The EP will ask the anesthesiologist for an assessment since it is that person's responsibility to ensure you are suitably sedated. Some patients have had to endure a catheter ablation while conscious, although they would have been offered some sedation if they became agitated or uncomfortable.

I was conscious for my angiography, which involved inserting a catheter through my radial vein. I felt the catheter zip up the vein, to my armpit, but after that there was zero (0) sensation. The surgeon asked if I wanted any sedation after I mentioned that I had felt the catheter move up my arm, but I declined. I was good, and I'm a curious fella who wants to see and to understand as much as possible.

During a standard RF catheter ablation, there is often the requirement, for the patient's safety, to insert a trans-esophageal echocardiogram (TEE). This is something like a sigmoidoscope that is inserted into the anus during a colonoscopy. This one goes down the throat, the esophagus, and it is used to monitor the position of the RF wand to ensure it doesn't get too close to the Vagus nerve, the phrenic nerve, or the esophagus, all of which CAN BE burned by a less-than-careful electrophysiologist. You can understand that, with you flat on your back, head tilted well back so that the esophagus doesn't bend enough to make insertion of the TEE a problem, and then having that 1.5 cm thick probe slid down your throat....yeah, you want to be out for that. So, it's either propofol or something else, with the modern preference being for propofol. Especially for older patients who might require general anesthetic for something else before too long, or who recently had a general, you want as little exposure to general as possible. Hence, a strong preference for propofol.

As for duration, anywhere from 12 minutes to three hours, maybe four in really complicated ablations. I say as little as 12 minutes because some other unforeseen incident, or condition in your heart, or other intrusion makes the continuation of the procedure impractical or dangerous, or unethical. No sense in speculating about which of those might be the case as that would be an extremely rare and unlikely event. My own two ablations lasted about 90 minutes each. I was awake and alert about 30 minutes later.

The nurse looking after you will ensure you lie still, even keeping your head on the pillow and not raising it. This will last for at least three hours, and you'll have a heavy compress or bandage with a weight on the groin incision(s). At about three hours, they'll ask you to drink, and if you can do that, to eat a muffin or whatever, and if you can keep that down, to rise and carefully walk around the ward. This is to ensure your safety and to ensure your blood pressure is high enough to allow you to stand and to move on your own. While you're making your second or third lap, your 'ride' gets texted and told you are going to be released to that person very shortly. You will be legally impaired for 24 hours after your release, not from the time you get wheeled back, unconscious still, into the recovery ward. So, you'll need a taxi at the very least, or a friend/relative to take you down to the vehicle and drop you off at home.