Correction on SVTs during pregnancy

When my daughter was twelve years old she was diagnosed with supraventricular tachycardia. When the episodes occur her heart rate can be 200 beats per minute or more.  However the SVTs have been controlled very well with medication.  She is twenty one now and graduated from college, married and wants to have a child.  She does not want to have catheter ablation. We have read that SVTs can increase during a pregnancy and I wondered if taking the medication during a pregnancy would be harmful to the baby.  Thank you.

[Cleveland Clinic]

There aren't any good studies out there that have looked at this for obvious reasons.  (nobody would want to part of such a study).  However, we have used all kinds of medications in patients in whom the SVT's get more frequent in pregnancy (this is common) and there really haven't been any teratogenic effects reported.  We usually start with beta blockers and as long they work can keep them on board during pregnancy without any problems.  If the arrhythmia breaks through we then consider starting a stronger medication such as a sodium channel blocker.  The latter is safe but I would not use it in the first trimester of the pregnancy unless absolutely necessary.  The safest way in my opinion would be to have the ablation done prior to the pregnancy and not have to worry about it at all.  This is a very common procedure and the success rate may be as high as 98%.