We do not know what causes IST (inappropriate sinus tachycardia). The more symptomatic cases may be helped by ablation. It is always possible for it to return at a different focus or part of your sinus node. Recovery of your old IST would be highly unusual years after the ablation.
I cannot say it would not return -- I just have no way of knowing. Sorry I cannot be more definitive.
I wonder if the IST development after your pregnancy had anything to do with the sudden change in your blood volume levels after the birth? Just a thought.
Hi Kad--thank you for responding to my post. The cardiologist on duty when I had my daughter did feel that the fast heart rate was caused by the change in blood volume. He felt that by eating and drinking normally, that I would improve in a few days, but I did not. But maybe blood volume was the trigger. I have struggled for 4 years now wondering what caused the IST. My ablations successfully contolled it, but I worry so much that it will come back again if I have another baby. Do you have IST? I am really looking for others who have it who I can discuss these issues with. It can be frustrating as no one seems to have many definitive answers about IST.
I did have IST for a little over a year. My rates were always at about 130-140, with rare episodes below 100. The doctors were very concerned that my heart would become enlarged with the constant tachycardia, so they attempted several SA node ablations. I had three ablations done over about a years time. Eventually they did work, but they ended up ablating a little to much of the sinus node and my heart rate dropped profoundly to 30-40. So they ended up putting in a single chamber atrial pacemaker. I've had that in for a little over a year and the IST came back once since I've had it in and they, of course, ablated again and so far so good-nothing has come back and I'm dependent on my pacemaker about 100% of the time, but a least the tachycardia is gone(knock on wood). It was extremely frustrating for me because like you said nobody knows what brings this on and it seems like they just don't have a lot of answers about it. I am otherwise a very young and healthy woman. I really hope they can figure out a better way to treat it one day. They loaded me up with medications to try to treat it, but it wasn't really very effective and I hated the way the meds made me feel(very, vey tired). I hope everything turns out ok for you with your next pregnancy. I haven't had my first child yet, I'm sure it will be an adventure! I would give you my e-mail address, but I don't think it would be safe to do that on public forum.
I forgot to ask you something. It seems like 50's is kind of low for your heart rate. Do you feel good at that rate? Just curious.
Hi KAD. Yes, having my heartrate in the 50's is a bit low, but other than the occasional PVCs and bigeminy, I feel very good. My heartrate comes up easily with activity, and I don't have any problems with dizziness, so my EP feels that the low rate is ok. I'd really like to chat with you more about eveything. My email address is ***@****. Please feel free to contact me. I'd love to have someone to talk to who understands what it is like to have these issues!