Inappropriate sinus tachycardia, ablation/pacemaker need advice

[katie4593]

Hello all a very frustrating journey this past year has been, I apologize for the long post but the journey has been long. I'm a 23 year old female. Back in December I felt very short of breath & dizzy, I went to the emergency room where my heart rate was 168, they treated me & said I suffered from SVT. I also want to mention since I was 17 o was diagnosed with high blood pressure(is around 180/110 with medication) everything was ruled out & deemed genetic as my dad got diagnosed at a young age as well. Therefore I am seen regularly by cardiologist. Over the years my heart rates been increasing & since the hospital stated I had SVT my cardiologist sent me to an electrophysiologist who did an EP study in December. He could not induce this so called SVT; but due to reoccurring symptoms such as dizziness, shortness of breath, nausea he implanted a loop recorder to see what was going on. I had been taking bystolic 20 mg, after my episode in December they added cardizem 240 mg. the symptoms never seemed to resolve but I tried to deal with it. Fast forward to last week I felt short of breath & dizzy, I went to the ED & was sustaining in the 160's. They started me on IV cardizem & admitted me for 4 days. My cardiologist then sent me back to EP Doctor who looked into my implanted loop recorder, the reason the first EP study failed is because that first hospital misdiagnosed me. I actually suffer from inappropriate sinus tachycardia not SVT. Although my heart rate goes to 180 it's sinus rhythm! My heart rate hangs around 120 but almost every day goes to 160 for no reason, just at rest. This IST has caused me activity intolerance, I can't work out because I get so dizzy & sob. I just saw the electrophysiologist who added Ivabradine 5 mg twice a day, in addition to my bystolic 20 mg & cardizem 240mg. He wants to see me in a week & see if my heart rate improves. If not there is an option for sinus node ablation but he said there is a risk he would need to implant a pacemaker & would feel terrible as I'm only 23. With IST have any of you had good results with Ivabradine? medications have not helped me at all. Did you have an ablation? Did you need a pacemaker? it seems like there's not much on the internet about this

[researcher09]

Katie, sorry to hear of your IST problems.  I don't know very much about IST other than reading what's available on the HRS guidelines for treating IST.  The most important thing I gathered from the articles is that the trigger(s) are located close to the sinus node and that is the reason for the risk of heart block and potentially the need for a pacemaker in the worst case.  Because the trigger(s) are close to the sinus node, precise and high density mapping is needed and the ablation catheter needs to be stable in order for the ablation to be successful without damaging the sinus node.  For that reason, cryo or magnetic tip catheters are often used because they will attach the catheter tip to a spot precisely even if the heart is pumping.  So, I think the thing you need to ask your EP is how he plans to achieve high density mapping and stable precise contact to minimize the chance of you getting complete heart block and requiring a pacemaker implant as a result.  If he is not well trained in doing the procedure using the tools I mentioned, then your best chance of beating your IST would be to find a center that has the tools AND the experience to ablate successfully.

[katie4593]

One typo, that's my blood pressure "without" medication. Apologies!