Task-sharing echocardiographic screening for rheumatic heart disease with community health workers in First Nations Australian communities: implementation outcomes and realist evaluation from the NEARER SCAN study

Background: Rheumatic heart disease (RHD) remains a major cause of premature death in low- and middle-income countries and First Nations communities. Early detection and management can prevent progression, but requires echocardiography, which is limited in high-burden settings. Task-sharing echocardiographic screening is an accessible, evidence-based approach but implementation remains unclear. Methods: We conducted a prospective implementation evaluation of a co-designed task-sharing screening programme across five remote First Nations Australian communities between May 2023 and November 2025. Predominantly community health workers (CHWs), alongside nurses and doctors, were trained to scan using handheld devices with off-site cardiologist interpretation. We assessed implementation outcomes and used a realist evaluation to explore how context shaped CHWs ability to complete training and embed screening into routine work. Data included scanning activity, surveys, costing, interviews, focus groups, and field notes. Findings: We trained 32 staff (21 CHWs, 8 nurses, 3 doctors) to scan across five sites. Scanning frequency was lower and more variable than anticipated: 360 scans (including training and post-certification) of 5 - 20 year olds over 14 months, with site-level coverage of 3 - 85%. Fidelity was limited by device unavailability, charging problems, and delays in uploads and reviews. Set-up and training cost A$51,903 per site, plus A$9,858/year in implementation support. Screening was easier for CHWs to embed when the legitimacy of their role as a scanner was communicated, but harder when invisible work outweighed opportunities to scan. Interpretation: Future implementation will require efforts to legitimise CHWs scanning and support invisible work. Event-based screening offers a promising complementary strategy. Scale-up requires policy support. Funding: This research was funded by the Australian Medical Research Futures Fund Cardiovascular Health Mission (GNT2015869), in addition to philanthropic donations from Medtronic Australasia, Edwards Life Sciences and the Rotary Club of Kiama. Hand-held devices (Philips Lumify, USA) were donated by Humpty Dumpty Foundation and East Timor Hearts Fund.