Dear DL,
I doubt the tachycardia is due to the pacemaker placement. More likely the sotalol has stabilized some of the arrhythmias and allowed this one to sustain. 80mg of Sotalol is a very low dose and I would favor increasing this as tolerated. If this fails or if you are having side-effects I would suggest another ablation attempt at a center with some of the newer high tech mapping equipment. There are very few arrhythmias coming from the atrium that we are not able to cure with ablation these days.