Ventricular arrhythmias associated with left ventricular noncompaction: Electrophysiologic characteristics, mapping, and ablation.

Background: Left ventricular noncompaction (LVNC) is a primary cardiomyopathy that can present with recurrent ventricular arrhythmias (VAs). Data on the benefit of catheter ablation of VAs in LVNC are lacking.

Objective: The purpose of this study was to describe the electrophysiologic features and outcomes of catheter ablation of VAs in LVNC.

The Influence of Mitral Annuloplasty on Left Ventricular Flow Dynamics.

Background: Mitral valve (MV) repair using annuloplasty rings is the preferred method of treatment for MV regurgitation, but the impact of annuloplasty ring placement on left ventricular intraventricular flow has not been studied.

Methods: Annuloplasty rings of varying sizes were placed in 5 healthy sheep (intercommissural ring sizes were 24, 26, 28, 30, and 32 mm), and three-dimensional phase contrast magnetic resonance imaging (4D flow MRI) was performed before and 1 week after ring placement.

Results: Normal diastolic flow consisted of diastolic intraventricular vortices that naturally unwound during systole.

Stages: sub-Fourier dynamic shim updating using nonlinear magnetic field phase preparation.

Heterogeneity of the static magnetic field in magnetic resonance imaging may cause image artifacts and degradation in image quality. The field heterogeneity can be reduced by dynamically adjusting shim fields or dynamic shim updating, in which magnetic field homogeneity is optimized for each tomographic slice to improve image quality. A limitation of this approach is that a new magnetic field can be applied only once for each slice, otherwise image quality would improve somewhere to its detriment elsewhere in the slice.