Heart Disease in Dogs: Types, Symptoms, Diagnosis, and Treatment

Heart disease in dogs is a set of conditions affecting the heart. The dog heart has four main components, the heart muscle, valves, pericardium, and electrical conducting system, and each is susceptible to diseases. 

The most common heart problem types in dogs include heartworm, heart valve disease, arrhythmias, congestive heart failure, pericardial disease, myocardial disease, stenosis, and shunts. 

Persistent cough, difficulty breathing, excessive panting, syncope, exercise intolerance, ascites, back leg weakness, and behavioral changes are standard heart failure symptoms in dogs. Dog heart failure back legs is sudden weakness or paralysis in dogs with advanced heart conditions. 

Electrocardiogram (ECG) and echocardiogram are the golden standard for diagnosing heart issues. 

The treatment for heart disease in dogs is individually tailored and includes medications, open heart surgery, pacemakers, dietary modifications, and limited exercise.  

What is Heart Disease in Dogs?

Heart disease in dogs is an umbrella term that includes various types of heart conditions, whether congenital or acquired. Certain dog breeds are predisposed to heart diseases. 

The heart pumps oxygenated (oxygen-rich) blood to the different organs in the body for nourishment and deoxygenated (oxygen-free) blood to the lungs for “cleaning” or oxygenation. 

Eight million dogs, or 10% of all dogs in the USA, suffer from heart disease, with 75% of senior dogs having some form of heart condition, according to a post on “Heart Disease in Dogs” published by CVCAVets in 2024. 

Diseases of the heart impair its pumping ability, which is fatal. Heart problems in dogs require urgent veterinary attention. 

What part of a Dog's Heart is prone to Heart Disease?

All parts of a dog's heart are prone to heart disease. The heart has four functional components, including muscle, valves, pericardium, and an electrical conducting system. 

The heart muscle pumps blood through the body. The valves prevent blood from flowing in the wrong direction. The pericardium surrounds and protects the heart. The electrical conducting system produces and transports impulses that control the function of the dogs heart. 

Knowing the basic heart anatomy in dogs is critical for understanding the different conditions affecting the heart's main parts.

Can Dogs Have Heart Attacks?

Yes, dogs can have heart attacks. Heart attacks in dogs are rare but possible. Blockage or leakage of the coronary arteries, resulting in loss of blood flow to the heart muscle, is the most common cause. 

Heart attacks in dogs manifest with difficulty breathing and collapse. The attacks are fatal in some cases. Contact the veterinarian immediately if suspecting a heart attack.

What are the Different Types of Heart Diseases in Dogs?

The different types of heart disease in dogs are listed below. 

• Heartworm Disease: Heartworm disease is a life-threatening heart and lung condition caused by the parasitic worm Dirofilaria immitis, which spreads through mosquito bites. 
• Heart Valve Disease: Heart valve disease is a progressive degeneration of the mitral valves, causing mitral regurgitation. The issue is common in small to medium breeds. 
• Arrhythmias: An umbrella term for abnormalities in the dog’s heart rhythm, which include altered speed, strength, or regularity of heartbeats. 
• Congestive Heart Failure: Congestive heart failure is a fatal problem when the heart is unable to pump blood efficiently through the dog’s body. 
• Pericardial Disease: Pericardial disease or effusion is the accumulation of fluid in the sac around the heart that prevents regular blood flow. 
• Myocardial Disease: Myocardial disease is a degenerative condition in which the heart enlarges, and its muscle walls get thinner and weaker, making it unable to pump blood. 
• Stenosis: Aortic stenosis is a congenital defect in large-breed dogs in which the aortic valve is narrow and causes a loud ejection murmur. 
• Shunts: Congenital heart defects in which blood flows in abnormal directions. The most common shunt in dogs is caused by a patent ductus arteriosus (PDA).  

1. Heartworm Disease

Heartworm disease is a parasitic condition caused by the worm Dirofilaria immitis. Dogs acquire the worm through bites from infected mosquitoes. 

The worms complete their life cycle in the dog and inhabit the heart and pulmonary vessels. Adult worms are over one foot long and eventually clog the heart, block its pumping ability, and cause congestive heart failure. 

