During the ablation, the doctor will need to provoke the arrhythmia, I can understand the reason,
in your case, you would need
to withhold. I would follow the Doctor's advice, if he/she did not say to taper, I would not do so.
Concerning abrupt discontinuation of Beta Blockers, the following.
"Ischemic Heart Disease: Following abrupt cessation of therapy with certain beta-blocking agents, exacerbations of angina pectoris and, in some cases, myocardial infarction have occurred.