Alternative Treatment Options for Atrioventricular-Nodal-Reentry Tachycardia: An Emergency Medicine Review

Background: Atrioventricular-nodal-reentry tachycardia (AVNRT) is a form of supraventricular tachycardia (SVT) that is relatively common in the emergency department (ED). It is rarely indicative of underlying electrical or structural pathology. Objective: This review evaluates the literature and controversies concerning treatment of AVNRT in the ED. Discussion: For treatment of narrow-complex tachycardia, Advanced Cardiovascular Life Support guidelines recommend the use of vagal maneuvers, followed by adenosine. Recent literature suggests that nondihydropyridine calcium channel blockers, such as verapamil and diltiazem, may be as effective as adenosine, without the negative short-term side effects. Multiple studies have demonstrated that although adenosine is rapid acting, there is no statistically significant difference in conversion rate between adenosine and calcium channel blockers. Both medications result in a conversion rate above 90%, but there are significantly more minor adverse effects, such as flushing or chest discomfort, with adenosine. Calcium channel blockers are a viable option for treatment for AVNRT, especially in refractory states. Beta-blockers have been evaluated but should not be used routinely due to lower efficacy. AVNRT is the most common tachydysrhythmia in pregnancy, and vagal maneuvers and adenosine are first line. Electrical cardioversion should be utilized for hemodynamically unstable patients. Most patients with AVNRT may be discharged with appropriate follow-up. Conclusion: Several studies demonstrate that nondihydropyridine calcium channels (verapamil and diltiazem) are equally as efficacious as adenosine in converting AVNRT to sinus rhythm, without the negative (albeit short-lived) side effects. If given over 20 min, the risk for hypotension is low.