Introduction: Different echocardiographic definitions of Rheumatic Heart Disease (RHD) have been used for screening for RHD. This led to development of the 2012 evidence-based World Heart Federation (WHF) echocardiographic criteria for RHD. Objectives: To determine if the WHF criteria allow for consistent and reproducible differentiation of normal echocardiographic findings from mild RHD. Methods: Participants were 16 international cardiologists. A standard set of 200 echocardiograms was collated from population-based surveys of school-aged children in regions of high RHD prevalence in Australia and New Zealand. Echocardiograms were uploaded for blinded web-based reporting. Inter-observer variability in categorizing echocardiograms as normal, borderline or definite RHD, as per WHF criteria, was measured by comparing individual readings with a reference reading (majority reading if greater than 2/3 consensus, external panel consensus reading otherwise). Agreement in diagnosis of pathologic mitral and aortic regurgitation and morphologic features of RHD were assessed. One hundred echocardiograms were re-reported blindly for intra-observer assessment. Results: 3112 reports were analysed. Based on the reference readings, distribution of cases were: 67 (33.5%) borderline RHD, 53 (26.5%) definite RHD and 80 (40%) no RHD. Overall agreement in categorising echocardiograms as normal, borderline and definite RHD (primary end-point) was good, kappa 0.68 (95%CI 0.66-0.70; SE 0.0152, p-value <0.0001). Fig 1 shows inter/intra-observer agreement, sensitivity and specificity of individual readers. Agreement for pathologic mitral regurgitation was excellent, kappa 0.87 (95%CI 0.85-0.89), Fig 2. Agreement for subtle morphologic changes of RHD was variable ranging from fair to good.
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