Dogs with heartworm disease are exercise intolerant, lethargic, cough, pant excessively, have difficulty breathing, and faint. The treatment includes antiparasitic medications, heartworm preventatives, and antibiotics.  

2. Heart Valve Disease

Heart valve disease is a degenerative alteration of the valves. The most common heart valve condition is mitral valve disease (MVD), in which the mitral valves thicken and do not close properly. 

The lack of closure causes leaking, known as mitral regurgitation. Long-term regurgitation leads to heart enlargement, arrhythmias, and congestive heart failure. 

MVD is common in small to medium-sized breeds, particularly in Cavalier King Charles Spaniels and Dachshunds. Heart valve disease is treated medically or surgically, based on the severity. 

3. Arrhythmias

Arrhythmia is an abnormal heart rhythm manifesting with changes in the heartbeat’s speed, strength, or regularity. Bulldogs, Pugs, Boxers, Pekingese, and other brachycephalic dog breeds are predisposed to arrhythmias. 

Causes of arrhythmias in dogs include birth defects, injuries, infections, stress, heart disease, and toxin exposure. Arrhythmias manifest with weakness, coughing, exercise intolerance, pale gums, and fainting episodes. 

The treatment for arrhythmias in dogs is individually tailored based on the underlying cause and the dog’s needs. 

4. Congestive Heart Failure

Congestive heart failure (CHF) is when the heart is unable to pump blood efficiently, causing fluid to leak into the lungs and other major organs. CHF is a side effect of various heart diseases. 

Dogs develop left or right-sided congestive heart failure. Left-sided heart failure is when fluid accumulates in the lungs, causing pulmonary edema. Right-sided failure occurs when fluid builds up in the extremities (peripheral edema) or abdomen (ascites). 

Treating congestive heart failure includes treating the fluid buildup and the underlying cause. Tailored nutrition is recommended for the long-term management of dogs with CHF. 

5. Pericardial Disease

Pericardial disease, or pericardial effusion, is an abnormal fluid accumulation in the sac surrounding the heart called the pericardium. The fluid pressures the heart and lowers its pumping abilities (cardiac tamponade). 

Bulldogs, Boxers, Retrievers, Great Danes, German Shepherds, and Saint Bernards are prone to pericardial effusion. Tumors, infections, clotting disorders, and toxins increase the risk of pericardial disease in dogs. 

Pericardiocentesis or draining the accumulated fluid solves the cardiac tamponade. Managing the underlying cause treats pericardial disease in the long run. 

6. Myocardial Disease

Myocardial disease in dogs is an umbrella term that includes conditions affecting the heart muscle. The most common myocardial disease in dogs is dilated cardiomyopathy or DCM. 

Dilated cardiomyopathy is prevalent in large breeds (Doberman Pinschers, Irish Wolfhounds, Boxers, Saint Bernards, and Newfoundlands) and rare in specific small breeds (English Springer Spaniels, Cocker Spaniels, and Portuguese Water Dogs). 

The widespread use of grain-free diets is associated with the development of DCM in dogs. Dogs with dilated cardiomyopathy are managed with medications and special diets. 

7. Stenosis

Aortic stenosis is the narrowing of the dog’s aortic valve. The aortic valve controls blood flow from the heart's left lower chamber to the aorta. 

Aortic stenosis is hereditary in large-breed dogs such as German Shepherds, Newfoundlands, Rottweilers, Boxers, and Golden Retrievers. Dogs occasionally acquire stenosis after bacterial inflammation of the heart’s inner layer. 

The narrowing adds pressure to the heart, which increases in size and thickness to compensate for the reduced pumping efficiency. Open heart surgery is a treatment option with a high mortality rate. 

8. Shunts

Shunts are irregular blood flow directions. A common heart shunt is patent ductus arteriosus or PDA. Puppies in the womb have the aorta connected to the pulmonary artery through a blood vessel called ductus arteriosus. 

The vessel is supposed to close at birth but remains open in some dogs post-birth. PDA is the condition in which the ductus arteriosus remains open. 

There are left-to-right shunting PDAs and right-to-left shunting PDAs based on the blood flow direction. The prognosis for dogs with patent ductus arteriosus is guarded to poor. 

What are the Symptoms of Heart Disease in Dogs?

The symptoms of heart disease in dogs are listed below. 

