title: Sudden QRS morphology change during ventricular pacing in a scar-related isthmus What is the mechanism?
abstract: We present an example of sudden modification in QRS morphology during ventricular pacing inside a scar-related isthmus. This is explained by a "concealed" sudden block in both the orthodromic and antidromic wavefront directions, allowing then the activation to proceed through a now overt antidromic conduction.
authors: University Hospital Rangueil Toulouse, France. Electronic address: mauryjphil@hotmail.com.
authors: Philippe
authors: P
authors: Maury
authors: University Hospital Rangueil Toulouse, France.
authors: Anne
authors: A
authors: Rollin
authors: University Hospital Nancy, France.
authors: Jean-Marc
authors: JM
authors: Sellal
authors: University Hospital Rangueil Toulouse, France.
authors: Alexandre
authors: A
authors: Duparc
authors: University Hospital Rangueil Toulouse, France.
authors: Pierre
authors: P
authors: Mondoly
authors: University Hospital Rangueil Toulouse, France.
authors: Christelle
authors: C
authors: Cardin
authors: University Hospital Nancy, France.
authors: Christian
authors: C
authors: De Chillou
mesh_terms: D000368:Aged; D058406:Cardiac Resynchronization Therapy / Q000379:methods*; D002921:Cicatrix / Q000150:complications / Q000175:diagnosis*; D003937:Diagnosis, Differential; D004562:Electrocardiography / Q000379:methods*; D005260:Female; D006801:Humans; D017682:Myocardial Stunning / Q000150:complications / Q000175:diagnosis*; D017180:Tachycardia, Ventricular / Q000175:diagnosis* / Q000209:etiology / Q000601:surgery; D016896:Treatment Outcome
keywords: Entrainment; Isthmus; Pace-mapping; Reentry circuit; Ventricular tachycardia