I'm a new grad who has been on a step-down floor for a few months now, and I'm getting ready to take ACLS. I've come across something I'm totally not familiar with, and I'm freaking out because I feel like I ought to know what it is. There are several questions about "ventricular fibrillation that has been refractory to an initial shock" or "to a second shock." What on earth does that mean? V-fib can be induced by a defibrillation during the refractory period, right? Is that what they mean--that a doctor or nurse used a defibrillator and it shocked (once or twice, for "initial" or "second") the patient and sent them into v-fib? I'm not trying to get someone to give me the answers--the questions are actually about pharmacology--but I am panicking that I'm not going to have any idea what they're talking about in class. Yikes!