Severe cases of heart attack or stroke require combination of Yang and Yin approaches.
First is generally for emergency help, fast-developing situations and sudden and rapidly changing symptomes, and done on meridians, second is for deep-rooting, slowly-developing and similar, also for deeply located problems, done on boyl-chakras.
"2-path scheme" belongs to first, and allows both fundamental (Diamond Energy System) and fast (Border meridians) action, making Light-Darkness schemes valuable for emergency and life-threatening
situations like car accidents, eye traumas, heart attack, stroke etc.
Such schemes turned out compatible with treatment on boyl-chakras on the same hand, i.e. for deep-rooting problems, which may be a solution to treat severe brain damage, for example.
If do chakral treatment on fingers joints (Neitro-system), both schemes seem to interact and coordinate
Treatment on boyl-chakras is too demanding for non-professionals and is not covered here.