Early Experience with High-density Electroanatomical Mapping Using the Rhythmia™ Mapping System in Congenital and Pediatric Heart Disease

Figures

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  Figure 1:. The case of a patient (patient 2) with hypoplastic left heart syndrome post–lateral Fontan. Images show electrograms, isochronic activation mapping (red indicating the earliest activation and purple indicating the latest scaled in milliseconds), and ablation sites (red points) of a tricuspid isthmus–dependent atrial flutter within the RA [upper six images, right anterior oblique (RAO) and left anterior oblique (LAO) projections] and a focal, automatic tachycardia in the lateral Fontan (bottom three images, RAO and LAO projections). The electrogram ablation catheter tracing signal is well before the atrial and the coronary sinus tracings, and the unipolar catheter tracing shows a Q-wave, all suggesting placement at the origin of the atrial tachycardia.

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  Figure 2:. The case of a patient (patient 3) with hypoplastic left heart syndrome post–fenestrated Fontan who developed an atrial flutter. The voltage maps [top two images, RAO and LAO projections] of the SVC, RA, IVC, and left pulmonary artery seen here show a scar below the sinus node and low-voltage area down to the IVC at the anterolateral RA. The isochronic activation maps (bottom two images) show the RA in an RAO projection in sinus rhythm after treatment, with no wave progression through ablation lesions (red points). The scale for the voltage maps is from 0.01 (red) to 20 mV (purple). The isochronic activation maps indicate the earliest activation with red color and the latest activation with purple color in milliseconds.

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  Figure 3:. The case of a patient (patient 4) with D-transposition of the great vessels post–Mustard procedure. Image shows electrograms, isochronic activation mapping, and ablation lesions (red points) within the IVC, SVC, and systemic venous Mustard baffle from the RAO and LAO projections. An atrial tachycardia with earliest local activation at the anterosuperior aspect of the baffle was ablated. The electrogram shows earliest activation in the coronary sinus leads. A Q-wave is seen in the unipolar lead, suggesting that this is the site of exit for the focal atrial tachycardia. The isochronic activation maps indicate the earliest activation with red color and the latest activation with purple color in milliseconds.

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  Figure 4:. The case of a patient (patient 5) with D-transposition of the great vessels post–Mustard procedure. Mapped territory consists of the IVC, systemic venous baffle, left (systemic venous) atrium, and right (pulmonary venous) atria. The top two images show isochronic activation maps and ablation of an atrial tachycardia with the region of earliest activation on the superior margin of the patient’s systemic venous baffle. The electrogram shows a signal close to but not at this ablation site. The bottom two images show mapping and ablation (red points) of a subsequently induced atrial flutter in the pulmonary venous atrium. The isochronic activation maps indicate the earliest activation with red and the latest activation with purple in milliseconds.