The transition of the tachycardia from narrow to wide by a spontaneous atrial premature beat: What is the mechanism?

Abstract

The transition of the tachycardia from narrow to wide by a spontaneous atrial premature contraction causing a long‐short sequence and right bundle branch block

Transition from two wide to a narrow QRS complex tachycardia: What is the mechanism of tachycardia and transition?

“…In current tracings, the transition shows that change to a slow AV nodal pathway also resets the tachycardia. This suggests the presence of multiple fast/retrograde AV nodal pathways, 21 and these transitions could be related to the second slow pathway 22–24 . Therefore, the multiple forms of induced tachycardias with both RBBB and LBBB morphologies favor atypical AVNRT 6,17,18 …”

“…This suggests the presence of multiple fast/retrograde AV nodal pathways, 21 and these transitions could be related to the second slow pathway. [22][23][24] Therefore, the multiple forms of induced tachycardias with both RBBB and LBBB morphologies favor atypical AVNRT. 6,17,18 It would be only speculative to make a concise correlation with anatomy since the AH change over a slow pathway might be both due to functional decremental conduction or perhaps more than one distinct anatomical slow pathway.…”

A wide QRS tachycardia with the short and long ventriculoatrial interval in the presence of an atriofascicular pathway: What is the mechanism?

“…The differential diagnosis of a regular WCT with 1:1 AV association includes (1) orthodromic atrioventricular reentrant tachycardia (AVRT) with aberrancy; (2) atrial flutter or atrial tachycardia (AT) with ventricular pre-excitation; (3) antidromic AVRT with retrograde conduction through bundle branch-His-AV node axis; (4) pre-excited tachycardia due to pathway-to-pathway (duodromic) conduction (5) atrioventricular nodal reentrant tachycardia (AVNRT) with bystander AP conduction; (6) AVRT with bystander activation of ventricles using another pathway; (7) ventricular tachycardia (VT) or bundle brunch reentry tachycardia; (8) junctional tachycardia with aberrancy or fasciculoventricular connection; and (9) antidromic AF, nodofascicular or nodoventricular reentrant tachycardia. [1][2][3][4][5][6][7][8][9][10][11][12] Advancement of ventricular activation by an APC at a time when the septal atrium (proximal coronary sinus) has been already (retrogradely) depolarized followed by resetting of the tachycardia in patients with decremental conducting AF (Figure 1) is a helpful maneuver to prove AP existence and participation in the circuit, 5,13,14 and also rules out a myocardial VT. It is also important in WCT to identify accurately the retrograde limb of the circuit, often requiring placement of VPC (Figure 2) in addition to APC to define the antegrade limb during the tachycardia.…”

“…The differential diagnosis of a regular WCT with 1:1 AV association includes (1) orthodromic atrioventricular reentrant tachycardia (AVRT) with aberrancy; (2) atrial flutter or atrial tachycardia (AT) with ventricular pre‐excitation; (3) antidromic AVRT with retrograde conduction through bundle branch–His–AV node axis; (4) pre‐excited tachycardia due to pathway‐to‐pathway (duodromic) conduction (5) atrioventricular nodal reentrant tachycardia (AVNRT) with bystander AP conduction; (6) AVRT with bystander activation of ventricles using another pathway; (7) ventricular tachycardia (VT) or bundle brunch reentry tachycardia; (8) junctional tachycardia with aberrancy or fasciculoventricular connection; and (9) antidromic AF, nodofascicular or nodoventricular reentrant tachycardia 1–12 …”