How successful is cardiac ablation?

Ablation: Depends on the arrhythmia. For atrial fibrillation, about 80%, for atrial flutter, close to 95%, for ventricular tachycardia, 90+%.

Depends on…: For avnrt and avrt (the latter also called wolf parkinson white) the success rate can be as high as 98%. The same can also be true for typical (right atrial) atrial flutter. Atrial tachycardias in expert hands can be as successful as 85%, even if of a complicated type. Ventricular tachycardias are a much more diverse group, and more info would be needed to give a good answer.