Diagnosis and management of patients who present with narrow complex tachycardia in the emergency department.

Introduction: While narrow complex tachycardia (NCT) is a common presentation to the emergency department (ED), little is known about its incidence in the ED or about emergency physician expertise in its diagnosis and management. We sought to compare cases of NCT due to primary arrhythmias to those with a rapid heart rate secondary to a medical issue, as well as to determine the accuracy of ED physician diagnosis and appropriateness of treatment.

Methods: We conducted a health records review at a large academic hospital ED staffed by 95 physicians and included consecutive adult patients over 7 months (2020-2021) with NCT (heart rate ≥ 130 bpm and QRS < 120 ms). Cases were reviewed for accuracy of ECG diagnosis and for correctness of treatment as per guidelines by an adjudication committee.

Results: We identified 310 ED visits (0.8% of all ED visits), mean age 65.1 years, 52.6% female. Primary arrhythmias accounted for 54.8%. ED physicians correctly interpreted 86.6% of ECGs. The most common arrhythmias and accuracy of ED physician ECG interpretation were atrial fibrillation 44.5% (95.1%), sinus tachycardia 24.2% (90.5%), atrial flutter 15.8% (61.5%), and supraventricular tachycardia (SVT) 12.9% (81.6%). Treatments were judged optimal in 96.5% of primary NCT and 99.3% in secondary NCT. Treatments were suboptimal for failure to reduce heart rate < 100 bpm prior to discharge in 2.1% of primary cases and failure to treat underlying cause in 0.7% of secondary cases.

Conclusion: NCT was found in 0.8% of all ED visits, with more being primary NCT. ED physicians correctly interpreted 86.6% of ECGs but had difficulty differentiating atrial flutter and SVT. They implemented appropriate care in most cases but sometimes failed to adequately control heart rate or to treat the underlying condition, suggesting opportunities to improve care of NCT in the ED.