IIb B-R Oral digoxin or amiodarone may be reasonable for ongoing treatment of AVNRT in patients who are not candidates for, or prefer not to undergo, catheter ablation.99,115 See Online Data and 10. One small study randomized patients with unspecified PSVT to digoxin (0.375 mg/day), propranolol (240 mg/day), or verapamil (480 mg/ day), with 1 week of placebo washout.99 Episodes and duration of PSVT (ascertained by diary and weekly 24-h Holter) were largely similar, and all 3 medications were well tolerated.99 However, the dose of digoxin used was higher than that commonly used in clinical practice today. Amiodarone is effective in suppressing AVNRT during outpatient follow-up.115 Given the potential adverse effects of digoxin and amiodarone, these agents are generally reserved as third-line therapy for patients who are unresponsive to, or are not candidates for, beta blockers, diltiazem, verapamil, flecainide, or propafenone. IIb C-LD Self-administered ( pill-in-the-pocket ) acute doses of oral beta blockers, diltiazem, or verapamil may be reasonable for ongoing management in patients with infrequent, well-tolerated episodes of AVNRT.241,242 See Online Data Supplement 9. Two studies have demonstrated success with the combination of diltiazem and propranolol as a pill-in-the-pocket approach to acutely terminate PSVT caused by AVNRT, but the overall safety of self-administration of these medications remains unclear because episodes of syncope were observed.241,242 If oral therapy with empiric beta blockers, diltiazem, or verapamil fails to terminate the tachyarrhythmia, patients should seek medical attention. Figure 10. Acute treatment of suspected focal atrial tachycardia. Colors correspond to Class of Recommendation in Table 1; drugs listed alphabetically. *For rhythms that break or recur spontane- ously, synchronized cardioversion is not appropriate. IV indicates intravenous. 6. 