Electrocardiographic Differentiation Of Fascicular Ventricular Tachycardia From Atrial Flutter With Right Bundle Branch Block Aberrant Conduction

Introduction: Atrial fibrillation often converts to atrial flutter (AFL) during management with class IC antiarrhythmic drugs. Differentiation of AFL with right bundle branch block (RBBB) pattern from fascicular ventricular tachycardia (VT) is difficult when R/S ratio in V6 is below 1.0. We sought to investigate the electrocardiographic criterion for distinguishing these arrhythmias. Method: We studied 32 consecutive patients (mean age 40.7±15.8 years, 24 male) who underwent successful catheter ablation for left posterior fascicular VT and 30 consecutive patients (mean age 57.0±17.8 years, 22 male) who were diagnosed with AFL with RBBB aberrancy where R/S raito in V6 was u003c 1.0. AFL with RBBB pattern was diagnosed based on the following criteria: 1) AV block during adenosine infusion or treadmill test 2) Induced by electrophysiology study 3) Interrogation of cardiac implantable electronic devices The rS/QRS ratio was defined as the ratio of QRS waveform durations as measured from the QRS onset to nadir of ...