Playing in the kitchen and happily chatting away, Tommy's mum Candice, 29, realised something was wrong when he fell silent and limp.
Realising he wasn't breathing, she shouted to her partner Neil to ring 999 as she ran upstairs to him with Tommy in her arms.
East Midlands Ambulance Service (EMAS) call handler Stacey Byard answered the call from Neil and immediately provided CPR instructions over the phone, giving baby Tommy the best chance of survival.
Candice said: "At first I thought Tommy was happily playing until I realised he had gone completely silent.
"His dummy fell out and he flopped to the floor.
"Panic washed over me when I saw he wasn't breathing but my partner Neil was so calm thanks to the help of Stacey."
Within four minutes, community first responder Alison Curtis arrived on the scene and took over.
For Alison, seeing Tommy brought back her own experience when her son went into arrest which inspired her to become a community first responder.
One minute later, technicians Adam Fardon and Vruthi Patel arrived on scene, making the decision to shock Tommy.
They were then followed up with the support of paramedic Michelle Broughton.
After shocking Tommy, Adam, Vruthi and Michelle immediately decided he needed to get to hospital.
Baby Tommy arrived at Queen's Medical Centre conscious and alert and was later transported to Glenfield Hospital where he spent three weeks recovering.
Now 16-months-old, back at home in Nottinghamshire and recovering well with his parents, Tommy has been fitted with an internal defibrillator designed to shock him if his heart stops again.
Alison said: "It's wonderful to see Tommy recovering after what was a very traumatic time for all involved.
"Thanks to the incredible teamwork shown by everyone, both Candice and Neil are able to have those cherished moments with their lovely little boy."
Candice and Neil said: "We want to thank everyone involved for helping to save our little boy.
"We are exceptionally grateful for how quickly they acted, making sure Tommy had the best chance of making it.
"We will never forget how brilliant they were."