Electroanatomic Mapping Clues for Distinguishing a Breakthrough Site from the True Focal Source: Beware of a Big Focus.

Figures

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  Figure 1:. Surface 12-lead electrocardiogram during runs of clinical tachycardia.

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  Figure 2:. A: Right atrial activation map during tachycardia. The red pin marks the site of earliest activation within the right atrium. B: Map highlighting the extent of right atrial tissue depolarized within the initial 10 ms of activation (area, ~3.8 cm2).

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  Figure 3:. A: Left atrial activation map with the earliest site located in the posterior right superior pulmonary vein (RSPV). The area activated in the first 10 ms (~2.1 cm2) is shown. B: Intracardiac electrograms at the successful ablation site in the RSPV, demonstrating a sharp near-field potential (−33 ms to P-wave onset) with a QS unipolar morphology.

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  Figure 4:. Merged anatomical map showing the location of the successful ablation lesion in the right superior pulmonary vein (red marker) relative to right atrial structures.