshing, reflecting disturbed blood flow. Vets listen at different spots on the chest to pinpoint the murmur’s cause and severity.

Understanding Acquired Heart Disorders

Acquired heart murmurs commonly stem from valve diseases, especially in small dog breeds. Endocardiosis, a thickening and degeneration of the heart valves, is prevalent and worsens over time. Despite gradual progression, many dogs compensate well initially, showing few signs.

Why Do Heart Disorders Occur More in Some Dogs?

The reasons behind valve changes remain unclear, but small breeds tend to be more susceptible. Infections traveling through the bloodstream can also inflame the heart lining, causing murmurs, frequently affecting the left heart side.

Common Causes of Heart Murmurs in Dogs

Heart murmurs arise from various issues such as:

• Congenital defects in certain breeds
• Valve degeneration, especially mitral valve disease
• Infections leading to inflammation
• Changes in blood flow dynamics or heart muscle disease

Signs of Left Side Valve Failure

When the left heart valves fail, symptoms may start mild but progress slowly. Watch for:

• Breathing difficulties during exercise
• Coughing
• Reluctance to exercise

Severe cases can be fatal, though the progression often spans years unnoticed.

Signs of Right Side Valve Failure

Failure on the right side often causes fluid accumulation in the abdomen, creating a pot-bellied appearance. Enlarged spleen or liver increases pressure on the diaphragm, leading to persistent breathlessness.

When to See a Vet

If you suspect your dog has any symptoms or belongs to a breed at risk, consult your vet promptly. Regular health checks become more crucial as dogs age to detect acquired murmurs early and begin suitable management.

Responsible Ownership and Ongoing Care

Heart murmurs signal underlying heart abnormalities that require professional assessment. Early identification and ongoing monitoring can improve quality of life. Partner closely with a reputable breeder or adopt from trusted sources, considering breeds known for healthier hearts if getting a new puppy. Always prioritise regular veterinary examinations and appropriate care.

Common Questions About Heart Murmurs in Dogs

What causes a heart murmur in dogs?

Quick Answer: Heart murmurs are caused by turbulent blood flow due to valve defects, structural heart issues, infections, or age-related valve degeneration.

Detailed Explanation: Murmurs often result from leaky or narrowed heart valves leading to abnormal blood flow. Congenital defects like holes in the heart or acquired conditions such as mitral valve disease can produce murmurs. Infections and diseases affecting heart muscle also contribute to murmur development. Each cause affects heart function differently, which impacts treatment and prognosis.

Can heart murmurs be cured in dogs?

Quick Answer: Heart murmurs themselves are signs of heart disease and usually cannot be cured but can be managed with treatment and lifestyle adjustments.

Detailed Explanation: While the murmur indicates an issue, treatment focuses on the underlying condition including medications to improve heart function, reduce symptoms, and prevent progression. Some surgical options exist for certain congenital defects. Responsible care and timely vet intervention improve outcomes and lifespan.

What signs indicate my dog has a heart murmur?

Quick Answer: Signs include coughing, exercise intolerance, breathlessness, lethargy, and occasionally a pot-bellied abdomen from fluid buildup.

Detailed Explanation: Early stages may show no signs, but as heart function declines, symptoms like coughing during activity, reluctance to play or walk, difficulty breathing, and swelling from fluid accumulation can appear. Not all murmurs cause symptoms, making veterinary checks important for detection.

How do vets diagnose heart murmurs in dogs?

Quick Answer: Using a stethoscope during a physical exam, vets listen for abnormal heart sounds and may conduct further tests like echocardiography or X-rays.

Detailed Explanation: Auscultation reveals the murmur's presence, timing, and location. Diagnostics such as echocardiograms help assess valve function and heart size, while X-rays show fluid accumulation. Blood tests can evaluate other contributing health issues. These combined data guide treatment plans.

Conclusion

Heart murmurs in dogs are important indicators of possible heart disease. While some murmurs may be harmless, many result from serious congenital or acquired conditions requiring veterinary care. Early detection, proper diagnosis, and treatment improve the quality and length of life for affected dogs. Responsible ownership involves regular health checks, awareness of symptoms, and consulting your vet if concerned. Caring for a dog’s heart is key to keeping your loyal companion happy and healthy throughout their life.