title: Narrow QRS Tachycardia with Transition: What Is the Mechanism?
abstract: A 50-year-old woman underwent radiofrequency catheter ablation of narrow QRS tachycardia that was terminated with intravenous adenosine. Twelve-lead electrocardiogram was normal during sinus rhythm. The electrophysiological study showed normal atriohisian and hisioventricular intervals during sinus rhythm. Atrial burst pacing reproducibly induced two narrow QRS tachycardias. Figure 1 shows spontaneous switch of tachycardia 1 to tachycardia 2. What are the likely mechanisms of the tachycardia and the transition?
authors.affiliation: Department of Cardiology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Thiruvananthapuram, Kerala, India.
authors.forename: Krishna Kumar
authors.initials: KK
authors.lastname: Mohanan Nair
authors.affiliation: Department of Cardiology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Thiruvananthapuram, Kerala, India. kknnamboodiri@gmail.com.
authors.forename: Narayanan
authors.initials: N
authors.lastname: Namboodiri
authors.affiliation: Department of Cardiology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Thiruvananthapuram, Kerala, India.
authors.forename: Bharatraj
authors.initials: B
authors.lastname: Banavalikar
authors.affiliation: Department of Cardiology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Thiruvananthapuram, Kerala, India.
authors.forename: Sonali
authors.initials: S
authors.lastname: Inamdar
authors.affiliation: Department of Cardiology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Thiruvananthapuram, Kerala, India.
authors.forename: Ajitkumar
authors.initials: A
authors.lastname: Valaparambil
authors.affiliation: Department of Cardiology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Thiruvananthapuram, Kerala, India.
authors.forename: Anees
authors.initials: A
authors.lastname: Thajudeen
authors.affiliation: Department of Cardiology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Thiruvananthapuram, Kerala, India.
authors.forename: Jaganmohan
authors.initials: J
authors.lastname: Tharakan
mesh_terms: D017115:Catheter Ablation; D003937:Diagnosis, Differential; D018450:Disease Progression; D004562:Electrocardiography / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D013611:Tachycardia, Atrioventricular Nodal Reentry / Q000175:diagnosis* / Q000601:surgery*; D017180:Tachycardia, Ventricular / Q000175:diagnosis* / Q000601:surgery*; D016896:Treatment Outcome
keywords: AV nodal reentry; AV reentry; transition