It was a heartbreaking cat-astrophe.

A Queens woman claims her beloved pet was “murdered” by an Upper East Side veterinarian and is suing for $3 million.

The tuxedo-coated Misia was just a kitten when she first wandered into Alina Kedzierska’s East Elmhurst yard 15 years ago.

The furry companion eventually made her way into Kedzierska’s apartment and found a way into her heart, becoming a “daily companion and beloved friend” who would greet her at the door when she came home from work, Kedzierska said in legal papers.

So when Kedzierska, 57, woke one day in June 2020 to hear Misia crying, “stretched out on the floor next to her bed in a strained position” and unable to move, she rushed her four-legged friend to the Animal Medical Center on East 62nd Street.

After an examination, senior veterinarian Lauren Saunders, who has been at AMC since 2019, told Kedzierska the cat “has suffered from neurological dysfunction and most likely had a stroke,” and “there was nothing else AMC could do for Misia and that euthanasia was the only option,” according to the lawsuit against the vet and AMC.

A “heartbroken” Kedzierska agreed, only to learn the next day from a local vet that there were medications which could have treated Misia and kept the pet alive.

“There was clearly a lack of informed consent, including tests and treatments for cats who suffered from a stroke,” Kedzierska alleged. “If Dr. Saunders had properly treated Misia and administered anticoagulant therapy, Misia could be alive today.”

To add insult to injury, AMC allegedly lost Misia’s remains for two days, then mistakenly ignored Kedzierska’s request for a necropsy at College of Veterinary Medicine Pathology Department, she claimed.

Instead, Misia’s body was cremated before Kedzierska could retrieve it, she said.