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

Wide complex tachycardia with negative precordial concordance: All that glitters is not gold

“…A WCT may result from supraventricular tachycardia (SVT) with bundle branch block (pre‐existing or tachycardia‐related), SVT with atrioventricular conduction over an accessory pathway (AP), or ventricular tachycardia (VT) 1–8 . Double tachycardia is uncommon but should always be in differential diagnosis in the presence of CL or QRS morphology change.…”

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 …”

Multiple wide QRS tachycardias in the same individual with ischemic cardiomyopathy

“…The classic teaching over the years has been that all cases of WCT are to be treated as VT until proven otherwise, particularly in patients with structural heart disease [1][2][3][4][5][6][7][8][9][10][11][12][13] ; however, the alternative diagnosis is also possible. 1,2 While the NCT in Figure 1 was most probably supraventricular tachycardia (SVT), the WCT was the diagnostic dilemma.…”