You don't know what you don't know until you know it, is how I view my svt journey. I have had avnrt my whole life but actually thought it was normal that your heart started to beat really fast after exerting yourself. I didn't think to ask anyone about it because it always stopped on it's own and I kinda thought maybe I was just hyperventilating. It wasn't until it started to happen more frequently later in my life that I started to wonder what was going on. But I had no clue that I also had a lot of premature beats, pacs and pvcs. I thought it was all one in the same not realizing they are two separate issues. So looking back I was having tons of extra beats right prior to my ablation. It would sometimes feel like someone was poking me in the chest which I suspect was some sort of bigeminy pattern of extra beats but I was having daily symptoms and more frequent svt episodes as well. I even had a bunch of them on the holter monitor I had the first time to capture the svt and was told everything came back normal. I had an episode the day after, not the day I was wearing it so I didn't question the normal findings. It really wasn't until after they went totally crazy after my ablation that I kinda freaked out about them. I had a week, probably 5 weeks after my ablation, where I think I was in some sort of premature beat storm or maybe in afib because my heart was beating so erratic I couldn't eat or sleep. I probably should have went to the ER but I didn't and just chose to make an appointment with my EP. By the time I went to see him they had settled down quite a bit. But I think it is pretty common for patients to have a rise in extra beats after an ablation. It is also common to have them after an episode of svt. It actually took a few years for them to settled down to a handful of them a day. I still get the premature beats and suspect I always will but I don't notice them as much anymore.
That said, what I didn't know prior to having the ablation is that they feed off each other. AVNRT happens when the signal on the extra pathway, which is slower, reaches the center of the avnode and then goes out the normal entrance. That slower signal is usually blocked by the normal pathway signal reaching the center first. But if one has a premature beat the signal gets thrown off for a second giving the secondary pathway a chance to complete it's circuit thus creating a stuck loop around the entrance of the avnode. An EP can probably explain it better but think of the avnode as like a revolving door. Most people come in from one entry point but there is a second entry point and if someone manages to come in that way then they get stuck going around the revolving door super fast. Not the best analogy but maybe it will give a good visual for you. Essentially the pause from a premature beat or a group of them gives that secondary pathway a chance to beat the regular pathway in the door blocking the regular signal from the sa node from doing it's job. Interestingly enough, another premature beat can actually stop the svt attack as well. Essentially you want to disrupt the heart beat to break up the stuck circuit. Holding your breath and bearing down, drinking a cold glass of water are triggers for a premature beat that can disrupt the signal to stop as well as start and svt episode. The medicine they use, adenosine, actually stops the heart for a second, thus resetting the heart beat pattern. Premature beats act in a similar way. Premature beats don't actually stop the heart beating like the medicine does but if two beats happen too fast together there is a pause in the finishing of the beat because there isn't enough blood in the heart to complete the heart beat.
Again, I may not be totally accurate on the exact science of this so a doctor may have better info but that is kinda how I understood things from a layman perspective. Premature beats don't stop the heart they just disrupt the normal pattern hence giving svt a chance to start and stop for that matter. You may be less likely to have a premature beat during super fast heart rates like in cases of avnrt where the beat is well into the 200s so that may be why they can be hard to stop and some need the medicine. But unfortunately, premature beats happen after the heart becomes over stimulated or irritated for some reason. Sometimes there might not even be a good reason, maybe just a weird posture change, but if they trigger an svt episode that in and of itself stresses the heart and makes it irritated so it stands to reason that there would be more premature beat activity after an svt episode which sets the stage for more svt episodes and then more premature beats, so on and so forth. For me, and it sounds like for you as well, things can escalate where the heart is irritated too soon and too often leading to more episodes and more extra beats leading to multiple svt episodes a week. How many you were having is pretty rare I think but something was set in motion allowing for the secondary circuit to have easy access to the avnode. Hopefully with your second ablation they can find the correct spot or multiple spots and block them. Though I would definitely question them why they did not do an EP study and mapping. Very odd he would say they try to avoid it. Seems like the most important aspect of doing a cardiac ablation to know where to ablate. Here is a link to a Mayo Clinic info on an EP Study. Maybe read up on it a bit and ask the EP to explain himself. Or find a new EP. I would think if they don't do mapping anymore for avnrt that Mayo would have info on that but can't understand why it would be avoided.
