What is a Cardiac Ablation?

I had a check-up go horribly south at my cardiologist last thursday. I went in for a check up because I was diagnosed with mitral valve prolapse in December. He did an EKG on thursday and was not happy with my p wave. He said there is something long with an electical circuit in my heart. He and 2 orther doctors were clueless as to what is causing this and my symptoms. He mentioned doing an ablation. What is it like to have an ablation? How out of it will I be when they do it, because they typically don't put you to sleep? Will I have to stay in the hospital afterwards?