A lab assistant had to watch a YouTube tutorial video to perform a heart test on a patient - because all the doctors were away for Diwali.

The worker from a state-run hospital in Rajasthan, India, was roped in to carry out the ECG test on a sick patient when his colleagues were away on October 31.

Footage shows the assistant scrolling through how-to videos on his smartphone while trying to figure out how to run the machine.

He was fixated on the video while the patient and his companion questioned him if he knew what he was doing.

Due to the incident, the hospital became under administrative investigation as the patient's family expressed safety concerns.

However, the lab assistant defended himself, saying he had no other choice.

He said: 'I have never performed an ECG before but there was no other medical personnel available at the time.'

The hospital reportedly had a shortage of medics at the time due to the holiday, but an investigation was launched to determine negligence.

An ECG, or electrocardiogram, is a medical test that records the electrical activity of the heart over a period of time. It is often performed in emergency departments when patients arrive with chest pain, shortness of breath, dizziness, or palpitations.

Diwali is a major Hindu festival celebrated by millions worldwide, particularly in India, Nepal, and other countries with significant Hindu populations. It is often called the 'Festival of Lights' and symbolises the victory of light over darkness and good over evil.