Pacing, N-Acety Cystein

I have HCM and have had problems with afib, a-flutter, atach. Albations by Andrea Natale, but there were still areas he had not seeled off yet. While in arrhythmia I felt just awful with DHF (ER bound). Then my Dr suggested Fleccanide, despite the antiquated notions that it was too dangerous for HCM patients. It is working right now. However, now that I am back in sinus, I don't feel as well as I did just a few months ago -- my last time in sinus. I noticed I am being paced almost all the time and I still feel symptoms. They lowered my Medtronic pacing threashold to 35bpm but my natural rate would not pick up. They switched modes to at least improve the pacing (rvp? to DDF?), but it has only helped a little. My question is:

1. Can my natural rate come back with time (I still have old Amio in my system, I didn't exercise the last 2 months)? I am on 100mgx2 of Fleccanide. Is that too much? Is there room to cut back on that to restore my natural rate, yet keep in sinus? Or is my avnode permantently out of service because of all the ablations/meds over the years?

2. Do you have suggestions about using the ICD settings to find more comfortable pacing? Remember just 2 months ago, last time I was in sinus, I did not feel this bad, even the times I was being paced, and I know the Virtuoso has varying modes that effect how you are paced.

3. If this is as good as I feel in sinus, can I get help, maybe from Mayo, for improving hydrodynamics for DHF and large LA with hypertrophy in the LV?

Last my Dr suggested acetyl cystein as something that could not hurt, but might help because of its theoretical advantages for reversing LV fibrosis and hypertrophy.

4. Is it benign? Would it suppress the natural rate I am trying to restore? Have you ever heard of this theoretical study/effects?

Please answer at least one if not all 4, off the top of your head, the best you can. It will help me going into my appointments. Thanks

[Cleveland Clinic]

1. Yes it can take time to get your sinus node to recover after being on amiodarone for a long time. Flecanide can suppress the sinus node as well, and it is dangerous in aptients with HCM so I would prefer not to use it unless you have a defibrillator.
2. Possibly an upgrade to a BIV ICD may make you feel better. Anything short of that, maybe only atrial pacing, but I do not know what your av node can conduct to.
3. Not sure about that.
4. I think N acetyl cysteine may have theoretical benefits in a variety of states in which oxygen radicals may play a role, but it has not definitively been shown clinically to improve outcomes in patients with HCM.