What Is Pulmonary Stenosis in Dogs?
Pulmonary stenosis in dogs is a congenital heart defect characterized by the narrowing of the valve situated between the right ventricle and the pulmonary artery. This narrowing occurs due to thickening of the valve leaflets and possible partial fusion. The condition is present at birth and is likely influenced by genetic and hereditary factors.
Pulmonary stenosis causes increased pressure in the right side of the heart, leading to thickening of the heart muscle, heart failure, arrhythmias, and potentially sudden death. Puppies with pulmonary stenosis often have additional congenital heart defects such as aortic stenosis and ventricular septal defect.
Symptoms
Symptoms of pulmonic stenosis in dogs vary depending on the severity of the narrowing. In cases of mild narrowing, some dogs may not exhibit any clinical signs and remain asymptomatic throughout their lives.
However, dogs with more severe narrowing may experience the following symptoms due to the rapid and turbulent blood flow and thickening of the right ventricle:
- Murmur (ranging from mild to severe)
- Exercise intolerance
- Fainting (syncope) or collapse
- Arrhythmias
- Right-sided congestive heart failure (CHF)
- Ascites (fluid buildup)
Causes
The cause of pulmonary stenosis in dogs is congenital, meaning they are born with the defect. There may be an inherited component in certain breeds. The breeds most commonly affected by this condition include:
- English and French Bulldogs
- Terriers (Jack Russell Terriers)
- Labrador Retrievers
- Miniature Schnauzers
- American Cocker Spaniels
- Samoyeds
- Keeshonden
- Mastiffs
- Beagles
Diagnosis
Veterinarians typically diagnose pulmonary stenosis in dogs during routine puppy examinations, often through the identification of a heart murmur, arrhythmia (irregular heartbeat), or signs of heart failure such as fluid accumulation.
A heart murmur is detected by listening to the heart and lungs using a stethoscope. It signifies turbulence in blood flow, although it does not exclusively indicate pulmonary stenosis as there are other potential causes of blood turbulence. Upon detecting a murmur, veterinarians may conduct further diagnostic tests, including:
- Radiographs
- Electrocardiography (ECG)
- Echocardiography
Treatment
The preferred treatment for pulmonic stenosis in dogs is cardiac catheterization using balloon valvuloplasty. This minimally invasive procedure aims to open the narrowed heart valve and is typically performed at specialized veterinary cardiology referral centers.
During balloon valvuloplasty, a catheter with a balloon is threaded into the heart and then inflated to dilate the narrowed pulmonic valve, thereby improving blood flow. While there is no cure for pulmonic stenosis, balloon valvuloplasty can effectively manage and enhance the condition.
Additionally, some dogs may receive treatment with beta blockers, such as atenolol, to further manage the condition.
Living and Management
The prognosis for dogs with pulmonary stenosis depends largely on the severity of the obstructions. Those with mild or moderate stenosis may not require treatment and can live a normal lifespan. Dogs with moderate stenosis typically require balloon dilation and may exhibit symptoms like exercise intolerance and fainting.
In severe cases, some dogs may require lifelong medication even after treatment. It’s crucial to impose moderate exercise restrictions. It’s essential to follow all instructions provided by your veterinarian and veterinary cardiologist.
Pulmonary Stenosis in Dogs FAQS
Is it OK to breed a dog with a mild case of pulmonary stenosis?
Breeding is typically not recommended due to the potential hereditary component of the condition.
What is the life expectancy of a dog diagnosed with pulmonary stenosis?
The prognosis varies depending on the severity of the condition. Dogs with right-sided congestive heart failure or irregular heartbeats like atrial fibrillation may have a guarded to poor prognosis. However, dogs with mild or moderate stenosis may live normal lives without treatment, while others may require treatment and/or beta blockers.