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. 2013 Sep 1;13(5):185-9.
doi: 10.1016/s0972-6292(16)30672-6. eCollection 2013.

Simultaneous Accessory Pathway and AV Node Mechanical Block

Daniel Garofalo  1 , Alfonso Gomez Gallanti, David Filgueiras Rama, Rafael Peinado Peinado
Affiliations

Simultaneous Accessory Pathway and AV Node Mechanical Block

Daniel Garofalo et al. Indian Pacing Electrophysiol J. .

Abstract

We report a clinical case of a 22-year-old female referred to our institution due to palpitations and preexcitation. Her ECG suggested a right superior paraseptal accessory pathway (AP), which was localised during the electrophysiological study at the superior paraseptal region in close proximity to the His recordings. Reproducible orthodromic reciprocating tachycardia was induced by atrial pacing with extrastimuli. Cryo-mapping performed in the area of earliest atrial activation was not able to terminate the tachycardia. A second attempt, slightly more posterior, caused mechanical block of the AP, which rendered the tachycardia non-inducible. More pressure with the ablation catheter determined a Wenckebach type supra-hisian AV block, which was transient but reproducible. Given this finding no ablation was done. Simultaneous block to the AP and the atrioventricular node has rarely been reported using radiofrequency energy. However, to our knowledge this phenomenon has not been previously reported in large series using cryo-thermal energy.

Keywords: Accessory pathway; Atrioventricular node; Block; Cryoablation; Orthodromic reciprocating tachycardia.

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Figures

Figure 1
Figure 1
Baseline 12-lead ECG at the beginning of the electrophysiology study showing intermittent pre-excitation. A positive/negative QRS in V1 and R>S in lead III suggested a right superior paraseptal location.
Figure 2
Figure 2
Induction of atrio-ventricular reciprocating tachycardia with a single extrastimulus from the atrium. Earliest atrial activation can be seen at the proximal pair of electrodes at the His catheter, which shows continuous activity and near absence of His electrogram. HBEP, HBEM, HBED: His catheter from proximal to distal. ORB: decapolar catheter placed in the coronary sinus. RVA: right ventricular apex catheter.
Figure 3
Figure 3
Wenckebach-type AV block caused by pressure with the ablation catheter, showed at a sweep speed of 67 mm/sec. ABL: ablation catheter. RVA: right ventricular apex catheter.
Figure 4
Figure 4
A His catheter recording confirms a supra-hisian block. Note the absence of a His potential following the atrial activity after the third QRS complex.
See this image and copyright information in PMC

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