204 | Chapter 10 Figure 1. Inclusion flowchart IVF patients included in a large national registry from three tertiary centers were included. Abbreviations: CMR = cardiac magnetic resonance, IVF = idiopathic ventricular fibrillation. CMR imaging All included subjects underwent CMR examination on a clinical 1.5T or 3T MR scanner using electrocardiographic gating and a phased array cardiac receiver coil according to standardized cardiac protocols.22 Breath-hold balanced steady‐state free‐precession (bSSFP) cine images covering both the ventricles and atria were acquired (4-chamber long-axis view, 2- and 3-chamber long-axis LV views and multi-slice full coverage of the LV in short axis orientation). The voxel size of the cine sequences used was dependent on the local clinical scan protocol and was typically around 1.5 x 1.5 x 5-8 mm3. In addition, late gadolinium enhancement (LGE) imaging was performed at least 10 minutes after intravenous administration of a gadoliniumbased contrast agent in identical views. LGE imaging was not performed in control subjects. Ventricular metrics and ejection fraction (EF) were measured in a standardized way using semi-automated contour tracing software.23 Ventricular end-diastolic volumes were indexed for body surface area (EDVi). Patients with major LGE (sufficient for a specific diagnosis) were not included in the IVF registry, while patients with minor LGE of uncertain pathogenicity were included in this study. The LGE images were re-evaluated for any myocardial fibrosis in the left ventricle and papillary muscles by an experienced cardiac radiologist. Mild insertion fibrosis was deemed insignificant for this study. Two blinded observers analyzed CMR images for presence and longitudinal distance of MAD and MVP. Longitudinal MAD distance was measured on all three long-axis cine views from the left atrial wall mitral valve leaflet junction to the top of the left ventricular wall at end-systole. Presence of MAD was defined as a longitudinal displacement of >1 mm (Figure
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