Obviously I realise it won't stop AF but the worry was that the persistent tachycardia and af were damaging my heart. I am 61 with full time active job. Initially it worked well but now I can barely walk again after a pacemaker check and tweak three weeks ago. has anyone had to have numerous tweaks before it works properly? I am so very disappointed at the moment as I am as bad as I was before it was properly diagnosed.