Ablation for SVT

My 17 year old daughter was discovered to have SVT about a year ago during a routine exam. She as never had any outward symptoms and in fact the SVT ceases all together during excersise. No enlargement or injury to the heart is evident at this time. Drug therapy made no difference. She recently had a mapping and attempted ablation, which, after 5 hours, was unsucessful. I was told the area in question is either deep in the heart muscle or behind the pulmonary artery and is, in either case, hard to reach. She is being sent to a second specialist.

I am wondering if, considering a lack of symptoms and apparent damage to the heart muscle, the procedure should in fact be attempted once again. What is the long term prognosis for these kids? Do the risks outweigh the benefits in the long-term? Is there another procedure to reach these "hard to get to" areas inside the heart?

[Jeffrey R Boris, M.D.]

Dear LInz Mom,

Supraventricular tachycardia (SVT) is due to an extra electrical connection (pathway) between the top and the bottom of the heart that isn't supposed to be there.  She was born with it, so she has always had it.  Overall, it is a nuisance, especially when young.  However, the likelihood of spontaneous resolution is essentially zero.  And, as we age, the heart is not as tolerant of either episodes of SVT or ablation.  Therefore, it is not unreasonable to try to get this done at this age.  With regard to the difficulty in reaching the extra pathway, there are numerous newer techniques that can be used.  In good experienced hands, it may certainly be possible to reach and to ablate the pathway.  There are other, much more invasive methods of exposing the pathway, but then it becomes a weighing of the risks vs. benefits.  Catheter-based electrophysiology study with radiofrequency ablation is quite low risk, and so is probably worth attempting again in this case.