My Brother died 2 years ago from one of these bursting and another Brother is clear of the problem.
Still, it is worth knowing so that adjustments to timing and mixture can be applied and maybe a change to synthetic oil.
All these findings and i feel perfectly OK and never feel ill at any time.
This AAA check is done as you approach 65 and they just ask you to come in for a test. I think it is worth knowing that there is a defect and now it will be measured every year. Dont panic !