Intracardiac Echocardiography to Assist Anatomical Isthmus Ablation in Repaired Tetralogy of Fallot Patients With Ventricular Tachycardia

Figures

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  Figure 1. Workflow for Intracardiac Echocardiography in Repaired Tetralogy of Fallot (A) Views from the right atrium are used to create right ventricular geometry and mark the location of the tricuspid annulus. (B) The intracardiac echocardiography (ICE) catheter is advanced into the right ventricle (RV) with anterior tilt to create additional RV geometry and mark the defibrillator lead position. (C) The best view in our experience is with posterior tilt in the RV looking through the right ventricular outflow tract (RVOT) into the pulmonary artery. The location of the pulmonary annulus is marked. (D to F) The location and extent of the ventricular septal defect patch are defined by ICE, using small degrees of rotation and tilt to optimize the image. (G and H) Finally, the RVOT/transannular patch location is defined. Enlarged and annotated views are provided in Supplemental Figures 1 to 8 and Supplemental Video 1, Supplemental Video 2, Supplemental Video 3, Supplemental Video 4, Supplemental Video 5.

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  Figure 2. Integration of Structures Defined on Intracardiac Echocardiography Into Electroanatomic Maps (A) A bipolar voltage map in RAO and LAO projections using cut-offs of 0.5 to 1.5 mV. There is extensive low voltage in the right ventricular outflow tract without any clear definition of where the surgical patches sit. (B to D) Intracardiac echocardiography (ICE) is used to collect anatomy of the ventricular septal defect patch (VSDP) (brown) and the right ventricular outflow tract patch (RVOTP) (green). (E, F) The anatomy of surgical patches can be superimposed on the voltage map of the ventricle using the CartoSound module. This can then be used to plan ablation of 1 or more anatomical isthmuses. AP = anteroposterior; LAO = left anterior oblique; PA = posteroanterior; RAO = right anterior oblique.

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  Figure 3. Patient Outcomes A flow diagram showing the outcomes of each individual patient undergoing VT ablation in the study. The number of patients at each step is in red. ∗The index procedure for these 2 patients preceded the study inclusion period. Cryo = surgical cryoablation; ICE = intracardiac echocardiography; RF = radiofrequency ablation; TOF = tetralogy of Fallot; VT = ventricular tachycardia.

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  Central illustration. Use of Intracardiac Echocardiography to Help Identify the Location and Ablation of the Anatomical Isthmus Sustaining Ventricular Tachycardia in Repaired Tetralogy of Fallot

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  Figure 4. Variation in Ventricular Septal Defect Patch Location and Isthmus 3 (A to C) The variation in the location and extent of the ventricular septal defect patch (VSDP) is demonstrated in 3 patients. The boundaries of the patch as defined by intracardiac echocardiography are shown in transparent white for ease of differentiation. The anatomy of the patch cannot be determined by voltage mapping alone (bipolar voltage cut-offs; red: <0.5 mV, purple: >1.5 mV), as demonstrated by extensive low voltage in the right ventricular outflow tract. VSDP = ventricular septal defect patch.