Catheter ablation of ventricular ectopy with para‐hisian origin: importance of mapping both sides of the interventricular septum and understanding when to stop ablating

Figures

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  Figure 1. (A) Morphology of the first PVC (QRS duration 148 msec, inferior axis with humps on the inferior leads). (B) Earliest activation is seen at the RV septum above the His‐bundle (preceding the QRS onset by 27 msec). In the position where a His‐bundle potential is registered, the bipolar signal precedes the QRS onset by 25 msec with a slow downstroke slope in the unipolar signal; close above, an earlier bipolar signal with rapid QS on the unipolar and no His‐bundle potential is found. (C) Two multipolar catheters are placed via the femoral vein at the right ventricular apex and at the His‐bundle; a third one is inserted via the internal jugular vein into the coronary sinus. Right (30°, left panel) and left (50°, right panel) anterior oblique radiographic views show the ablation site.

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  Figure 2. (A) Morphology of the second PVC. (B) Earliest activation is seen under the RCC (−46 msec). The activation time is the same on both sides of the interventricular septum, but the unipolar signal has a more rapid downstroke slope of the QS on the left compared to the right side. (C) Radiographic position of the catheters shown in B. Of note, abnormal LV substrate was confined to the inferior wall, and no low amplitude and/or fractionated potentials were seen on the septum.

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  Figure 3. (A) Unsuccessful attempt slightly more apical in the LV (far field His‐bundle on the ablation proximal) despite early local activation time (−42 msec) in the bipolar signal (but late beginning of the QS complex in the unipolar). (B) successful ablation site (−44 msec, low‐voltage His‐bundle on the ablation distal). (C) Immediate disappearing of the PVCs at this position B with inadvertent AH prolongation despite low‐energy application after 60 sec.

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  Figure 4. (A) Last attempt on the RV septum (−46 msec). In SR, on the distal ablation are recorded both atrial and ventricular signals with an His‐bundle potential, while the proximal bipolar shows only an atrial signal without ventricle 11. Despite low energy, fast junctional beats immediately occur. (B) Local activation in the RCC (−20 msec to the onset of the QRS). Disappearance of the PVCs is observed relatively late during application of 35 Watt. (C) Computed tomography scan showing the relationship between the right, the left septum, and the aortic root. (D) 3D Mapping of PVC 2 showing similar activation times on both sides of the interventricular septum.