The efficacy of amiodarone has been reported only in pediatric patients.389,390 Digoxin has not been well established as chronic therapy for junctional tachycardia. A related rhythm, nonparoxysmal junctional tachycar- dia (more commonly known as accelerated AV junctional rhythm), is far more common in adults than paroxysmal junctional tachycardia. The mechanism of nonparoxysmal junctional tachycardia is associated with automaticity or trig- gered activity. It occurs at a slower rate (70 bpm to 130 bpm) and is often due to digoxin toxicity391 or myocardial infarc- Treatment of this rhythm centers on addressing the underlying condition. In addition, there is some evidence that beta blockers,394 intravenous adenosine, or verapamil395 can terminate an accelerated junctional arrhythmia. A tran- sient junction rhythm may be seen after slow-pathway abla- tion for AVNRT.396 8.1. Acute Treatment: Recommendations Recommendations for Acute Treatment of Junctional Tachycardia COR LOE Recommendations IIa C-LD 1. Intravenous beta blockers are reasonable for acute treatment in patients with symptomatic junctional tachycardia.388 See Online Data Supplement 19. In a series studying junctional tachycardia in adult patients, beta-blocker therapy specifically intravenous propranolol was found to be modestly effective in terminating and/or reducing the incidence of tachycardia.388 IIa C-LD 2. Intravenous diltiazem, procainamide, or verapamil is reasonable for acute treatment in patients with junctional tachycardia.397 See Online Data Supplement 19. There may be a limited role for intravenous diltiazem, procainamide, or verapamil in patients in whom beta blockers are ineffective. The literature supports the use of intravenous verapamil, alone or in combination with procainamide; less is known about diltiazem The addition of procainamide to propranolol may be more effective than propranolol monotherapy.388 Figure 14. Acute treatment of orthodromic AVRT. Colors cor- respond to Class of Recommendation in Table 1; drugs listed alphabetically. *For rhythms that break or recur spontaneously, synchronized cardioversion is not appropriate. 