(230) Calcium Channel Blockers Versus Adenosine for Treatment of SVT in an Emergency Setting

Introduction: Adenosine is recommended as a first-line agent for the treatment of stable supraventricular tachycardia (SVT) by the AHA/ACCP/HRS guidelines. Recent evidence suggests that non-dihydropyridine calcium channel blockers (CCB) may be reasonable alternatives, although use has been associated with adverse events. The difference between agents in healthcare burden is also not well-defined. The goal of our study is to compare efficacy, adverse events and healthcare burden associated with the use of adenosine versus CCB for stable SVT in the emergency setting.

Methods: A retrospective chart review was performed of patients of any age who presented to an academic medical center emergency department with SVT. Outcome measures included reversion to normal sinus rhythm (NSR), occurrence of adverse events, length of stay (LOS), disposition, doses required, and pertinent vital signs.

Results: 101 encounters were identified across 89 unique patients, who were predominantly female (64%) and white (75.3%) with a mean age of 44.9±22.3 years and a mean BMI of 27.4±8.4 kg/m^2. SVT was treated with only adenosine (adeno only) in 69 encounters (68.3%), only diltiazem (CCB only) in 21 (20.8%), and a combination of the two (adeno/CCB) in 11 (10.9%). 52 encounters (51.5%) involved the use of vagal maneuvers. There were significant differences between the adeno only and adeno/CCB groups, including median LOS (3.63 vs 10.85 hours, respectively, p=.017), rate of hospital admission (37.7% vs 81.8%, p=.024), and rate of conversion to NSR (92.8% vs 45.5%, p=.0016 as well as between the CCB only and adeno/CCB groups in rate of hospital admission (28.6% vs 81.8%, p=.024). There were no statistically significant differences in adverse event rates, NSR conversion rates, median LOS, admission rates, or median post-dose heart rates between the adeno only and CCB only groups.

Conclusions: We found no clinical difference in using CCB instead of adenosine in the treatment of SVT in an emergency setting. There were significantly lower rates of conversion to NSR, LOS, and admission rates in patients receiving both adenosine and CCB. This may be a result of inherently more refractory SVT in these patients prompting attempted use of two agents. Based on our results, CCB is a reasonable first-line agent for stable SVT.