Coumel's sign reversed: What is the mechanism?

Abstract

A patient presented with documented narrow QRS tachycardia. During electrophysiological study, he has orthodromic reciprocating tachycardia with atrial activation consistent with left free wall accessory pathway. With induction of tachycardia, beats with LBBB morphology have shorter cycle length than those with narrow QRS. What is the mechanism?

Keywords

• Reverse Coumel
• Dual AV nodal Physiology
• CL increase with narrow QRS