A case of preexcitation syndrome showing atypical atrioventricular nodal reentrant tachycardia and orthodromic atrioventricular reciprocating tachycardia with a bystander concealed nodoventricular/nodofascicular pathway

Figures

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  Figure 1. Responses to His-refractory ventricular extrastimulation (VES) in supraventricular tachycardia (SVT)-1a and SVT-1b. A: His-refractory VES for SVT-1a reset the tachycardia with delay of subsequent His and atrial electrograms. B: Diagram of SVT-1a. C: His-refractory VES for SVT-1b reset the tachycardia with delay of subsequent His and atrial electrograms. D: Earlier His-refractory VES for SVT-1b terminated the tachycardia without atrial capture. E: Diagram of SVT-1b. AP = accessory pathway; AVN = atrioventricular node; AVNRT = atrioventricular nodal reentrant tachycardia; CS = coronary sinus; FP = fast pathway; HRA = high right atrium; LCP = lower common pathway; NF = nodofascicular; NV = nodoventricular; RBB = right bundle branch; RV = right ventricle; RVA = right ventricle apex; SP = slow pathway.

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  Figure 2. Responses to His-refractory ventricular extrastimulation (VES) in supraventricular tachycardia (SVT)-2a. A: In SVT-2a, VES at the timing of the His electrogram did not reset the tachycardia. B: Earlier His-refractory VES (His 14 ms) rest the tachycardia with advancement. C: Further earlier His-refractory VES (His 24 ms) terminated tachycardia without atrial capture. D: Diagram of SVT-2a. AVRT = atrioventricular reciprocating tachycardia; other abbreviations as in Figure 1.

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  Figure 3. Responses to His-refractory ventricular extrastimulation (VES) in supraventricular tachycardia (SVT)-2b. A: In SVT-2b, VES at the timing of the His electrogram reset the tachycardia with delay of subsequent His. Although atrial electrograms immediately after VES were not reset, next atrial electrograms were delayed. B: Earlier His-refractory VES (His 20 ms) advanced the atrial electrograms immediately after the stimulation, but subsequent His electrogram was delayed owing to decremental conduction of the antegrade slow pathway (SP). C: Further earlier His-refractory VES (His 30 ms) advanced the atrial electrograms immediately after stimulation, leading to termination of the tachycardia. D: Diagram of SVT-2b. AVRT = atrioventricular reciprocating tachycardia; other abbreviations as in Figure 1.