Successful bipolar radiofrequency catheter ablation in a case of scar-related ventricular tachycardia with intramural critical isthmus in basal posterior right ventricle identified by coherent mapping

Figures

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  Figure 1. A: Twelve-lead electrocardiogram during sinus rhythm and the ventricular tachycardias (VTs) observed during procedures. B: The endocardial and epicardial bipolar voltage maps showed an extensive low-voltage area with abnormal electrograms in the basal posterior right ventricle, which extended to epicardial interventricular septum and basal posterior left ventricle. CL = cycle length; PA = posteroanterior; TV = tricuspid valve.

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  Figure 2. A: Arrows indicating conduction velocity vectors on coherent maps obtained during ventricular tachycardia (VT) 5 showed epicardial activation converging in an area in the basal posterior right ventricle and endocardial activation diverging from the same area, suggesting the presence of an intramural slow conducting isthmus of the VT circuit (zigzag arrow). B: Entrainment pacing at the earliest activation site (blue star) showed concealed fusion with VT5 and a postpacing interval that matched the cycle length of VT5. CAU = caudal; RAO = right anterior oblique.

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  Figure 3. A, B: Bipolar radiofrequency (RF) catheter ablation was performed between the distal electrodes of 2 irrigated ablation (ABL) catheters, with the active electrode in the right ventricle (RV) endocardium (ABLEndo) and the ground electrode in the RV epicardium (ABLEpi), as shown by fluoroscopy and 3D electroanatomic mapping. C: The timing of the ABLEndo electrogram coincided with QRS onset of ventricular tachycardia (VT) 5, whereas the ABLEpi electrogram preceded the QRS onset by 70 ms. D: The target VT terminated in 2.4 seconds after start of the bipolar RF application delivered with a maximum power setting of 30 W for 45 seconds. CS = coronary sinus; LAO = left anterior oblique; RAO = right anterior oblique.