cardiac ablation surgery https://medlineplus.gov/ency/article/007368.htm Catheter Ablation medlineplus.gov/ency/article/007368.htm https://medlineplus.gov/ency/article/007368.htm medlineplus.gov/ency/article/007368.htm tried antiarrhythmic medications unsuccessfully radiofrequency ablation medlineplus.gov/ency/article/007368.htm