What is the after effect of ablation of the heart due to a palpitation?

Improvement maybe. If the procedure is successful, the palpitations will not recur. Of course, if the procedure is not a success, the symptoms will recur. Then there are compkications such as stroke, tamponade (bleeding into the sac around the heart), and injury to blood vessels which may cause bleeding and may require surgical repair.
Good. Ablation has excellent results after svt ablation and good results after afib ablation. However some patients may have the arrhythmia and palpitations for a few months until the "scar" heals.