• Persistent Cough: A persistent cough that is more intense after exercise and before going to bed is a telltale sign of heart conditions in dogs. 
• Difficulty Breathing: Trouble breathing is standard and manifests with keeping the legs wide and the neck stretched out to grasp for air.
• Excessive Panting: Dogs with heart problems pant excessively during minor physical activities or, in severe cases, even when resting. 
• Fainting or Collapse: Heart diseases compromise blood flow into the dog’s brain, and when the brain suffers oxygen deprivation, it causes syncope or loss of consciousness. 
• Exercise Intolerance: Dogs with heart problems tire easily and lack stamina, which makes them intolerant to regular exercise regimens. 
• Abdominal Swelling: Fluid accumulates in the abdominal cavity of dogs with heart problems, resulting in abdominal swelling or ascites. 
• Back Leg Weakness: Dog heart failure back legs refers to the unprovoked and sudden onset of weakness or paralysis in the dog’s hind limbs. 
• Behavioral Changes: Behavioral heart disease symptoms in dogs include loss of appetite, withdrawal, and lethargy. 

What is the most common sign of Heart Failure in Dogs?

The most common sign of heart failure in dogs is difficulty breathing. The medical term for troubled breathing is dyspnea. Dogs with CHF breathe fast and forcefully. 

Some dogs keep their legs wide apart and their necks stretched to grasp air more easily, or they are unable to sit at all and remain in a standing position for long. 

Other common signs of heart failure in dogs include increased resting respiratory rate, exercise intolerance, extreme fatigue, persistent coughing, fainting or collapsing, and loss of appetite.

How does Heart Disease in Dogs Diagnosed?

Heart disease in dogs is diagnosed with a physical exam, electrocardiogram (ECG), and echocardiogram. The veterinarian starts with the standard physical exam while monitoring the dog's heart and measuring blood pressure. 

Electrocardiogram (ECG) measures the heart's electrical activity to check for abnormal heart rhythms. Echocardiography uses an ultrasound to examine the heart in more detail. 

The vet performs diagnostic analyses such as complete blood count, biochemistry panels, serology tests, and urinalysis to evaluate the dog's health based on the initial findings.

How long can Dogs live with Heart Disease?

Dogs with heart disease live 6 months to 1.5 or 2 years. The exact duration depends on the type of heart condition and its progression. 

Minor heart murmurs are manageable and do not significantly impact the dog’s longevity. More severe problems, like heartworms, require lifelong treatment. Advanced diseases like heart failure entail treatments and supportive care to maintain quality of life. 

How fast does Heart Failure progress in Dogs?

Heart failure progresses in dogs quickly. Dogs with congestive heart failure die within six months to two years after diagnosis. Congestive heart failure progresses through five stages, graded A, B, B2, C, and D.

Stage A dogs are predisposed dog breeds (Terriers, Poodles, and Cocker Spaniels) that lack heart failure symptoms and do not have structural heart changes. 

Stage B dogs have a swishing or whooshing-sounding heart murmur that is audible on examination but does not indicate disease. Stage B1 dogs have no apparent heart failure symptoms but visible structural heart changes on X-ray and echocardiogram. 

Stage C dogs have structural changes to the heart and show heart failure symptoms but respond well to treatment. 

Stage D is known as end-stage and includes dogs with advanced structural heart damage and severe heart failure symptoms that do not respond to treatment.

Is a Dog in Pain with Heart Failure?

No, a dog is not in pain with heart failure. Dogs diagnosed with congestive heart failure (CHF) do not display signs indicative of pain. 

Humans with CHF complain of occasional chest pain. Dogs are unable to identify chest pain and are more tolerant of pain specifically. Pets are instinctually driven to hide signs of discomfort as a defense mechanism.

Can Dogs Die with Heart Disease?

Yes, dogs can die with heart disease. Heart problems in dogs are congenital or develop later in life, and some progress slowly while others advance quickly. 

The most common congenital heart disease in dogs is patent ductus arteriosus (PDA). The most frequently diagnosed acquired heart condition in dogs is degenerative valve disease (DMVD). Dogs with PDA and DMVD die unless promptly treated.

What Dog Breeds Are Prone to Heart Disease?

