T-wave alternans was closely related to VT in patients with DCM. T-wave alternans is a useful noninvasive test for identifying high risk patients with DCM who have VT.

No abstract

Optimal pace mapping is a good predictor of the appropriate ablation site for idiopathic right ventricular tachycardia (VT) originating from the right ventricular outflow tract (RVOT). We studied the relationship between the RVOT pacing site and QRS morphology in the 12-lead ECG during pacing to find the optimal site more quickly. In 13 patients with idiopathic VT, pacing at 8 sites in the RVOT (free wall, septum, and anterior and posterior regions of upper and lower sites) was performed while 12-lead ECGs were recorded. The R-wave amplitude minus the S-wave amplitude in lead I (RI-SI) and aVF (RavF-SavF) and the transitional zone index (TZI) were compared in the different pacing sites; TZI was defined to examine the transitional zone as a value. The RI-SI was smaller in the anterior region than in the other regions, and the negative RI-SI predicted that the pacing site was in the upper or lower anterior regions. The RavF-SavF was larger in the septum and anterior regions than in the free wall and posterior regions. The TZI was larger in the free wall region than in the septum. From the results, we constructed a flow chart that differentiates the origin of the arrhythmia in the RVOT and a directional guide that indicates the direction from the current mapping site for optimal pace mapping. The results provided an ECG guide for locating the focus of VT originating from the RVOT. These findings may systematically improve the mapping procedure.

No abstract

A 29‐year‐old male who underwent a complete tetralogy of Fallot repair at 2 years of age was referred to our hospital for treatment of sustained ventricular tachycardia (VT). The bipolar voltage map using an electroanatomical mapping system (CARTO, Biosense‐Webster. during sinus rhythm revealed a low voltage area identical to the site of the right ventricular outflow tract (RVOT. patch on the anterior wall of the RVOT. During the tachycardia, the activation wavefront was found to revolve in a counterclockwise manner around the patch in the RVOT. Two radiofrequency catheter ablation (RFCA. sessions creating a line between the patch in the RVOT and pulmonary artery achieved only transient success. He underwent a pulmonary valve replacement and reconstruction of the RVOT with a transannular patch to treat the VT refractory to RFCA and severe pressure gradient in the RVOT. In postoperative electrophysiological study, a low voltage area in the RVOT connected to the pulmonary artery with the patch was observed, and produced conduction block in the reentry circuit of the VT. The patient has been free from any VT recurrence during 6 months of follow up.