Cardiac strain findings in children with latent rheumatic heart disease detected by echocardiographic screening.

BACKGROUND: Identification of patients with latent rheumatic heart disease by echocardiography presents a unique opportunity to prevent disease progression. Myocardial strain is a more sensitive indicator of cardiac performance than traditional measures of systolic function. OBJECTIVE: The objective of this study was to test the hypothesis that abnormalities in myocardial strain may be present in children with latent rheumatic heart disease. METHODS: Standard echocardiography images with electrocardiogram gating were obtained from Ugandan children found to have latent rheumatic heart disease as well as control subjects. Traditional echocardiography measures of systolic function were obtained, and offline global longitudinal strain analysis was performed. Comparison between groups was performed using strain as a continuous (Mann-Whitney U-test) and categorical (cut-off 5th percentile for age) variable. RESULTS: Our study included 14 subjects with definite rheumatic heart disease, 13 with borderline rheumatic heart disease, and 112 control subjects. None of the subjects had abnormal left ventricular size or ejection fraction. Global longitudinal strain was lower than the 5th percentile in 44% of the subjects with any rheumatic heart disease (p=0.002 versus controls) and 57% of the subjects with definite rheumatic heart disease (p=0.03). The mean absolute strain values were significantly lower when comparing subjects with any rheumatic heart disease with controls (20.4±3.95 versus 22.4±4.35, p=0.025) and subjects with definite rheumatic heart disease with controls (19.9±4.25 versus 22.4±4.35, p=0.033). CONCLUSION: Global longitudinal strain is decreased in subjects with rheumatic heart disease in the absence of abnormal systolic function. Larger studies with longer-term follow-up are required to determine whether there is a role for strain to help better understand the pathophysiology of latent rheumatic heart disease.

Efficacy of a Standardized Computer-Based Training Curriculum to Teach Echocardiographic Identification of Rheumatic Heart Disease to Nonexpert Users.

The ability to integrate echocardiographic for rheumatic heart disease (RHD) into RHD prevention programs is limited because of lack of financial and expert human resources in endemic areas. Task shifting to nonexperts is promising; but investigations into workforce composition and training schemes are needed. The objective of this study was to test nonexperts' ability to interpret RHD screening echocardiograms after a brief, standardized, computer-based training course. Six nonexperts completed a 3-week curriculum on image interpretation. Participant performance was tested in a school-screening environment in comparison to the reference approach (cardiologists, standard portable echocardiography machines, and 2012 World Heart Federation criteria). All participants successfully completed the curriculum, and feedback was universally positive. Screening was performed in 1,381 children (5 to 18 years, 60% female), with 397 (47 borderline RHD, 6 definite RHD, 336 normal, and 8 other) referred for handheld echo. Overall sensitivity of the simplified approach was 83% (95% CI 76% to 89%), with an overall specificity of 85% (95% CI 82% to 87%). The most common reasons for false-negative screens (n = 16) were missed mitral regurgitation (MR; 44%) and MR ≤1.5 cm (29%). The most common reasons for false-positive screens (n = 179) included identification of erroneous color jets (25%), incorrect MR measurement (24%), and appropriate application of simplified guidelines (39.4%). In conclusion, a short, independent computer-based curriculum can be successfully used to train a heterogeneous group of nonexperts to interpret RHD screening echocardiograms. This approach helps address prohibitive financial and workforce barriers to widespread RHD screening.