Catheter Ablation for Tachycardia

Factual Questions
1

I have recently been diagnosed with tachycardia, and have a catheter ablation procedure scheduled to (I hope) solve this problem.

My cardiologist’s initial diagnosis was supraventricular tachycardia (SVT) based upon ecg readings obtained from an event monitor. He referred me to an electrophysiologist, who believes it to be right ventricular outflow tract ventricular tachycardia (RVOT-VT) instead.

As I understand it, with SVT, the tachycardia (fast heart rate) is caused because there is a re-entry of the sinus node’s basic signal to beat, causing the atrium to contract again more quickly than it is supposed to. If the electrophysiologist can then pinpoint where the path of this re-entered signal is, he can then just ablate the path (burn it out), and the problem is solved.

So, I felt that I understood the mechanism behind SVT reasonably well. Now that they think it is RVOT-VT, though, I have not been able to come up with a clear understanding of exactly where the problem is coming from. From what I’ve read, RVOT-VT is not a re-entry problem — but I haven’t been able to come up with an explanation of what the mechanism of the problem is.

So, that’s my question: What is the mechanism behind RVOT-VT? Just what is it they’re going to ablate?

Thanks if any of you can shed some light on this. I’d also be interested in hearing if any of you have had this procedure done (which I realize is more of an IMHO question, but I wanted the factual part of this showing up in GQ.)

(For the record, I am otherwise very healthy; they’ve confirmed via stress ecg and echocardiogram that my heart is structurally sound.)

2

Wow. Wayyyy in over my head here, but does any of this help?

3

I was diagnosed with SVT five years ago. Since then I have met about half a dozen other people who have also had it. Tachycardias are the result of a “short circuit” of sorts in the electric system of the heart; a connection is made at a particular juncture where connections usually aren’t made. The ablation procedure is used as a way to burn off the extra connective nerve that is causing the short circuit to occur. It is the most invasive option for treatment. There are drugs (verapamil (commercially sold as Kalan) which are about 50% effective in controlling the effects in people) simply not treating the condition is an option too. Some people learn to control it using the valsalva method (baring down), and one person I’ve met actually stood on her head. For some people the symptoms are fairly minor. My SVT would cause my heart to race at about 210-2140 beats per minute. I never had any blackouts, but definitely a head rush. I could function farily well when an episode would occur, but if they lasted for more than 10 minutes it would be very annoying. If it’s more than a passing annoyance for you (i.e. you find it IMPOSSIBLE to function) you should consider treating the condition.

One thing to consider is your age. Tachycardia is likely to stay with you for your entire life (unless you get ablation). If there is any history of heart disease in your family, you might consider ablation more closely. Tachycardia can aggravate other heart conditions (heart murmurs, clogged arteries, etc.). Also, if you are young and you think that at some point in your life you will want to have the ablation, do it as soon as possible. The last thing you want to do is go in when your 75 because the condition has become to unbearable when you could have taken care of it when you were younger. It is rough to have any surgery done, but you’re more likely to bounce back quickly from it when you are young than when you are old. That said, there are documented cases where tachycardia just went away on its own. This is fairly rare though. Another thing to consider is your health plan. If ablation is covered under your current health plan, it might not be on your next. Some insurance companies will look at tachycardia as a pre-existing condition when you switch to them and not cover the costs of the “elective surgery”, etc.

When I weighed all the considerations for myself, I found that ablation was going to be the best thing for me. My SVT was pretty annoying as I could never predict when an episode would occur. I am the only person I know that has had the procedure done… and I had to have it done twice!!! The first time they went in there, the didn’t burn it off the connection entirely. I ended up getting symptoms again after about a month and a year later, after getting pretty mad at my cardiologist, went in again. This time they did five burns instead of one in order to make sure they got the problem nipped in the bud. Unfortunately they also pierced the pericardia at the end of the procedure which can be a very dangerous thing, but healed up okay for me. They said that my case were the worst combinations of complications they’d seen. I’m sure your cardiologist has told you about all the risks involved (they’re fairly minimal), but it definitely was not fun being on the receiving end of those risks. For example, even though the success rate for ablation on my particular tachycardiawas in the 70% to 90% range, I was one of the lucky few for whom it didn’t work. Also, that reminds me that the procedures are slightly different for different kinds of tachycardia. Usually they aren’t exactly sure what you have until they go in there. Once inside the heart, they have the ability to speed up the heart rate and slow it down. It’s really very strange, because you’re awake at the time and they’ll tell you, “okay, now we’re going to speed up your heart” and that’s exactly what they do. Once they know exactly where the juncture is happening, they’ll be able to stimulate the tachycardia. This is how they supposedly make sure that they get rid of the connection. First they stimulate an episode. Then they stop it. Do a burn. Then they try to stimulate it again. If they can’t get an episode going, they consider it taken care of. In my case, it appears that the connection healed back on itself. Just my luck, I’m afraid.

