Once, when I was a practicing paramedic, and I really mean practicing (I was not long out of school), my partner and I were dispatched to a cardiac arrest. As partner was driving, I was going through all my mental checklists getting all prepared. Monitor, drugs, where to put the jump bag, what to do FIRST!!!

Fire was already on scene, compressions underway. Helicopter crew was en route. I got this!

We arrive on scene and find mawmaw on the floor in her bedroom ashen gray and compressions underway. I hook up the monitor and find what looks like something of a rhythm, but not one I had seen. Is it a-fib? Maybe. I hook up the pads to the monitor, and loudly say, "I'm clear, you're clear, we all clear." ... DOINK, the shock is delivered and mawmaw jolts. That little squiggly line returns. Somewhere around 2-3 minutes later (I'm a rook, I lost track of time), I had given drugs and it was time to reassess as compressors were switched. Still that dang squiggly line, but now it's starting to look familiar.

I'm doing the ACLS dance, and the helicopter arrives bearing a ride-along doctor I knew. He wasn't acting in an official capacity so he couldn't really give me direction, but I asked him and the flight medic, "Does that look like fib to you?" Doc shrugged, flight medic looked at it a little sideways. I asked the fireman to hold up an extra few seconds on the compressions....

Dangit. That's 60 Hz interference. I've been shocking asystole all this time thinking I had a-fib. I felt like a complete schmuck. Had to think of something fast, so I said out loud (I should have just thought it), something a medic had said in a book, "Well I guess shocking asystole doesn't do any real harm, and besides it's a real crowd pleaser." Unfortunately the entire room burst into laughter.

Made the chat with the family in the other room a bit awkward. Sorry we laughed, but mawmaw's dead.