Additionally there is what is called after drop. This is what generally triggers the V-fib. The body slows to almost the point of shutdown of blood flow to the extremites to try to conserve core temp. This is what usually leads to frost bite of fingers and toes. When the body is warmed the core temp goes up first. Then the body recommences flow to the arms and legs to restore their function. But the blood there is usually much colder than the core. Like pouring ice water into a pot of boiling water. This causes the core temp to rapidly drop. This shock of the sudden after drop causes a drastic shock to an already weakened system. This is the shock thatoften triggers cardiac arrest.