Thailand makes history with nation's first cat pacemaker surgery

Veterinary professionals at the Chulalongkorn University’s Faculty of Veterinary Sciences successfully performed a pacemaker implantation on a Pepsi, an 8-year-old domestic shorthair cat, making it the first in Thailand’s history.

Pepsi suffered from frequent fainting spells, up to 4 times a day, that was caused by severe cardiac arrhythmia. She was initially brought into the Chulalongkorn Small Animal Hospital with lethargy, weakness, and sudden collapse accompanied by muscle stiffness and occasional vocalizations.² During primary testing, it was possible she had a neurological or cardiac issue, but medication did not improve her condition. After being examined further, she was diagnosed with a severe cardiac arrhythmia.

Pepsi’s condition stemmed from a blockage of electrical signals between the heart’s chambers which prevented blood from reaching the brain. In feline patients these arrhythmias are rare and often occur in older animals. Pepsi’s team was able to confirm through 224-hour Holter monitoring, which is a more accurate tool than standard ECG testing.¹

“Normally, a cat’s heart beats about 140–220 times per minute, regulated by natural electrical impulses,” Anusak Kijtawornrat, DVM, PhD,explained.² “When the signal is blocked, the heart stops contracting effectively, causing syncope. Such cases are uncommon — around 10% of feline cardiac cases — but are more prevalent in older cats.”

The procedure, and its challenges

For feline patients, implanting a pacemaker can have major challenges because cats have smaller veins and thinner heart muscles, unlike canine patients where the pacemaker lead can be inserted through the patient’s neck. Because of the challenges, the standard technique is too risky and could potentially puncture the patient’s heart.

The surgical team needed to open the chest cavity of the patient between the ribs to access the heart directly. Then, they attach the pacing led to the heart’s surface and connected that to a small generator implanted under the abdominal muscles.² The procedure in its entirety took 1 hour and involved a multidisciplinary team working in close coordination.

“This method is more complex but safer for small animals,” said Anusak.² “It was an improved technique from our previous feline case just two weeks earlier. Switching from a diaphragmatic approach to a thoracic one made the implantation easier and more accurate.”

Pepsi’s pacemaker device is the same model that is used in humans that was customized with appropriately sized leads, and for Pepsi the pacemaker was donated and sterilized for reuse. Following the procedure, Pepsi made a quick recovery. She no longer experiences fainting, interacts energetically with her owner and the other cats at the home, and eats normally. She now visits the hospital every 3 months for follow-ups, but overall lives a normal life.¹

Feline patients who receive this surgery can live normally, but with some small restrictions. When at the veterinarians, owners whose pet has had this procedure must inform their veterinarian before MRI scans, and a minor lead dislodgement can occur in about 1-2% of patients but can be corrected surgically.²

A major veterinary medicine advancement for Thailand

While this procedure has been practiced outside of the country for years, it is rare in Thailand due to the specialized training requirements, diagnostic challenges, and equipment costs.

“This success showcases Thailand’s readiness to perform advanced procedures at an international level,” Anusak concluded. “Chulalongkorn’s veterinary faculty now has the expertise, technology, and multidisciplinary collaboration to match global standards.”

Anusak also urges clients to seek immediate veterinary care for their pet if they show signs of weakness or fainting.

Reference

1. Chula Veterinarians Perform Thailand's First Pacemaker Implant in a Cat. News release. Chulalongkorn University Communication Center. November 23, 2025. Accessed December 3, 2025. https://prnmedia.prnewswire.com/news-releases/chula-veterinarians-perform-thailands-first-pacemaker-implant-in-a-cat-302624230.html
2. Panlee S. Chula Veterinarians Achieve National First with Pacemaker Implant in a Cat . Chulalongkorn University. November 14, 2025. Accessed December 3, 2025. https://www.chula.ac.th/en/highlight/271336/