Successful cryoablation of an atypical slow-slow atrioventricular nodal reentrant tachycardia utilizing a superior slow pathway

Figures

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  Figure 1. Twelve-lead electrocardiogram obtained during sinus rhythm (A) and paroxysmal supraventricular tachycardia (PSVT) (B). A: Sinus rhythm. The heart rate was 45 beats/min and no delta wave was observed. The PR interval and QRS width were 198 ms and 84 ms, respectively. B: PSVT. The heart rate was 115 beats/min and this tachycardia exhibited a narrow QRS complex (86 ms) and short RP interval. This tachycardia also exhibited a P-wave configuration positive in lead V1 and negative in the inferior leads. C: Ventriculoatrial (VA) conduction followed by burst pacing from the right ventricle (RV) apex (S-S cycle length of 500 ms). The earliest site of the atrial activation was in the His bundle region. The SA interval and local VA interval were 251 ms and 191 ms, respectively. This VA conduction had a decremental property and no other sequences of the retrograde conduction were observed. D: Three-dimensional activation mapping of the anteroseptal right atrium during the ventriculoatrial conduction (EnSite Velocity; Abbott, Plymouth, MN). The earliest atrial activation site (white area) was on the interatrial septum slightly superior to the His bundle region (yellow tag). The diameter of…

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  Figure 2. A: An atrial echo beat was induced without an AH jump by triple atrial extrastimulation. The sequence of the retrograde conduction was identical to that during the right ventricle (RV) apex stimulation and this retrograde conduction was followed by that through the antegrade fast pathway. B: Intracardiac recording by a multipolar electrode during a short RP tachycardia (the clinical tachycardia). This tachycardia was only induced with triple atrial extrastimulation after the jump in the AH interval under the administration of high-dose isoproterenol. The atrial activation during the tachycardia was earlier in the His bundle region than in the coronary sinus, and the atrial activation sequence was identical during the tachycardia and ventricular stimulation from the RV apex (Figure 1C), which was suggestive of antegrade conduction via the typical slow pathway and retrograde conduction via the superior slow pathway. AH = the interval from the atrium to the His bundle potential; CS = coronary sinus potential; HBE = His bundle electrogram; HRA = high right atrium; S = stimulation.

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  Figure 3. A: Left anterior oblique (LAO) view (45°) of the multipolar electrode catheter position during the electrophysiology study. B: LAO view (45°) of the multipolar electrode catheter and the ablation catheter position. Before the cryoablation, the multipolar electrode catheter in the His bundle region was exchanged for the ablation catheter. C: Intracardiac recording from a multipolar electrode catheter during sinus rhythm before the cryoablation. A slow potential was recorded from the distal tip of the ablation catheter at the site of the typical slow pathway region. The electrogram’s atrial-to-ventricular ratio at that point was 1:3. D: Intracardiac recording from a multipolar electrode during the clinical paroxysmal supraventricular tachycardia (PSVT). During this tachycardia, the ventricular potential preceded the atrial potential. ABL = ablation catheter; CS = coronary sinus potential; HBE = His-bundle potential; HRA = high right atrium; RV = right ventricle; S = stimulation; Uni = unipolar potential.