강아지 동맥관 개존증(PDA) 자주 묻는 질문 Q&A — 보호자가 꼭 알아야 할 핵심

What is Patent Ductus Arteriosus (PDA) in Puppies? — Treatment and Surgical Timing

HeartQ&AMeongsiljang Veterinary Advisory Board

Patent ductus arteriosus (PDA) in puppies is a congenital heart defect in which the ductus arteriosus, a blood vessel that should close at birth, remains open, placing extra strain on the heart. Early detection and treatment are essential.

What is Patent Ductus Arteriosus (PDA) in Puppies?

An anatomical image showing a patent ductus arteriosus in a puppy's heart.

Patent ductus arteriosus (PDA) in dogs is a congenital heart defect in which the ductus arteriosus, a blood vessel that should remain open during fetal development, fails to close naturally after birth, resulting in abnormal blood flow within the heart. In this left-to-right shunt, high-pressure blood from the aorta leaks into the pulmonary artery, forcing the heart to work harder and placing a continuous strain on it. If left untreated, this can lead to an enlarged heart and left-sided heart failure. While PDA is seen in some small breeds, it also occurs in large breeds such as Doberman Pinschers and German Shepherds, and is known to be approximately three times more common in females than in males. Early detection through regular check-ups is important even in the absence of symptoms, and prognosis is generally favorable with timely treatment.

Why Does the Ductus Arteriosus Fail to Close?

Before birth, puppies receive oxygen through the placenta, so the ductus arteriosus must remain open. However, after birth, when the lungs begin functioning and oxygen levels rise, the ductus arteriosus should naturally close. Patent ductus arteriosus (PDA) occurs when this process fails, leaving the ductus arteriosus open. While the exact cause is not fully understood, genetic factors or abnormal fetal development may play a role. Certain breeds show a clear genetic predisposition. Early diagnosis and management significantly improve treatment success rates.

Comparison of a normal puppy heart and one with patent ductus arteriosus

What Are the Main Symptoms of PDA?

A hallmark physical exam finding in puppies with patent ductus arteriosus (PDA) is a continuous heart murmur caused by a left-to-right shunt. This murmur is typically best heard at the left cranial chest wall (the base of the heart) or along the dorsal aspect, and in left-to-right shunting PDA, it characteristically presents as an unbroken, continuous sound. Other clinical signs may include exercise intolerance, easy fatigability, coughing, or difficulty breathing. In some cases, sudden collapse resembling syncope may be observed. Although symptoms may appear mild in the early stages, the strain on the heart increases over time, making early detection crucial for effective treatment.

An image showing a dog listening to its heartbeat and the waveform of that sound

Signs Requiring Immediate Veterinary Attention

If your dog is breathing heavily, struggling to catch its breath even after mild exercise, has a bluish tint to its mouth, or suddenly collapses, this is a medical emergency. These signs indicate severe heart dysfunction and require immediate veterinary attention.

How Is PDA Diagnosed?

The veterinarian listens to the puppy’s heart sounds with a stethoscope to identify characteristic heart murmurs. In a left-to-right shunt patent ductus arteriosus (PDA), a continuous murmur that does not interrupt is heard, most clearly at the left cranial chest (over the heart base) or along the back. An echocardiogram then precisely evaluates the diameter of the ductus arteriosus, blood flow direction, and cardiac structure, while color Doppler imaging confirms turbulent blood flow within the pulmonary artery. Thoracic radiographs help assess heart size and the condition of the pulmonary vessels. Diagnosis is made by comprehensively analyzing these test results, and early diagnosis improves treatment success rates.

An image of a veterinarian performing an echocardiogram on a dog

What Are the Treatment Options?

PDA can usually be completely cured with surgery or catheter-based treatment. Surgery involves tying off or cutting the ductus arteriosus, providing long-term stability. Catheter treatment involves inserting a special device through a blood vessel to block the ductus arteriosus. This method allows for quick recovery and leaves minimal scarring. Both methods have high success rates, and early treatment leads to faster recovery. Consult with your veterinarian to choose the most suitable treatment option.

A scene of a puppy undergoing surgery to tie off the ductus arteriosus

Surgery vs. Catheter Treatment Comparison

Item	Surgical Treatment	Catheter Treatment
Recovery Time	1–2 weeks	1–3 days
Pain Level	Moderate	Low
Cost	Approx. $600	Approx. $900
Suitability	All breeds	Dogs above a certain size

Catheter treatment offers faster recovery but has size limitations and higher costs. Surgery can be applied universally.

Points to Note: Treatment Timing and Breeds

Early detection and treatment of patent ductus arteriosus (PDA) are crucial. If the abnormal blood flow is corrected before it places excessive strain on the heart, the enlarged heart can often shrink back to normal size, allowing for a good recovery. Particular care should be taken with early screening and selecting the appropriate timing and method of treatment for breeds prone to PDA, such as Chihuahuas, Cocker Spaniels, and Poodles, as well as for female dogs.

Reviewed by a veterinarian

Dr. Tony — Punnawat Phongkittirak

Veterinarian

A veterinarian who majored in veterinary medicine at Khon Kaen University, Thailand, and completed the IVSA program at North Carolina State University in the United States. Drawing on clinical experience at animal hospitals, he works in the pet healthcare field and is dedicated to building a digital care environment that connects pet parents with veterinarians.

Frequently Asked Questions

Can PDA be genetic?

Yes, a genetic predisposition has been reported in several breeds. Chihuahuas, Cocker Spaniels, Poodles, Collies, and German Shepherds are known to be particularly susceptible. The condition occurs not only in small-breed dogs but also in large breeds, and it is approximately three times more common in females than in males.

Can it come back after treatment?

Relapse after treatment is very rare. However, since some residual blood flow may remain immediately after the obstruction is relieved, it's a good idea to have regular heart check-ups to monitor for any abnormalities.

Does a heart murmur in a puppy always mean PDA?

No. Heart murmurs can have various causes. However, the continuous murmur heard in a left-to-right shunt patent ductus arteriosus (PDA) is characteristic, so if a heart murmur is detected, diagnostic testing to determine whether PDA is present is absolutely necessary.

If my pet has PDA, can they still go for walks?

Before treatment, it's important to avoid excessive exercise. After treatment, normal walks are possible. Please start slowly and follow your veterinarian's instructions.

How long does treatment for PDA take?

Surgery typically takes about 1 to 2 hours, while catheter treatment takes around 30 to 60 minutes. The recovery period is approximately 1 to 2 weeks for surgery and 1 to 3 days for catheter treatment.