Association of Novel Locus With Rheumatic Heart Disease in Black African Individuals: Findings From the RHDGen Study.

Importance: Rheumatic heart disease (RHD), a sequela of rheumatic fever characterized by permanent heart valve damage, is the leading cause of cardiac surgery in Africa. However, its pathophysiologic characteristics and genetics are poorly understood. Understanding genetic susceptibility may aid in prevention, control, and interventions to eliminate RHD. Objective: To identify common genetic loci associated with RHD susceptibility in Black African individuals. Design, Setting, and Participants: This multicenter case-control genome-wide association study (GWAS), the Genetics of Rheumatic Heart Disease, examined more than 7 million genotyped and imputed single-nucleotide variations. The 4809 GWAS participants and 116 independent trio families were enrolled from 8 African countries between December 31, 2012, and March 31, 2018. All GWAS participants and trio probands were screened by use of echocardiography. Data analyses took place from May 15, 2017, until March 14, 2021. Main Outcomes and Measures: Genetic associations with RHD. Results: This study included 4809 African participants (2548 RHD cases and 2261 controls; 3301 women [69%]; mean [SD] age, 36.5 [16.3] years). The GWAS identified a single RHD risk locus, 11q24.1 (rs1219406 [odds ratio, 1.65; 95% CI, 1.48-1.82; P = 4.36 × 10-8]), which reached genome-wide significance in Black African individuals. Our meta-analysis of Black (n = 3179) and admixed (n = 1055) African individuals revealed several suggestive loci. The study also replicated a previously reported association in Pacific Islander individuals (rs11846409) at the immunoglobulin heavy chain locus, in the meta-analysis of Black and admixed African individuals (odds ratio, 1.16; 95% CI, 1.06-1.27; P = 1.19 × 10-3). The HLA (rs9272622) associations reported in Aboriginal Australian individuals could not be replicated. In support of the known polygenic architecture for RHD, overtransmission of a polygenic risk score from unaffected parents to affected probands was observed (polygenic transmission disequilibrium testing mean [SE], 0.27 [0.16] SDs; P = .04996), and the chip-based heritability was estimated to be high at 0.49 (SE = 0.12; P = 3.28 × 10-5) in Black African individuals. Conclusions and Relevance: This study revealed a novel candidate susceptibility locus exclusive to Black African individuals and an important heritable component to RHD susceptibility in African individuals.

Using community-led development to build health communication about rheumatic heart disease in Aboriginal children: a developmental evaluation.

OBJECTIVE: A high prevalence of acute rheumatic fever (ARF) and rheumatic heart disease (RHD) among Aboriginal children in northern Australia is coupled with low understanding among families. This has negative impacts on children's health, limits opportunities for prevention and suggests that better health communication is needed. METHODS: During an RHD echocardiography screening project, Aboriginal teachers in a remote community school created lessons to teach children about RHD in their home languages, drawing on principles of community-led development. Access to community-level RHD data, previously unknown to teachers and families, was a catalyst for this innovative work. Careful, iterative discussions among speakers of four Aboriginal languages ensured a culturally coherent narrative and accompanying teaching resources. RESULTS: The evaluation demonstrated the importance of collective work, local Indigenous Knowledge and metaphors. As a result of the lessons, some children showed new responses and attitudes to skin infections and their RHD treatment. Language teachers used natural social networks to disseminate new information. A community interagency collaboration working to prevent RHD commenced. Conclusions and implications for public health: Action to address high rates of RHD must include effective health communication strategies that value Indigenous Knowledge, language and culture, collaborative leadership and respect for Indigenous data sovereignty.

Hyperendemic rheumatic heart disease in a remote Australian town identified by echocardiographic screening.

OBJECTIVES: Using echocardiographic screening, to estimate the prevalence of rheumatic heart disease (RHD) in a remote Northern Territory town. DESIGN: Prospective, cross-sectional echocardiographic screening study; results compared with data from the NT rheumatic heart disease register. SETTING, PARTICIPANTS: People aged 5-20 years living in Maningrida, West Arnhem Land (population, 2610, including 2366 Indigenous Australians), March 2018 and November 2018. INTERVENTION: Echocardiographic screening for RHD by an expert cardiologist or cardiac sonographer. MAIN OUTCOME MEASURES: Definite or borderline RHD, based on World Heart Federation criteria; history of acute rheumatic fever (ARF), based on Australian guidelines for diagnosing ARF. RESULTS: The screening participation rate was 72%. The median age of the 613 participants was 11 years (interquartile range, 8-14 years); 298 (49%) were girls or women, and 592 (97%) were Aboriginal Australians. Definite RHD was detected in 32 screened participants (5.2%), including 20 not previously diagnosed with RHD; in five new cases, RHD was classified as severe, and three of the participants involved required cardiac surgery. Borderline RHD was diagnosed in 17 participants (2.8%). According to NT RHD register data at the end of the study period, 88 of 849 people in Maningrida and the surrounding homelands aged 5-20 years (10%) were receiving secondary prophylaxis following diagnoses of definite RHD or definite or probable ARF. CONCLUSION: Passive case finding for ARF and RHD is inadequate in some remote Australian communities with a very high burden of RHD, placing children and young people with undetected RHD at great risk of poor health outcomes. Active case finding by regular echocardiographic screening is required in such areas.

