Ok, so this a actual case:

In this facility, all elective cardioversions are performed in the PACU by the cardiologist and CRNA. Today there are 3 patients lying side-by-side(all for a-fib). The anesthesia tech already started the IV's, connects all patients to the PACU monitor (3-lead, NIBP, spo2) and applies the defibrillator pads in the anterior-posterior position as per protocol. This way after a cardioversion is finished, the crashcart can be moved to the next patient, plug the pads and sync cable into the monitor and start again.

So after the first 2 patients are finished, you move to the 3rd one. Patient gets 160mg propofol and he's off to sleep, spontanious respiration. You give the cardiologist the OK to start. The defib is sync'd, charged to 100biphasic and the cardiologist presses (and holds) the shock button.. And again.. Nothing happens.

What went wrong?