See my parallel comment. Aside from a possible genetic defect, it's quite possible that this person is healthy by all normally measured features. In the general case, a hunter gatherer lifestyle would likely have triggered this sooner, if anything.
A genetic defect, if not impacted by lifestyle, would do the trick. However, 'normally measured features' may not fully capture cardiac health.
I'd still like to see studies of cardiac arrest among hunter gatherers, or as another poster commented, primates. Lots of genetic problems can be impacted by lifestyle (epigenetics).
I don't know about about the condition you posted to say how lifestyle affects gene expression in that case.
Assuming the disease isn't strongly affected by gene expression, my statistics are likely off then. Wikipedia listed the condition as having a .2-.5% prevalence.
