A doctor is under investigation after footage of him beating a patient who had undergone heart surgery just hours earlier emerged.

The patient died soon after the incident at the Federal Centre for Cardiovascular Surgery in Perm, a city in the Urals, though it is not believed his death was related to the attack, Sky News reports.

Anaesthesiologist Andrey Votyakov was filmed punching the patient in the head and chest in the security footage which displays the date February 21, 2013.

russian doctor andrey votyakov punching patient

Anaesthesiologist Andrey Votyakov says he lost his temper after the patient began insulting him

Votyakov told Russia’s Life News he had been working 36 hours straight and lost his temper after the patient reportedly insulted him.

In a translation provided by the Moscow Times, Votyakov said: "As soon as fellow medical personnel and I approached the patient, he began to insult me with some detestable words. That's when I, so to say, went berserk. We had worked for a long time on this difficult patient … and no thanks whatsoever!"

"I am very sorry for what happened and I want to apologise first of all to the patient himself and his family," he added in a report in The Mirror.

The alarm was raised by the chief public affairs officer at the Russian Interior Ministry when he saw the video on YouTube, Yahoo News reports.

Votyakov, who was head of anaesthesiology and intensive care at the hospital, was fired after the incident became public.

A police spokesman in Perm said: “We saw the video which went on YouTube. We are investigating it and checking the details of what happened.”