I’m happy to report now that I’m 100% free of SVT. Occassionally it will feel like I’m about to go into an episode (you know what that feels like, I’m sure), but then it won’t happen. It’s a real nice thing to not have to have this annoyance in my life. I would say, for me, it was worth it, even though I had to have the procedure done twice and they had their pericardia-accident. I’m sort of a strange success story, in that sense. My cardiologist was basically so embarassed by the end that he said if the symptoms returned he would refer me to a different doctor.

If you decide you want ablation: MAKE SURE YOU TRUST YOUR CARDIOLOGIST. Ablation is a very delicate procedure. Some doctors specialize in it and their success rates are much higher. Other doctors aren’t as good at it. Ask your doctor how many (s)he’s done, what the success rates have been, etc. Also, if you are still unsure, get a second opinion. This is a major operation we’re talking about here, complete with IVs, bladder catheters (that was the worst part of the experience for me), and all manner of different kinds of drugs that will put you into altered states. Although there won’t be any large external wounds left and it’s as minimally invasive as possible, there are always the chances of problems (the doctors should go over that with you AS WELL AS a third party nurse who doesn’t have a vested interest in whether the surgery gets done or not so you’re CERTAIN of the risks involved).

So, if this is a major problem for you, I would definitely consider the procedure. Feel free to contact me if you have any more questions. Good luck.

4

I had this very same disease, but it was diagnosed with AV-node re-entry tachycardia. When I was operated on, they discovered that instead of having the “normal” one AV-node, or even the abnormal two that they believed I had, in fact I carried three. They ablated the one they believed to be causing the problem, leaving the main one to stay plus the third smallest and hypothetically the weakest one, not believing that it would continue to cause a problem. I still have minimal episodes, but they don’t affect me as much.
The prodecure itself was very easy, with only catheder wounds on my left shoulder and both my inner thighs. I was required to stay overnight however. I was very pleased with the procedure and I’m glad I had it done, the alternative being a lifetime of Lanoxin tablets. I find it strange that JS Princeton was awake during his/her procedure, I was not. While I do not have your specific version of tachycardia, I hope that my post was a little helpful.

5

Thanks very much for your research, DDG, and your experiences, JS Princeton and ladyfoxfyre. I was especially reassured to hear that not only had you undergone the procedure once, JS P, but that you would then be willing to go back again and try it a second time when the first time didn’t entirely solve the problem.

I’m currently taking verapamil, but am not happy with the prospect of taking drugs the rest of my life. I’ve also been told to keep my heart rate down to 130 beats per minute or so when exercising, which is just unacceptably low for me to tolerate as a limit for a long time. I’m dealing with it now, unhappily, until my ablation takes place, but not liking it. I have to drop back my normal level of intensity when taking kickboxing classes and during other exercises, and it really takes away from my enjoyment and benefits received from the exercise.

My family physician also has SVT, which he is leaving untreated. I asked him about the possibility of using valsalva techniques. We discussed a few, but he also said that standing on his head was what worked best for him. That was when we thought my diagnosis was SVT. When I spoke with my electrophysiologist after he had changed my diagnosis to RVOT-VT about the possibility of trying valsalva techniques, he said that he didn’t think that they would be of much use for RVOT-VT because my problem is not a re-entrant problem, but more of a reaction to adrenaline. In any case, I’m so drugged up right now that I haven’t had a major attack since then which would give me the opportunity to try it out.

I would consider leaving this untreated, but due to my reactions, I don’t think that would be safe. I have my attacks only during and after exercise. I can’t really predict when one will happen, and I have had a couple of them begin while driving home from a workout. Since my most troubling sympton is the fact that I sometimes feel as if I were just about to pass out momentarily, (near syncope), I feel it’s dangerous for me to leave it untreated and then drive when I could potentially have an attack which could result in me actually passing out behind the wheel.

