Here's where we get to the part where I was glad they take the precaution of applying the debrillator pads at the start of the procedure. At 3 different points during the ablation process I went into A-fib. I don't think I've ever had atrial fibrillation before so this was new to me. Same sensation as SVT but different heart rhythm. The doctor later explained that my heart was getting easily irritated and that was causing the A-fib, and he said this may become a more common occurence later in life. Anyway, on each occasion, the nurse gave me something in the IV to knock me out for a few minutes and then they shocked me and continued with the procedure. I never felt anything and to be honest, the first 2 times when I woke up I didn't remember falling asleep and wondered if I had imagined the whole "we need to shock you" thing, but the 3rd time I made a conscious effort to pay attention. They didn't tell me to but I did the whole "count backwards from 10" thing when they injected the drug, and felt myself passing out. Anyway I guess being on the Fentanyl really helped with regard to the whole de-fibrillation thing. I was certainly less worried about it than I would have thought I would be.
Towards the end of the procedure there was a lot of switching cryoablation catheters. My EP doctor later explained that I have an oddly shaped ridge in my heart, near the AV node, and he was having difficulty getting the right angle to ablate the area carefully.
Throughout the procedure there were testing periods where an arrythmic drug is administered and the heart is essentially "driven" with the catheters at increasing heart rates (think of starting with a volume knob at 1 and slowly turning it to 10, then dropping it back to 1 quickly). This is done to see if the ablation has been effective and SVT does not occur. It's pretty unnerving to be laying there at rest on the table, and feel your heart race increasing to 150+ bpm and then drop back down to 80 or so, over and over. It doesn't hurt, but it feels weird.
Finally after 3.5 hours we were done and I was in agony because my back has been flat on this hard, flat table for quite some time, unable to move. I don't lay on my back usually because my back isn't that straight, and I was definitely ready to get out of that position by then. The catheters were removed but the sheaths left in place, and I was transferred to a gurney and wheeled back out into the general cath lab prep area. At this point the nurse (same who did the first prep) explained to me that she would be removing the sheaths. All 4, at once. It took only half a second and certainly didn't hurt, but following removal, pressure needs to be applied at the site for about 10 minutes. So there I am with a nurse's hand pressed down on my groin for 10+ minutes. Luckily she was ready with some small talk to break the tension haha. It was at this point that I discovered the dried blood all over my right hand from the beginning of the procedure. After the 10 minutes had passed, she checked that the bleeding had stopped, and then applied a dressing. Then she left to go begin prep on another patient.
Well, not 30 seconds after she had left me, I felt a warm sensation on my leg and as I reached down to check I felt a very wet bandage. Then I checked my hand... covered in blood for the second time that day haha. Called her back over and we did another 3 minutes of pressure on the area, once again the bleeding stopped, then she re-dressed it and put a "sandbag" on it to keep pressure (I later found out it was two bags of IV saline taped together). This time it held up.
A short while later my EP physician came over to talk to me. He discussed how things went. He said that I had AVNRT and that he was quite sure he had managed to ablate the problem area. He went on to say that unfortunately there was a complication during the procedure because the problem area in my heart was so close to the AV node (and probably also because it was so difficult to reach in its inaccessible location). Despite his precautionary use of cryoablation in this area, some damage occurred to the healthy tissue near the AV node. As a result I now have First Degree AV Nodal Block. What this means is that there is a small blockage of the signal from the SA to AV node causing a slight delay the signal getting from SA to AV, but not enough of a problem to need any kind of intervention, such as a pacemaker. First degree is the least problematic variety and generally there are no symptoms, the only place it can really be noticed is on an ECG printout. This specific risk was brought up by my EP doctor during the consultation and at the time he mentioned it was a 1 in 500 risk. Overall, I'd rather have a heart that's 1% less efficient than having to deal with SVT several times a year with possibly multiple trips in an ambulance. It was a risk worth taking.
He went on to say that he would be keeping me overnight in the Cardiac Short Stay Unit to be observed, both because of the AV nodal block and also because of the A-fib episodes. I was disappointed not to be going home but it was no big deal. I had a really fantastic nurse in the CSSU who was constantly checking on me and got me anything I could possibly need. I was kept on heart monitor and the dressing on my groin was checked every hour until lights out. Following that, I really didn't need any attention at all, but I didn't sleep too well either. At 6'4", the bed was not really sized for me to sleep comfortably. I maybe got 2 hours in. I spent a lot of time on the internet on my laptop. On a connection frustratingly too slow for Netflix, even in the middle of the night when 95% of people were probably asleep lol. I went home in the morning after a brief visit from the EP physician.
Since the procedure, I have not had any SVT but I have had some skipped beats, extra beats, and generally just a few seconds at a time of odd feeling in my chest if I do certain things such as bend over. I'm having a 48 hour holter monitor test next week and then a follow-up with the EP physician a month later. I attribute the odd heart beats to my heart still healing. It's the only muscle in the body that doesn't get a chance to heal at rest following an operation, and it's understandable that the heart would feel a little off for a few weeks afterward. Some other posts I've read here and elsewhere seem to echo this experience.
So, there is my experience with ablation. If you're worried about your ablation procedure, my advice is to educate yourself as much as you can. There are several good videos available on YouTube, and lots of posts such as this where people discuss their experience. I went into the procedure cautiously worried, and to be honest most of that worrying was due to my weight, and I still came out pretty darned good. Considering that I went in worrying I wasn't going to come out alive, I was definitely more worried than I needed to be. The procedure has moments of discomfort, no question, but there is no real pain involved. It's certainly worth a few hours of discomfort for a lifetime of relief from SVT.