Successful catheter cryoablation for premature ventricular contractions originating from the para‐Hisian region

Figures

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  Figure 1. The 12‐lead superficial ECG obtained in the outpatient department suggests that the PVCs originated near the His bundle in the right ventricular septum. ECG, electrocardiography; PVC, premature ventricular contractions

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  Figure 2. The earliest activation site by three‐dimensional mapping and cryoablation sites. Green tags indicate the points where the His potential was recorded with a hexapolar diagnostic catheter and/or a cryocatheter. A1: The activation map initially created before the first application of cryoenergy. Black arrow indicates the earliest activation site of PVCs. A2: Applications shown by red tags were unsuccessful. B1: Map modified using newly acquired potentials superimposed on the initially created map. The earliest activation site shifted to a higher position (white arrow). B2: Two blue tags indicate the sites at which cryoablation was clearly effective. Only a 5‐mm gap exists between the His potential and the cryocatheter tip. The last two application sites are indicated by blue tags. PVC, premature ventricular contractions

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  Figure 3. The precedence of the distal bipolar electrogram from the rise of QRS complexes and the R‐wave duration during the clinical PVCs at the earliest activation site. The precedence at the last two cryoablation sites is significantly greater than that at the first ablation site. In addition, the R‐wave durations at the last two ablation sites are significantly longer and possess higher frequencies. Black and yellow dotted lines represent the rise, and terminal point of the R‐wave recorded by the distal bipolar electrogram, respectively. The red dotted line represents the rise of the QRS complex recorded by the surface ECG. D, Duration; ECG, electrocardiography; P, precedence; PVC, premature ventricular contractions

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  Figure 4. A: Comparison between clinical PVCs and the pace map recorded just prior to the first application of cryoenergy. A good pace map was obtained. B: Comparison between clinical PVCs and the pace map recorded after the fifth cryoablation attempt. The precordial transition zone shifted leftward. The sixth attempt had no effect on clinical PVC morphology. ABL, ablation catheter; Clin PVC, clinical premature ventricular contraction; PM, pace mapping

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  Figure 5. Pacing with the maximum output at the earliest activation site just before the sixth attempt. The first beat became narrow, which suggested that the pacing captured the His bundle