If it weren't for beauty therapist Joanna Mellor's labrador, she probably wouldn't be alive today.

The 24-year-old went into cardiac arrest during the night while sleeping in bed with her boyfriend, Andrew Rayment, 27.

The couple's 5-year-old lab, Leo, noticed that Mellor wasn't breathing and woke Rayment by barking and jumping up at her side of the bed.

"I remember going to bed and drifting off the sleep and the next I know I'm in intensive care in hospital and told I'd suffered a heart attack," reported Mail Online. "The doctors say I was technically dead because it took Andrew 30 minutes to get my heart started. Andrew said he woke up with Leo barking and jumping up at my side of the bed and going mad. He says he could tell something was wrong with me and dialled 999 and the operator talked him through CPR."

After Mellor's scare she was diagnosed with Wolff-Parkinson-White (WPW) syndrome - a condition where there is an extra electrical connection in the heart, causing it to beat faster.

Mellor told Mail Online that she was initially warned that she could be at risk of brain damage because she couldn't feel her legs and one of her hands was "all limp." She has since made a full recovery.

"I owe my life to my dog and my boyfriend," Muller told Mail Online. "If Leo hadn't woken Andrew up I might not be here today."