Defibrillation More Condition_symptoms How Much Time Can One Have Between Heart Failure And Defibrillation In Order To Survive?

How much time can one have between heart failure and defibrillation in order to survive? - defibrillation more condition_symptoms

A friend of mine heart problems and has a chance, say heart failure in itself. Can anyone tell me what is the longest period between failure and cardiac defibrillation is? I wonder how long it takes until the death of the whole brain, so I get a general idea that the paramedic should happen would be given, and if they arrive late or not.

Thank you.