It was a pleasant morning, walking around the British Wildlife Centre with Matthew Green, his wife Gill and Dylan, their six-year-old son. But one thing was disconcerting -- the constant "bedump, bedump, bedump" noise that came from the backpack Matthew was carrying.
It accompanies Matthew wherever he goes -- even when he's asleep or goes to the toilet.
And for good reason -- the noise comes from the pump that powers the artificial heart that surgeons at Papworth hospital implanted in his chest nine months ago. Its unrelenting "bedump, bedump" is keeping him alive.
Matthew had Chronic Heart Failure and has been on the Transplant waiting list since September 2010. Last summer his condition was deteriorating rapidly and he was admitted to Papworth.
He told me that one week he could just walk the length of the ward to the loo. The next week, he couldn't even walk across the ward. He liver and kidneys were failing. His skin cracked -- so much so that he bled from his fingertips.
Then doctors offered him the chance to go on the artificial heart. He'd be the first patient in Britain to get one - though several hundred have been implanted in other countries. It was a no-brainer. As Matthew told me, without the machine he had only weeks to live.
He's now in good spirits and getting about with his wife Gill and Dylan. They told Dylan his daddy had a "robot" heart and he thought that was really cool -- on a camping holiday he brought all the kids from the playground to come and look at his dad's "robot" heart
And although its keeping him going, he's still on the transplant list. The machine is a "bridge" to keep patients alive until a suitable heart becomes available.
On average, they figure three years. Matthew has now been on the list for 19 months - along with around 160 other patients waiting for donor hearts and over 7500 waiting for hearts, livers, kidneys and other organs.