I’m relatively young (41) and healthy, and I just find the thought of being on drugs and restricting my ability to exercise for the rest of my life to be unacceptable. In any case, since my cardiologist would like to have an electrophysiology study performed on me anyhow, just in order to confirm the diagnosis of where the problem is coming from, it just seems that since the invasive part of the procedure needs to be done anyhow, I might as well take advantage of the opportunity to try to get rid of the problem for good.

ladyfoxfyre: I’ve also been told that I will be sedated, but conscious (although a lot of people end up napping through much of it.) He said that at the time of the actual burn, he will put me under, however, as the burning sensation is uncomfortable. (As I understand it, I shouldn’t be able to feel most of the catheterization because there aren’t any nerves in the involved tissue. I guess the heat from the ablation process may register in adjacent areas.)

Thanks very much for sharing your experiences with me. I may be bugging you with a few more questions, if you don’t mind. I also found a very detailed personal account of someone’s ablation experience here.

I still haven’t quite figured out what the mechanism behind RVOT-VT vs. the re-entrant types of tachycardia, however. If anyone else has any info (or other experiences with ablation), I’d still be very interested.

6

IANACardiologist, although I’m pretending to be one this month.

In a normal heart rhythm, the conduction starts at the SA node, the passes through the atria, the AV node, and the ventricles. In reentrant VTach, also known as “plain old VTach”, some of that conduction winds around and makes it back into the atrium and “re-enters” the circuit, messing up that nice steady sinus rhythm.

Your heart, on the other hand, has a small separatist group way down around the outflow tract of the right ventricle that is fed up with the oppressive regime of the SA node, and it decides to take up arms and try to originate heartbeats on its own. These aren’t as strong and focused as the SA node pulses, but they’re strong enough to get a decent beat out of the ventricles, so your ventricles are beating with the pulses they’re getting from two sides. Viola, we have ventricular tachycardia.

So all your cardiologist has to do is find that focus of Little Heart Fibers that Could and ablate them, and you’ll be back in a nice happy sinus rhythm.

That’s a fairly simplified version, and it may make no sense at all–I’m post-call. :slight_smile:

Dr. J

7

Aha — so it’s a case of automaticity run amok?

Apparently that little bunch of disgruntled ventricular separatists is fairly effective — my ecg was showing that they were firing off as many as 11 to 13 beats at a time, giving me a heart rate of up to 255 bpm. Interestingly, when I first went in to my family doctor to complain about this, I felt that my heart rate was SLOWER than usual. When I checked my pulse at my carotid, I was feeling fewer beats per minute than I would typically expect at a given exertion level. I was feeling something along the lines of "beat, beat, beat…BEAT, beat, beat…). He explained the situation was that I was actually having tachycardia, but since there’s no blood for the ventricles to move if the atria haven’t contracted, the extra beats wouldn’t be noticeable at the carotid pulse.

Thanks for your input, DoctorJ. I’m actually learning quite a lot about how my heart works now. (I would rather be learning this about someone ELSE’s heart, however.)

But now I can’t get the image of a bunch of little Pancho Villa-type heart cells, complete with belts of bullets, out of my mind. I’m just hoping the electrophysiologists can find the little buggers and blast them into oblivion.

8

I was seriously drugged up both operations and fell asleep a few times. I do remember the actual burns. For me, there was no sensation at all. If they hadn’t told me that they were doing the burns, I wouldn’t have known. It could have been the happy drugs they put me on, I’m not sure. In some sense I was pleased not to go under because that makes the procedure that much more involved. Just being heavily sedated seems like a better option to me than going under, from an anesthesiological point of view. But then, IANAA (I am not an anesthesiologist).

9

I was happy to hear that I’ll just be sedated, and not fully unconscious. I’m not a big fan of unconciousness.

Did you stay overnight after the procedures? (I’m assuming they kept you in a while when they messed up your pericardium.) How quickly did you recover? I’m trying to figure out how many days I should expect to stay out of work, and when I’ll be able to get back to my old workout schedule.

10

For the first procedure I went home that very day. Within three days, I was able to walk around. They recommended no strenuous activity for two to three weeks, but I began strenuous exercise about a week and a half later.

The second procedure, because of the pericardium piercing, required an overnight stay so they could moniter my condition. I went home late the next morning. Ironically, that one I was able to walk around a day later. They were a bit more cautious and really told me not to go back to exercise for two weeks, and then go lightly for two more weeks after that in order to stave off any internal bleeding in the heart.