But to answer your question, I had a lot of premature beat activity the six months leading up to the cardiac ablation and a ton of them after the ablation. I can't say for sure how many I was having prior compared to after the ablation because I wasn't conscious of what was actually going on so I wasn't monitoring my heart as much until after the ablation and I was expecting a quiet heart. I wish someone would have explained the premature beat issue to me. No one said anything and so I freaked out not understanding what was going on with my heart after the ablation. I think some doctors don't say anything to not worry the patient but for svt patients it might be prudent to talk to them about it so they don't get confused and know what to expect because a rise in premature beat activity is pretty common after an ablation.
I would say, as your heart is healing, avoid caffeine if you can. Spicy foods and foods that cause stomach gas. Stay well hydrated. Stomach issues and dehydration are two of the biggest triggers, along with stress, for causing premature beats. Doing these things may not stop you from having them as your heart is still probably irritated from the ablation but it could help lessen the amount you are having giving your heart a little more room to heal faster.
I'm sorry to hear the ablation wasn't successful. It's possible at your young age that the tissue healed over instead of scarred up. SVT is caused by having extra muscle fibers in the heart that create secondary pathways in various areas of the heart. This can create a situation where the heart beat signal gets caught in a loop cirumventing that natural pacemaker and depending on how small the loop is, making the heart beat super fast as is the case with most avnrt svts because the avnode is a small area. The way they correct avnrt and most svts is that they burn the tissue on part of the extra pathway that is causing a looping rentry of the electrical circuit keeping it from being able to complete the path. They aren't really eliminating the extra pathway just sort of building a wall of scar tissue to keep any signal from going down that extra path. The problem is, the younger we are the more likely our bodies can heal and regenerate so generally they wait to do ablations until we are older and less likely to regenerate. But considering how active you were it seemed prudent to do the ablation sooner rather than later. That said, I am a little bewildered that the EP did not map the issue when he was doing the ablation. From what I understand there is likely a typical spot that most people have the extra muscle fibers develop but still, every patient is different and it sounds like he may have cut corners to save money possibly not bill your insurance? Not sure why he would not have mapped it out first. It may be a good question to ask him or maybe consider going to a different EP if you have lost faith in the one who did the ablation.
I had avnrt my whole life. It's something you are born with and won't go away without an ablation but for me it was rare as a child and only got active in my late 30s. I had it ablated in my 40s and haven't had an episode since. I had my ablation 9 years ago so maybe things have changed but seems to me you would want to know exactly where it was before you ablate. So it's possible he didn't get the correct spot or it's possible you had multiple spots or extra entry points and he only got the most active and mapping would have showed more spots. Considering how active you were it seems possible. And finally, it's possible he wasn't aggressive enough with the actual ablation. When my EP found the spot he burned once then burned it a second time for good measure to make sure a scar would form.
I'm not sure why you think you might have avrd but from what I read on it, it is a form of rare cardiomyopathy and I would think that would have showed up on an echo so if you had one of those I would think you need not be concerned about that. Being lightheaded and dizzy after exercise could be due to low electrolytes so make sure you drink water and even sports drinks if you sweat a lot during exercise. Also try to make sure you have eaten well. Low blood sugar from not eating might also cause the symptoms you feel after exerting yourself. This said, I know I had issues exercising and pushing myself cardiowise until after I had the ablation done. Not sure why but seems those with svt struggle with high cardio activities.
Well, I do hope you are able to get it under control for good with a second ablation. I wouldn't worry about it being anything else until after you have had that done. Best of luck and do keep us posted. Take care.