The procedure itself is not too involved. When I go in (I am still having it monthly as an outpatient), I walk into the procedure room and lie down on a stretcher. They put a blood pressure cuff on, insert the IV needle, and then I am out. While I am out they apply electrodes and give the shock so I can have a seizure, and once the seizure happens they wheel the stretcher into the recovery room. Then I wake up in the recovery room. They ask me if I know where I am and what I had done (yes and yes), I wait awhile and then go.
Speaking of which, though, you should make sure they know you have had seizures in the past. I am not a doctor and am not qualified to tell you these things, but just be sure that you have given them all your information. Also, as you read, you will see that there are two different types of ECT - unilateral and bilateral. Ask your doctor about this.