FBI (Fast Broad Irregular)

Abstract

HomeCirculationVol. 114, No. 24FBI (Fast Broad Irregular) Free AccessReview ArticlePDF/EPUBAboutView PDFView EPUBSections ToolsAdd to favoritesDownload citationsTrack citationsPermissions ShareShare onFacebookTwitterLinked InMendeleyReddit Jump toFree AccessReview ArticlePDF/EPUBFBI (Fast Broad Irregular)A Case for the Secret Service? Sergio Richter, MD and Pedro Brugada, MD, PhD Sergio RichterSergio Richter From the Heart Rhythm Management Institute, Department of Cardiology, Free University of Brussels, Brussels, Belgium. Search for more papers by this author and Pedro BrugadaPedro Brugada From the Heart Rhythm Management Institute, Department of Cardiology, Free University of Brussels, Brussels, Belgium. Search for more papers by this author Originally published12 Dec 2006https://doi.org/10.1161/CIRCULATIONAHA.106.641746Circulation. 2006;114:e638–e639A 34-year-old man without a medical history of cardiac disease presented to our emergency room with fast and irregular palpitations. An instantaneously recorded surface ECG revealed the diagnosis (Figure). The tracing showed an irregular, wide QRS-complex tachycardia with right bundle-branch block, right superior axis deviation, and short RR intervals varying from 160 to 340 ms. The widths of the right bundle-branch block–shaped QRS complexes varied in response to changes in ventricular cycle length. A narrow QRS complex with normal axis was observed (Figure, asterisk), indicating a normally conducted capture beat. Download figureDownload PowerPointTwelve-lead ECG during fast, broad, and irregular (FBI) tachycardia. Preexcited atrial fibrillation with rapid anterograde conduction over a left posterolateral bypass tract is present. Note the normal, narrow QRS complex (asterisk) among the irregularly irregular preexcited ventricular complexes and the varying degrees of preexcitation depending on variation in ventricular cycle length (the concertina phenomenon). The shortest RR interval is 160 ms.This grossly irregular, rapid right bundle-branch block tachycardia represented preexcited atrial fibrillation (AF) with anterograde conduction over a left posterolateral accessory pathway, leading to irregularly irregular preexcited ventricular complexes with varying degrees of preexcitation. The shortest RR interval during preexcited AF was 160 ms, indicating a short anterograde refractory period of the accessory pathway and an increased risk for the development of ventricular fibrillation and sudden death.The differential diagnosis of preexcited AF includes ventricular tachycardia and atrial fibrillation with aberrancy. The presence of an apparent fusion and capture beat could lead one to the diagnosis of ventricular tachycardia, because these findings are considered diagnostic for ventricular tachycardia. Morphologically speaking, the tachycardia is ventricular in origin. Nevertheless, the marked cycle-length variation of more than 100% strongly argues against ventricular tachycardia and instead favors preexcited AF as the underlying arrhythmia mechanism. The right superior axis deviation and the fact that longer RR intervals lead to more fully preexcited QRS complexes compared with shorter RR cycles (the concertina phenomenon) virtually exclude AF with solely aberrant conduction.Preexcited atrial fibrillation with rapid ventricular response reveals a typical electrocardiographic pattern that is often diagnostic at first glance. Because of its characteristic ECG features (fast, broad, and irregular), this tachyarrhythmia has been named FBI tachycardia. This potentially life-threatening clinical condition is obviously a case for the emergency rather than the secret service.DisclosuresNone.FootnotesCorrespondence to Sergio Richter, MD, Heart Rhythm Management Institute, Department of Cardiology, Free University of Brussels, Laarbeeklaan 101, 1090 Brussels, Belgium. E-mail [email protected] Previous Back to top Next FiguresReferencesRelatedDetailsCited By Littmann L, Olson E and Gibbs M (2019) Initial evaluation and management of wide-complex tachycardia: A simplified and practical approach, The American Journal of Emergency Medicine, 10.1016/j.ajem.2019.04.027, Online publication date: 1-Apr-2019. December 12, 2006Vol 114, Issue 24 Advertisement Article InformationMetrics https://doi.org/10.1161/CIRCULATIONAHA.106.641746PMID: 17159067 Originally publishedDecember 12, 2006 PDF download Advertisement SubjectsArrhythmiasElectrophysiology