- Case 1 A special case of orthodromic AVRT
- Case 2 AV conduction during pacing
- Case 3 Narrow versus wide QRS
- Case 4 Infra-Hissian complete AV block
- Case 5 Para-Hisian pacing/1
- Case 6 Para-Hisian pacing/2
- Case 7 Para-Hisian pacing/3
- Case 8 Overdrive pacing during SVT/1
- Case 9 Unipolar electrogram morphology
- Case 10 RV pacing during orthodromic AVRT
- Case 11 VBP during orthodromic AVRT
- Case 12 A single VPB during SVT/1
- Case 13 Which wide complex tachycardia?
- Case 14 The wonderful effects of adenosine
- Case 15 Lower common pathway/1
- Case 16 Lower common pathway/2
- Case 17 Atrial tachycardia
- Case 18 Bipolar electrogram morphology
- Case 19 Cavo-tricuspied isthmus block?
- Case 20 Entry block during atrial fibrillation
- Case 21 A Mahaim case
- Case 22 Pacing during IART/1
- Case 23 Pacing the PV after isolation/1
- Case 24 Activation recovery interval
- Case 25 Double fire tachycardia
- Case 26 A single VPB during SVT/2
- Case 27 Sinus rhythm and something
- Case 28 Overdrive pacing during SVT/2
- Case 29 Slow pathway ablation
- Case 30 Is the slow pathway ablated?
- Case 31 Which narrow QRS tachycardia?
- Case 32 Block over a linear ablation line?
- Case 33 Pacing the PV after isolation/2
- Case 34 LAA or LSPV?
- Case 35 A right-sided bypass tract
- Case 36 Orthodromic AVRT
- Case 37 Peri-mitral flutter, or is it?
- Case 38 A single VPB during SVT/3
- Case 39 Mapping the accessory pathway
- Case 40 A ventricular bump during SVT
- Case 41 Atrial tachycardia
- Case 42 PV isolation
- Case 43 RSPV potentials
- Case 44 An interrupted inferior vena cava
- Case 45 Ventricular pacing during SVT
- Case 46 From narrow to wide QRS tachycardia
- Case 47 Where are we within the VT circuit?
- Case 48 Pacing manoeuvre during VT
- Case 49 Mapping the infarct scar
- Case 50 Fractionated electrograms
- Case 51 On the origin of VT
- Case 52 Fascicular VT
- Case 53 An APC during wide-QRS tachycardia
- Case 54 Entraining VT
- Case 55 VT mapping from the coronary sinus
- Case 56 Looking at preexcitation
- Case 57 Where do these VPBs come from?
- Case 58 Looking closely at VPB
- Case 59 Enterpreting entrainment during VT
- Case 60 VT with alternating cycle length
- Case 61 Dormant conduction
- Case 62 2:1 block during SVT
- Case 63 Slow pathway ablation
- Case 64 Entrainment pacing during SVT
- Case 65 Pacing during IART/2
- Case 66 Ablation-resistant PVCs
- Case 67 SVT induction
- Case 68 Residual conduction
- Case 69 Dissociated atrial fibrillation
- Case 70 Catheter bumps can teach
- Case 71 AVNRT subforms
- Case 72 Late far-field in the LAA
- Case 73 Post-MI VT
- Case 74 PV exit block testing
- Case 75 Bundle branch reentrant VT
- Case 76 Slow-fast AVNRT
(p. 10) Narrow versus wide QRS
- (p. 10) Narrow versus wide QRS
, Mattias Duytschaever
, and Haran Burri
Introduction to the case
Case 3 is regarding a 35-year-old woman with a history of recurrent palpitations. She had no prior history of syncope and has a structurally normal heart on echocardiography. A 4-wire electrophysiological study was performed and during an antegrade curve (S1 400ms, S2 260ms), the following tachycardia was induced (Figure 3.1). The VA intervals are outlined on the coronary sinus (CS) channel. During tachycardia, the following phenomenon is observed.
(p. 11) Question
Narrow versus wide QRS during tachycardia
This tracing demonstrates an eccentric atrial activation sequence which would be consistent with a left AT or the presence of a left lateral accessory pathway. There is one diagnostic feature which proves that the left lateral accessory pathway is a critical part of the circuit—there is intermittent LBBB with VA prolongation during the LBBB beats. This phenomenon of VA prolongation during orthodromic tachycardia using an accessory pathway ipsilateral to the bundle branch block was originally described by Coumel. Often it prolongs the tachycardia cycle length (TCL) as the re-entrant wavefront is forced to take a longer route via the contralateral bundle branch (right bundle in this case). However, the cycle length may remain the same despite ipsilateral bundle branch block if the AH interval shortens to compensate (or, in other words, no cycle length prolongation does not exclude an ipsilateral accessory pathway). Hence, it is crucial to measure the VA interval (from the onset of the QRS complex to the earliest atrial electrogram) to make the diagnosis, and not just the TCL.1 VA prolongation by ≥40ms provides strong evidence of a free wall AP in ipsilateral bundle branch block in the absence of a pre-existing underlying fascicular block.
1. Yang Y, Cheng J, Glatter K, Dorostkar P, Modin GW, Scheinman MM. Quantitative effects of functional bundle branch block in patients with atrioventricular reentrant tachycardia. Am J Cardiol 2000; 85: 826–31. (p. 13) Find this resource: