Comparison of Vagal Maneuvers and Antiarrhythmics on Adult Patients Presenting with Supraventricular Tachycardias (SVT)

INTRODUCTION: SVT is a well-known and potentially life-threatening arrhythmia, with vagal maneuvers and/or antiarrhythmic drugs often attempted for first-line conversion. The purpose of this clinical review is to analyze the relative effectiveness and success rates of these specific maneuvers and medications. METHODS: The following PubMed database search was performed:“((vagal maneuver*) OR (valsalva)) AND (pharmacologic) ((medication) OR (medical therapy) OR (adenosine) OR (beta blocker*) OR (calcium channel blocker*) OR (anti-arrhythmic*) OR (anti arrhythmic*) OR (antiarrhythmic)) AND ((SVT) OR (supraventricular tachycardia))”. Filters were then applied and article titles/abstracts reviewed, resulting in a final selection of five articles for review. RESULTS:. The most effective vagal maneuver found across two studies was modified valsava, with one meta-analysis resulting >40% SVT conversion . Adenosine consistently performed with a higher success rate (~90%) compared to vagal maneuvers (20-40%) in termination of stable SVT, however the latter were still recommended to be attempted first due to their noninvasive and convenient nature. Novel intranasal agents like etrapamil have recently shown efficacy in initial RCT’s for acute termination of SVT, and have the potential for further study. DISCUSSION: Modified valsalva consistently showed the most favorable results, however only 2-3 attempts should be made prior to deferring to administration of adenosine, with multiple administrations and increased dosing preferred prior to second-line alternatives. Unstable SVT requires synchronized cardioversion.