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Objectives: We performed noninvasive identification of post-infarction sustained monomorphic ventricular tachycardia (SMVT)–related slow conduction channels (CC) by contrast-enhanced magnetic resonance imaging (ceMRI). Background: Conduction channels identified by voltage mapping are the critical isthmuses of most SMVT. We hypothesized that CC are formed by heterogeneous tissue (HT) within the scar that can be detected by ceMRI. Methods: We studied 18 consecutive VT patients (SMVT group) and 18 patients matched for age, sex, infarct location, and left ventricular ejection fraction (control group). We used ceMRI to quantify the infarct size and differentiate it into scar core and HT based on signal-intensity (SI) thresholds (>3 SD and 2 to 3 SD greater than remote normal myocardium, respectively). Consecutive left ventricle slices were analyzed to determine the presence of continuous corridors of HT (channels) in the scar. In the SMVT group, color-coded shells displaying ceMRI subendocardial SI were generated (3-dimensional SI mapping) and compared with endocardial voltage maps. Results: No differences were observed between the 2 groups in myocardial, necrotic, or heterogeneous mass. The HT channels were more frequently observed in the SMVT group (88%) than in the control group (33%, p < 0.001). In the SMVT group, voltage mapping identified 26 CC in 17 of 18 patients. All CC corresponded, in location and orientation, to a similar channel detected by 3-dimensional SI mapping; 15 CC were related to 15 VT critical isthmuses. Conclusions: SMVT substrate can be identified by ceMRI scar heterogeneity analysis. This information could help identify patients at risk of VT and facilitate VT ablation. [ABSTRACT FROM AUTHOR]

An abstract of the paper "3D Visualization of Myocardial Substrate Using Delayed Enhancement MRI for Pre-Planning and Guidance of Ablation Procedures of Ventricular Tachycardia," by Jose L. Rubio-Guivernau and colleagues is presented.

This study was conducted to assess the usefulness of transesophageal echocardiography (TEE) as a guide in the percutaneous transcatheter occlusion of paravalvular defects and in subsequent follow-up. In 27 consecutive patients with mitral paravalvular leaks with significant regurgitation considered to be poor surgical candidates who were treated with percutaneous closure of the defects, TEE was performed before and during the procedure. If the device was successfully positioned, a reevaluation was made 1 month later. Events occurring during the procedure and 1-month follow-up were recorded. The device was correctly positioned in 17 of the patients (63%). TEE enabled the detection of complications (intraprosthetic insufficiencies due to passing the guide through the prosthesis, blockade of the prosthesis, etc.). It also confirmed the correct canalization of the leak with the catheter and the position of the device. In 8 patients (47% of patients with successful implantation), the degree of regurgitation was substantially reduced after 1 month. In conclusion, TEE is a fundamental technique when considering the percutaneous treatment of paravalvular leaks in patients with high surgical risk. It provides essential information on the characteristics of the dehiscence during implantation and follow-up. [Copyright &y& Elsevier]