Dog breeds prone to heart disease include Cavalier King Charles Spaniels, Dachshunds, Miniature and Toy Poodles, Doberman Pinschers, Boxers, Golden Retrievers, and Miniature Schnauzers. 

Different breeds are predisposed to specific heart conditions. Dilated cardiomyopathy occurs in large breeds such as Great Danes, Irish Wolfhounds, Doberman Pinschers, and Saint Bernards. 

Mitral valve disease is prevalent in small breeds, like Cavalier King Charles Spaniels, Maltese, Shih Tzus, Chihuahuas, and Miniature Poodles or Schnauzers. 

Dog heart failure symptoms are typical in Spaniels, Boxers, Dachshunds, Dobermans, and Poodles. 

What are the Treatments for Heart Disease in Dogs?

The treatments for heart disease in dogs are listed below. 

• ACE Inhibitors: ACE inhibitors, such as enalapril, benazepril, and captopril, reduce blood pressure and volume, easing stress and pressure on the heart. 
• Pimobendan: Pimobendan strengthens heart contractions, lowers blood vessel pressure, and is prescribed for dogs with heart failure. 
• Pacemakers: Pacemakers are small, two-part devices that promote normal heartbeat patterns in dogs suffering from arrhythmias. 
• Open-Heart Surgery: Open-heart surgery is recommended in dogs with congenital heart defects and acquired valve diseases. Open-heart surgeries are risky and costly. 
• Diet Modification: Dogs with heart problems require low-sodium diets rich in vitamins B and E, taurine, carnitine, coenzyme Q10, and antioxidants. 
• Exercise Restriction: Limited physical activity is recommended to keep dogs with heart disease in a healthy weight range without causing excessive heart strain. 

How can CBD Products help treat Heart Disease in Dogs?

CBD products can help treat heart disease in dogs naturally. CBD, or cannabidiol, is a hemp extract that works through the endocannabinoid system (ECS).

Cannabidiol reduces inflammation, promotes calmness, relieves pain, increases appetite, and supports sleep. The combination of effects is beneficial for managing the common symptoms of heart disease in dogs. 

CBD alone is not a heart condition cure but makes an excellent addition to the treatment plan. Consult the vet to ensure safe use, minimize side effects, and ask for help choosing the best CBD oil product for the dog’s heart disease. 

How Much Does it Cost to Treat Heart Disease in Dogs?

It costs 3,000 to 10,000 dollars on average to treat heart disease in dogs, including bloodwork, x-rays, medication, surgical expertise, and aftercare treatments. The costs add up quickly depending on the severity of the dog’s individual condition. 

Bloodwork and X-rays to diagnose and monitor heart conditions cost between $500 and $1,000 annually. Prescription food for heart issues costs around $85 for a 17-pound bag. Monthly medications, depending on the type, cost between $50 and $150. 

Heartworm treatment costs $500 to $1,000, while open heart surgery costs over $10,000. Hospitalization and stabilization of a dog with a heart problem range from $1,000 to $3,000. 

Can Dogs with Heart Disease be treated at home?

No, dogs with heart disease cannot be treated at home. Heart disease is a potentially fatal condition and requires professional veterinary care and treatment. 

Certain home remedies and mainstream treatments help manage dogs with heart disease. Popular options include fish oil, coenzyme Q, antioxidants, and hawthorn. Consult the vet before using a home remedy for a dog with heart disease.

Is it possible to prevent Heart Disease in Dogs?

No, it is not possible to prevent heart disease in dogs. Many types of heart disease in dogs are congenital. Specific measures help reduce the risk of heart problems in dogs. 

Feed a healthy and nutritionally balanced diet suitable for the dog's age, breed, and lifestyle. Practice daily physical activity and maintain the dog's body weight within the normal limits.

What is the Prognosis of Heart Disease in Dogs?

The prognosis of dogs with heart disease is guarded. The life expectancy depends on the type of heart disease, its progression, and the dog's age, overall health, and response to treatment. 

The outcome is good for dogs with early caught and promptly treated heart disease. Dogs with congestive heart failure, in most cases, live for 6 months to 1.5 or 2 years after the diagnosis. 

End-of-life care and euthanasia are worth considering in dogs with end-stage heart failure who do not respond to treatment and are suffering.