A narrow QRS complex during a left bundle branch block morphology wide QRS tachycardia: A clue for manifest or bystander involvement of nodofascicular pathway?

A Wide QRS Complex Tachycardia with Variation of Ventriculoatrial Interval: What is the Mechanism?

The differential diagnosis for wide complex tachycardia includes all causes of narrow complex tachycardia with bundle branch block, all causes of narrow complex tachycardia with antegrade pre-excitation, ventricular tachycardia, and antidromic and other pre-excited reciprocating tachycardias. The variation in a specific intracardiac interval that causes a subsequent change in the tachycardia cycle length or another intracardiac interval can be diagnostic in these arrhythmias.

Widening of the QRS complex during the wide complex tachycardia: What is the mechanism?

Tachycardia-induced tachycardia, or so-called double tachycardia, appears to be a relatively rare condition. This article is protected by copyright. All rights reserved.

Simultaneous narrow and wide QRS complex tachycardia: Misdiagnosis or Missed diagnosis?

Tachycardia-induced tachycardia, or so-called double tachycardia, appears to be a relatively rare condition. Regardless of the mechanism, this case illustrates the importance of assessing the response to multiple different pacing maneuvers in determining the mechanism of narrow and wide QRS complex tachycardias, rather than relying upon a single maneuver, even one that is believed to be diagnostic. This article is protected by copyright. All rights reserved.

Transition from Two Wide to A Narrow QRS Complex Tachycardia: What is the mechanism of tachycardia and transition?

Spontaneous transition from one tachycardia to another tachycardia poses a challenge to the electrophysiologists and most likely occurs by multiple mechanisms. This article is protected by copyright. All rights reserved.

A Wide QRS Tachycardia with Three Distinct Left Bundle Branch Block Morphologies in a Patient with Sinus Rhythm with Left Bundle Branch Block: What Is the Mechanism?

The differential diagnosis for a wide complex tachycardia includes all causes of supraventricular tachycardia (SVT) with bundle branch block or all causes of SVT with antegrade pre-excitation by bystander involvement of any accessory pathways, myocardial or bundle brunch ventricular tachycardia, and antidromic (atriofascicular or nodofascicular/nodoventricular) and other pre-excited reciprocating tachycardias. We present a case of wide complex QRS tachycardia with a left bundle branch block QRS morphology.

Termination, Advancement, and Delaying Responses to His Synchronous Premature Ventricular Contractions During Narrow QRS Tachycardia: What Are the Possible Mechanisms?

The differential diagnosis of a regular, narrow QRS, long-R-P tachycardia includes atypical atrioventricular nodal reentry tachycardia, atrial tachycardia, and atrioventricular reentry tachycardia via a slowly conducting accessory pathway with decremental conduction properties. Almost all described diagnostic maneuvers in the electrophysiology laboratory have exceptions to their primary interpretation. The usual proviso is that the observation must be reproducible.