Panting accompanied by a heart murmur in dogs can signal a variety of underlying health issues, some of which may be serious.
While panting is often a normal response to heat, exercise, or excitement, when it occurs alongside an irregular or abnormal heart sound, it may indicate a problem with the heart or circulation.
We outline the common causes of panting and a heart murmur in dogs, what you can do, and when to seek veterinary help.
Dog Panting and Heart Murmur — Why It Happens
When a dog is panting and has a heart murmur, it usually indicates that the heart is struggling to pump blood efficiently. A murmur is a sign of turbulent blood flow, often caused by valve disease, congenital defects, or heart failure. As the heart works harder to circulate oxygen, the dog may pant excessively to compensate for reduced oxygen levels in the blood.
This increased effort can also cause fatigue, coughing, or restlessness, especially after activity or at night. In more advanced cases, fluid may build up in the lungs or abdomen, making breathing even more difficult.
Panting in a dog with a heart murmur should always be taken seriously, as it may signal worsening cardiac function that requires prompt veterinary evaluation and treatment.
Dog Panting and Heart Murmur: Common Causes
Congenital Heart Defects
Some dogs are born with structural heart problems that can cause murmurs and excessive panting.
Common congenital defects include patent ductus arteriosus (PDA), pulmonic stenosis, or ventricular septal defects.
These abnormalities can lead to inefficient blood flow, reducing oxygen delivery to tissues and prompting panting as the body attempts to compensate.
Signs of congenital heart defects may appear early in puppies, such as difficulty exercising, coughing, or failure to gain weight properly.
Early diagnosis is crucial, and surgical or medical intervention may be necessary depending on the defect and its severity.
Read more: Dog Panting and Heart Beating Fast (Understanding the causes and care)
Acquired Heart Disease
Heart murmurs in older dogs often develop due to acquired heart conditions. Mitral valve disease and dilated cardiomyopathy are common causes, particularly in small and large breed dogs respectively.
As the heart’s ability to pump efficiently decreases, the body responds with faster breathing and panting to maintain oxygenation.
Additional signs may include coughing, exercise intolerance, fatigue, and fluid accumulation in the lungs or abdomen.
Regular veterinary check-ups can detect early murmurs, allowing timely monitoring and treatment to slow disease progression.
Heart Failure
Heart failure is a serious condition in which the heart cannot meet the body’s demands.
Dogs with heart failure often pant more than usual, even at rest, and may display a noticeable heart murmur due to turbulent blood flow.
The heart races in an attempt to compensate for reduced efficiency, leading to increased respiratory effort.
Other symptoms can include coughing, restlessness, difficulty lying down comfortably, swelling in the limbs or abdomen, and fainting in severe cases.
Heart failure requires veterinary management and sometimes hospitalization, depending on severity.
Anemia
Severe anemia can cause panting and exacerbate the effects of a heart murmur. When red blood cell levels are low, the blood cannot carry enough oxygen, prompting the heart to beat faster and the dog to pant more heavily. This often occurs alongside pale gums, lethargy, and weakness.
Causes of anemia include chronic disease, blood loss, parasites like fleas or ticks, or autoimmune conditions.
Treatment depends on identifying the underlying cause and may involve medications, blood transfusions, or dietary adjustments.
Respiratory Disease
Respiratory problems can amplify the signs of a heart murmur. Conditions like pneumonia, chronic bronchitis, or collapsing trachea reduce oxygen intake, causing the dog’s heart to work harder.
Panting increases to compensate for reduced oxygen, and the murmur may become more noticeable during stress or exertion.
Signs may include coughing, wheezing, labored breathing, and intolerance to exercise. Prompt veterinary assessment is crucial to determine whether the respiratory or cardiac problem requires immediate treatment.
Fever or Infection
Systemic infections can cause elevated heart rate and panting, intensifying the effects of a heart murmur.
As the body fights infection, the heart works harder to deliver oxygen and nutrients, and breathing accelerates to meet increased metabolic demands.
Other signs may include lethargy, vomiting, diarrhea, loss of appetite, or swollen lymph nodes. Infections can complicate existing heart conditions, so early veterinary evaluation is essential.
What to Do If Your Dog Is Panting and Has a Heart Murmur
Monitor your dog closely. Note the intensity, duration, and circumstances of panting, as well as any additional signs like coughing, exercise intolerance, or lethargy. This information will be valuable for your veterinarian.
Maintain a calm environment. Reduce stressors such as loud noises or excessive activity, and provide a comfortable resting space. Minimizing stress helps prevent unnecessary strain on the heart.
Ensure access to fresh water and moderate temperature. Keep your dog hydrated and avoid exposure to heat, which can worsen panting and put additional stress on the heart.
Limit strenuous exercise. Dogs with heart murmurs may tolerate activity poorly, so short, gentle walks are preferable to high-intensity exercise. Overexertion can trigger dangerous increases in heart rate and respiratory effort.
Follow veterinary recommendations. Your veterinarian may prescribe medications, dietary adjustments, or monitoring strategies to manage the heart murmur and associated symptoms. Administering medications consistently and reporting changes promptly is essential.
When to Call or Visit Your Vet
Immediate veterinary attention is necessary if your dog shows any of the following:
Persistent panting at rest, especially if accompanied by rapid or irregular heartbeat.
Labored or noisy breathing, coughing, or wheezing.
Collapse, fainting, or extreme weakness.
Pale, blue, or gray gums, indicating poor oxygenation.
Signs of fluid accumulation in the abdomen, chest, or limbs.
Puppies or senior dogs with new or worsening symptoms.
Prompt evaluation is crucial to detect worsening heart disease, heart failure, or complications from secondary conditions like anemia or infection.
Read more: Dog Panting and Hot Ears (Is it just heat or something more?)
Key Takeaway
Panting paired with a heart murmur in dogs can indicate congenital defects, acquired heart disease, heart failure, anemia, respiratory issues, or systemic infection.
Careful observation, creating a calm environment, and limiting exertion are key first steps.
Because heart murmurs can signal serious underlying problems, any persistent or severe symptoms warrant veterinary evaluation.
Acting quickly helps protect your dog from complications and ensures the best possible quality of life.
Regular check-ups, monitoring for subtle changes, and prompt intervention when needed can make a significant difference for dogs with heart murmurs.