In a trial of 122 patients randomized to dofetilide, propafenone, or placebo, the probability of remaining free of SVT after 6 months of treatment was 50% for dofetilide, 54% for propafenone, and 6% for placebo, with P<0.001 for either dofetilide or propafenone compared with placebo.107 Because of the potential for proarrhythmia, dofetilide should be reserved for patients who are not candidates for catheter ablation and for whom beta blockers, diltiazem, flecainide, verapamil, or propafenone are ineffective or cannot be prescribed. IIb C-LD Oral amiodarone may be considered for ongoing management in patients with symptomatic SVT who are not candidates for, or prefer not to undergo, catheter ablation and in whom beta blockers, diltiazem, dofetilide, flecainide, propafenone, sotalol, or verapamil are ineffective or contraindicated.115 See Online Data Supplement 2. Evidence for amiodarone for the ongoing management of SVT is limited. The drug was evaluated in a small retrospective study and was found to be effective in suppressing AVNRT during outpatient follow-up.115 Amiodarone is a second-line agent for patients who are not able to take beta blockers, diltiazem, dofetilide, flecainide, propafenone, sotalol, or verapamil given the toxicity and side effects that may develop with long-term amiodarone therapy. IIb C-LD Oral digoxin may be reasonable for ongoing management in patients with symptomatic SVT without pre-excitation who are not candidates for, or prefer not to undergo, catheter ablation.99 See Online Data Supplement 2. Evidence for the use of digoxin is limited. 