Right Ventricular Functional Abnormalities in ARVC | 35 B) The left ventricular (LV) global longitudinal strain (GLS) was calculated in a 16-segment LV model.22-24 RV free wall longitudinal strain was calculated as the averaged peak systolic strain from 3 RV free wall segments. All measurements were performed by a single observer blinded to clinical outcome, who was newly trained in both RV deformation imaging techniques and not involved in the initial development of the methods. Intra- and inter-observer variability of deformation imaging parameters was assessed by reanalysing 20 echocardiographic studies in both the Utrecht and Oslo database. (Supplementary material) Figure 1. Echocardiographic deformation imaging of the RV RV deformation pattern recognition of the basal segment and RV mechanical dispersion performed on an RV focused 4-chamber view. Panel A: Based on predefined criteria, a division into 3 different deformation patterns is identified.6 Type I is normal deformation; type II is characterized by delayed onset of shortening, reduced systolic peak strain and minor post-systolic shortening; type III is characterized by little or no systolic peak strain, predominantly systolic stretching and major post-systolic shortening. Panel B: For RV mechanical dispersion, a 6-segment model of the RV was used, including both the lateral wall and the interventricular septum. It was calculated as the standard deviation (SD) of the segmental time intervals from onset Q/R on the surface ECG to peak negative strain and expressed in milliseconds.8,9 Horizontal arrows indicate the time interval until peak shortening for each segment. Cardiac magnetic resonance imaging Cardiac magnetic resonance (CMR) imaging was performed on a 1.5-T scanner, as published previously and according to standard AC protocols.6,12 Available data were analysed for structural abnormalities fulfilling 2010 TFC.5 Conventional CMR measurements included RV enddiastolic volume indexed for BSA (RVEDVi) and RV ejection fraction (RVEF). Contrast-enhanced images with administration of gadolinium were acquired for detection of myocardial fibrosis in both ventricles, presenting as late gadolinium enhancement. 3
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