Successful ablation of ventricular tachycardia in which resected infundibular septum served as a critical isthmus in a patient with double-outlet right ventricle after Rastelli surgery

Figures

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  Figure 1. Postoperative status. A: 3D CT findings in the anterior view without the RV. An IR-P was sewn from the base of the IVS to the subaortic muscular tissue. B and C: 3D CT and LGE magnetic resonance images showing extensive LGE in the ligated PA and LVOT (magenta triangle). D: The native PA is ligated, and the PA stump is included in the LVOT. The ligated PA trunk and aorta are separated by an infundibular septum. 3D CT = 3-dimensional computed tomography; AO = aorta; IR-P = intraventricular routing patch; IVS = interventricular septum; LA = left atrium; LCA = left coronary artery; LGE = late gadolinium enhancement; LV = left ventricle; LVOT = left ventricular outflow tract; MV = mitral valve; PA = pulmonary artery; RA = right atrium; RV = right ventricle; RCA = right coronary artery.

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  Figure 2. Electrocardiography using overdrive pacing during ventricular tachycardia. A and B: Twelve-lead electrocardiogram performed during ventricular tachycardia (TCL, 337 ms) showed a left bundle branch block pattern with a left upper axis and a transition zone at V4-5. C: On the aortic side of the infundibular septum, the PPI coincided with the TCL, whereas the stimulus–QRS interval to TCL interval ratio was 17% (exit site). D: In the native pulmonary artery, the PPI and TCL coincided, with a stimulus–QRS interval to TCL interval ratio of 43% (central isthmus). ABL = ablation; IVS = interventricular septum; LV = left ventricle; NPA = native pulmonary artery; PPI = postpacing interval; RV = right ventricle; TCL = tachycardia cycle length; TV = tricuspid valve.

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  Figure 3. Successful ablation site (A), prepotential and scheme (B), and local activation mapping (C) of ventricular tachycardia. The local potential on the aortic side of the infundibular septum (exit site) preceded the QRS onset by 58 ms. However, radiofrequency application was ineffective. In the central isthmus of the native pulmonary artery, which is closer to the IS, a mid-diastolic potential was observed that preceded QRS onset by 145 ms, and the VT was terminated after radiofrequency application at the same site. ABL = ablation; AO = aorta; IS = infundibular septum; LV = left ventricle; LVOT = left ventricular outflow tract; NPA = native pulmonary artery; PA = pulmonary artery; Patch = intraventricular rerouting patch; PPI = postpacing interval; RV = right ventricle; RVOT = right ventricular outflow tract; TV = tricuspid valve; VIF = ventriculoinfundibular fold; VSD = ventricular septal defect; VT = ventricular tachycardia; VTCL = ventricular tachycardia cycle length.