A heart murmur in a kitten leads to the diagnosis and treatment of patent ductus arteriosus

A heart murmur detected during a routine examination of a rescued kitten ultimately led to the diagnosis and successful surgical correction of patent ductus arteriosus (PDA), a congenital cardiac defect that can be fatal if left untreated. Managed at the Schwarzman Animal Medical Center (AMC), the case highlights the value of early auscultation, further diagnostic evaluation, and definitive intervention in young feline patients with suspected congenital heart disease.

The kitten, found in the street by a Brooklyn-based rescue organization, appeared outwardly healthy.¹ According to the AMC, he was active, playful, and “full of kitten energy.” However, a severe heart murmur noted during his first veterinary visit prompted further evaluation.

Additional testing confirmed PDA, a condition in which a blood vessel that should close after birth, the ductus arteriosus, fails to do so, resulting in abnormal blood flow between the aorta and pulmonary artery.^2,3 Approximately only 1 in 5000 cats are diagnosed with PDA.² Still, the condition is the most common shunt in cats.

Clinical background

Before birth, the ductus arteriosus allows blood to bypass the lungs, which are not yet functioning. The vessel normally closes shortly after birth. When it remains open, blood flows back toward the lungs, increasing circulation through the pulmonary vessels and placing added strain on the left side of the heart. Over time, this can lead to heart enlargement, excessive pulmonary blood flow, and left-sided heart failure.²

Congenital heart defects are estimated to affect approximately 1% to 2% of newborn kittens, and most cases of PDA are detected during the first veterinary examination, often before clinical signs develop.³ Early recognition is important, as delayed surgery can lead to irreversible cardiac changes. Without surgery, prognosis is poor, with death from congestive heart failure occurring between 1 month to 5 years of age, according to the Cornell Feline Health Center.³

Diagnosis

In kittens, a continuous “washing machine murmur” that sounds like water being agitated through a wash cycle should raise suspicion for PDA. Veterinarians should thereafter recommend radiographs and an echocardiogram.² According to VCA Animal Hospitals, an echocardiography is required to definitively diagnose a PDA.² Doppler echocardiography is used to assess shunt location, flow direction, and velocity, helping define its hemodynamic significance.

Treatment and outcome

Treatment for a forward-flowing PDA focuses on closing the abnormal vessel to stop blood from flowing through the shunt. This is most often achieved through surgery and, in select cases, less invasive cardiac catheter-based techniques. According to VCA Animal Hospitals, however, these procedures are harder to perform in cats due to the animal’s small size.²

Early surgical repair is advised to reduce the risk of permanent heart damage, with presurgical stabilization needed for cats exhibiting signs of heart failure, according to VCA Animal Hospitals.² Reverse PDA cannot be surgically corrected and has a poor prognosis.

The AMC team performing surgery on the kitten. (Video courtesy of Schwarzman Animal Medical Center)

At the AMC, Robert Hart, DVM, DACVS, head of the AMC’s surgical service, performed the repair on the rescued kitten, successfully closing the ductus, which restored normal blood flow and cardiac function, relieving the strain on the kitten’s heart.

According to AMC, the kitten went on to make a full recovery and was later adopted by Christal Luna, LVT, a member of the kitten’s care team at the AMC. He was named Finn.

“Today, more than 2 years later, Finn is healthy, active, and far removed from the uncertain future he once faced,” the AMC wrote in a news report.¹ “At home, he thrives alongside his feline siblings and has a hearty appetite. Christal affectionately calls him her ‘scrunchie boy’ for the way he scrunches up his nose when his chin is scratched just right.”

Editor’s note: The AMC is unaffiliated with Vetmedin Solution, and the content of this article has been in no way influenced by the awareness month sponsor.

References

1. Stacy G. Healing a tiny heart: an AMC love story – from “hart to heart.” StacyKnows blog. February 10, 2026. https://stacyknows.com/healing-a-tiny-heart-an-amc-love-story-from-hart-to-heart/
2. Barnes C, Weir M, Yuill C. Patent ductus arteriosus in cats. VCA Animal Hospitals. https://vcahospitals.com/know-your-pet/patent-ductus-arteriosus-in-the-cat
3. Ask Elizabeth: patent ductus arteriosus. Cornell Feline Health Center. https://www.vet.cornell.edu/departments-centers-and-institutes/cornell-feline-health-center/health-information/feline-health-topics/ask-elizabeth-patent-ductus-arteriosus