Further, after discussion with 'Her Majesty', the consensus is it's more likely to be an issue with the Garmin rather than your ticker! Would a general enquiry with their tech guys be useful? Have you tried repositioning the signal monitor slightly? I think it should be picking up the strongest impulse and, after the ablation, that may have moved slightly so the monitor is now picking up the initial 'beat' followed by several lesser impulses?
Of course that is probably all just bollocks, and you carry on as usual and ignore me!!
No idea Dusty, would it be worth recording it and taking the info back to your consultant? Do some ablation procedures require a couple of 'goes' to get the heart working correctly? When I googled it there was also the suggestion that the procedure was more successful in younger people so, at 60+, you've got no chance!!