How often is multifocal atrial tachycardia mistaken for atrial fibrillation in the emergency department?

OBJECTIVE

Multifocal atrial tachycardia (MAT), characterized by an irregularly irregular rhythm, is often regarded as a clinical imitator of atrial fibrillation (AF). We aimed to evaluate the prevalence of MAT misclassification as AF in the emergency department (ED) setting.

METHODS

A retrospective analysis of 1828 ECGs from patients discharged with AF diagnoses over five years. All tracings were independently reviewed by three blinded cardiologists.

RESULTS

MAT was identified in one case (0.05 %). Other misclassifications included atrial flutter (7.9 %), supraventricular tachyarrhythmias (1.6 %), and sinus rhythm with conduction disturbances, artifacts, or ectopy (1.0 %).

CONCLUSIONS

Misdiagnosis of MAT as AF in the ED is rare. However, other diagnostic errors remain relatively common, underscoring the need for careful rhythm evaluation.