A very unusual wide QRS tachycardia: VT or SVT?

ABSTRACT

INTRODUCTION: A 13 old girl presented with recurrent wide QRS tachycardia since she was 4. METHODS: An electrophysiologic study was performed. RESULTS: The electrophysiologic study showed that QRS complexes identical to those of the tachycardia could be elicited with premature atrial extrastimuli but with a shorter atrioventricular (AV) delay when the QRS was wide compared with narrow QRS complexes. The tachycardia was ablated at 9 o'clock on the tricuspid annulus demonstrating the presence of an atriofascicular fiber. CONCLUSION: We believe that this atypical behavior can be explained by AV nodal like longitudinal dissociation of a slowly conducting accessory pathway.