Chula Veterinarians Achieve National First with Pacemaker Implant in a Cat 

In a groundbreaking medical achievement for Thailand, veterinarians from Chulalongkorn University’s Faculty of Veterinary Science have successfully implanted a pacemaker in a cat for the first time in the country. The procedure, led by Assoc. Prof. Dr. Anusak Kijtawornrat, from the Department of Physiology, marks a new milestone in advanced veterinary cardiology and demonstrates Thailand’s growing capability in high-precision animal healthcare. 

From Mysterious Fainting to a Life-Saving Diagnosis 

A veterinary team led by Assoc. Prof. Dr. Anusak Kijtawornrat, of the Department of Physiology, Faculty of Veterinary Science, Chulalongkorn University, has performed Thailand’s first successful pacemaker implantation in a cat. The patient, “Pepsi,” an eight-year-old female domestic shorthair cat, had been suffering from frequent fainting spells — as many as three to four times a day. After the procedure, Pepsi has fully recovered, regaining her strength and playful personality, and now enjoys a normal, quality life. 

Dr. Anusak recalled that Pepsi’s owner initially brought her to the Chulalongkorn Small Animal Hospital with symptoms of lethargy, weakness, and sudden collapse accompanied by muscle stiffness and occasional vocalizations. Initial tests suggested possible neurological or cardiac issues, but medication failed to improve her condition. 

Further examination at Chulalongkorn revealed the true cause: a severe cardiac arrhythmia — specifically a blockage of electrical signals between the atria and ventricles. This prevented the lower chambers of the heart from pumping enough blood to the brain, resulting in fainting episodes. 

“Normally, a cat’s heart beats about 140–220 times per minute, regulated by natural electrical impulses,” Dr. Anusak explained. “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.” 

Accurate diagnosis relied on Holter monitoring, a 24-hour electrocardiogram device that is far more precise than the standard 1–5-minute ECG test. 

A Complex and Delicate Surgery 

Implanting a pacemaker in a cat presented major challenges. Unlike dogs, where the pacemaker lead can be inserted through a neck vein, cats have smaller veins and thinner heart muscles, just about 2 millimeters thick. This made the standard technique too risky, as the lead could puncture the heart. 

To overcome this, the surgical team opened the chest cavity between the ribs to access the heart directly. They attached the pacing lead to the heart’s surface and connected it to a small generator implanted under the abdominal muscles. 

“This method is more complex but safer for small animals,” Dr. Anusak said. “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.” 

The entire operation took about one hour and involved a multidisciplinary team — including cardiologists, surgeons, anesthesiologists, and cardiovascular intervention specialists — working in close coordination. 

Human-Grade Technology, Adapted for Cats 

The pacemaker device used in Pepsi’s surgery is the same model used in humans, customized with appropriately sized leads. The pacemaker unit itself costs around 45,000 baht, while the leads add another 10,000 baht. Fortunately, Pepsi’s device was donated and sterilized for reuse, significantly reducing costs for the owner. 

Post-surgery, Pepsi made a swift recovery. She no longer experiences fainting, eats normally, and interacts energetically with her owner and other cats at home. She will continue to undergo checkups every three months to ensure the pacemaker is functioning properly. 

Advancing Thailand’s Veterinary Medicine 

Dr. Anusak noted that while pacemaker implantation in cats has been practiced abroad for years, it remains rare in Thailand due to diagnostic challenges, specialized training requirements, and equipment costs. 

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

After surgery, cats can live normally with few restrictions — they can play and even swim. However, owners must inform veterinarians before MRI scans, as strong magnetic fields may interfere with the device. Risks after surgery are minimal, at only about 1–2%, such as minor lead dislodgement, which can be corrected surgically. 

A Message for Pet Owners and Future Vets 

Dr. Anusak urged pet owners to seek immediate veterinary care if their cats or dogs show signs of weakness or fainting. The Chulalongkorn Small Animal Hospital — also known as the Bangkok Animal Hospital — operates 24 hours a day, providing specialized emergency and cardiac care. 

He also offered words of encouragement to veterinary students: 

“Veterinary medicine evolves rapidly. Our students must continue to learn and adapt. With solid foundations and continuous self-improvement, what once seemed impossible in Thailand can become reality — advancing our profession to new heights.” 

For more information: 
Chulalongkorn University Small Animal Hospital (Bangkok Animal Hospital) 
Tel: 0-2218-9715 
Email: sah.vet@chula.ac.th  

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