Mum Kim Reynolds, 41, was confused by her pet Doberman Saraya’s unusual ”needy” behaviour around six-month-old Alexander.

A baby’s life was saved after the family dog detected that he had a racing heartbeat. (Image: William Dax / SWNS)

Saraya wouldn’t leave the baby’s side and cried every time he was taken away from her that morning.

Alexander later became upset and looked unwell, and his mum rushed him to Royal Bournemouth Hospital’s A&E department.

Doctors discovered Alexander was suffering with a dangerously fast heart rhythm, at 280 beats per minute.

Two days later he was diagnosed with Wolff-Parkinson-White syndrome.

Kim, a former canine hydro-therapist and first-time mum, said: “Saraya knew his heart rate was higher than it should’ve been.

”I had no idea. She sensed it. I dread to think what would have happened if I just put him in the cot and walked away.”

When she went to A&E in September for seven-month-old Alexander, Kim feared they were wasting professional’s time as he had stopped crying.

Then she found out how fast his heart was beating.

In order to shock Alexander’s heart rhythm back to normal, they had to “dunk him” in a large bucket filled with cold water and ice.

Kim, of Shepton Mallet, Somerset said: “They put him in and the scream was horrific, that’s all I hear now.

”They did it twice and his heart rate still hadn’t come down.”

A baby’s life was saved after the family dog detected that he had a racing heartbeat. (Image: William Dax / SWNS)

She then decided it was “enough” and she wanted them to try intravenous medication.

Three doses of the medication finally brought his heart rate down and the family was transferred by ambulance to Poole Hospital.

Kim stayed for two nights and received his Wolff-Parkinson-White syndrome diagnosis.

Kim described the syndrome as ”an extra but of tissue in his heart, which basically means electrical pulses can get through where they shouldn’t That’s when he can’t calm his heart rate”.

Alexander now takes the beta blocker propranolol three times a day through a syringe.

Kim said he “knows he needs it” and drinks from the syringe himself “hassle free”.

This month, Saraya began acting different around Alexander again.

A baby’s life was saved after the family dog detected that he had a racing heartbeat. (Image: William Dax / SWNS)

Kim said: “He was in his bouncer and she was next to him, licking his hands, looking at me.

”My first thought was ‘oh god are we going to go into SVT again’.”

After checking his pulse, she noticed his throat looked red and took him to A&E.

He was diagnosed with bacterial tonsillitis and prescribed penicillin.

Kim said: “I 100% trust Saraya.