Karatzas was found guilty by a jury of murdering the 68-year-old woman.
“I accept that you are remorseful for what you have done,” Justice Beale said in sentencing.
He had suffered from depression for years 15 years and “snapped” the day he killed his wife after a disagreement between them, Justice Beale said.
“Tragically … after a disagreement you snapped and strangled her with an electrical extension cord until she collapsed … and you fled the scene.”
Mrs Karatzas’ elderly mother, who lived with the couple, found her daughter dead and facedown in the laundry, dressed in her nightie, with the extension cord protruding from beneath her body.
She died from compression to the neck and also received blunt-force trauma to the head.
Her husband then left the family’s home and was reported missing before being arrested when he turned up at his sister’s house the next day.
“[There are] no excuses for what I’ve done. I’ve done it,” prosecutors said Karatzas told police.
Karatzas has already served 674 days behind bars.