A defibrillation system that includes a first defibrillation device and a second defibrillation device. The first defibrillation device including a therapy module, a communication module, a physiological parameter module and a timing control unit. The second defibrillation device including a therapy module and a communication module. The timing control unit configured to output an instruction to cause the therapy module of the first defibrillator and the therapy module of the second defibrillator to each discharge an energy delivery according to a timing relationship.