Screening Rheumatic Heart Disease in 1530 New Caledonian Adolescents.

BACKGROUND In New Caledonia, a South Pacific archipelago whose inhabitants comprise Melanesians, Europeans/whites, Wallisians, Futunans, Polynesians, and Asians, the prevalence of rheumatic heart disease (RHD) is 0.9% to 1% at ages 9 and 10. It could be higher at the age of 16, but this remains to be verified. METHODS AND RESULTS A total of 1530 Melanesian, Métis, white, Wallisian, Futunan, Polynesian, and Asian adolescents benefited from a transthoracic echocardiogram. Definite or borderline RHD, nonrheumatic valve lesions, congenital heart defects, family and personal history of acute rheumatic fever, and socioeconomic factors were collected. The prevalence of cardiac abnormalities was 8.1%, made up of 4.1% RHD including 2.4% definite and 1.7% borderline RHD, 1.7% nonrheumatic valve lesions, and 2.3% congenital anomalies. In whites and Asians, there were no cases of RHD. RHD was higher in the Wallisian, Futunan, and Polynesian group (7.6%) when compared with Melanesians (5.3%) and Métis (2.9%). The number of nonrheumatic valve lesions was not statistically different in the different ethnicities. The prevalence of RHD was higher in adolescents with a personal history of acute rheumatic fever, in those living in overcrowded conditions, and in those whose parents were unemployed or had low-income occupations, such as the farmers or manual workers. CONCLUSIONS RHD was 4 times higher in adolescents at age 16 than at ages 9 and 10 (4.1% versus 0.9%-1%). No cases of RHD were observed in whites and Asians. The determining factors were history of acute rheumatic fever and socioeconomic factors.

The high prevalence and impact of rheumatic heart disease in pregnancy in First Nations populations in a high-income setting: a prospective cohort study.

OBJECTIVE: To describe the epidemiology of rheumatic heart disease (RHD) in pregnancy in Australia and New Zealand (A&NZ). DESIGN: Prospective population-based study. SETTING: Hospital-based maternity units throughout A&NZ. POPULATION: Pregnant women with RHD with a birth outcome of ≥20 weeks of gestation between January 2013 and December 2014. METHODS: We identified eligible women using the Australasian Maternity Outcomes Surveillance System (AMOSS). De-identified antenatal, perinatal and postnatal data were collected and analysed. MAIN OUTCOME MEASURES: Prevalence of RHD in pregnancy. Perinatal morbidity and mortality. RESULTS: There were 311 pregnancies associated with women with RHD (4.3/10 000 women giving birth, 95% CI 3.9-4.8). In Australia, 78% were Aboriginal or Torres Strait Islander (60.4/10 000, 95% CI 50.7-70.0), while in New Zealand 90% were Maori or Pasifika (27.2/10 000, 95% CI 22.0-32.3). One woman (0.3%) died and one in ten was admitted to coronary or intensive care units postpartum. There were 314 births with seven stillbirths (22.3/1000 births) and two neonatal deaths (6.5/1000 births). Sixty-six (21%) live-born babies were preterm and one in three was admitted to neonatal intensive care or special care units. CONCLUSION: Rheumatic heart disease in pregnancy persists in disadvantaged First Nations populations in A&NZ. It is associated with significant cardiac and perinatal morbidity. Preconception planning and counselling and RHD screening in at-risk pregnant women are essential for good maternal and baby outcomes. TWEETABLE ABSTRACT: Rheumatic heart disease in pregnancy persists in First Nations people in Australia and New Zealand and is associated with major cardiac and perinatal morbidity.

Community-based participatory action research on rheumatic heart disease in an Australian Aboriginal homeland: Evaluation of the 'On track watch' project.

Strategies to date have been ineffective in reducing high rates of rheumatic heart disease (RHD) in Australian Aboriginal people; a disease caused by streptococcal infections. A remote Aboriginal community initiated a collaboration to work towards elimination of RHD. Based in 'both-way learning' (reciprocal knowledge co-creation), the aim of this study was to co-design, implement and evaluate community-based participatory action research (CBPAR) to achieve this vision. Activities related to understanding and addressing RHD social determinants were delivered through an accredited course adapted to meet learner and project needs. Theory-driven evaluation linking CBPAR to empowerment was applied. Data collection comprised focus groups, interviews, observation, and co-development and use of measurement tools such as surveys. Data analysis utilised process indicators from national guidelines for Aboriginal health research, and outcome indicators derived from the Wallerstein framework. Findings include the importance of valuing traditional knowledges and ways of learning such as locally-meaningful metaphors to explore unfamiliar concepts; empowerment through critical thinking and community ownership of knowledge about RHD and research; providing practical guidance in implementing empowering and decolonising principles / theories. Lessons learned are applicable to next stages of the RHD elimination strategy which must include scale-up of community leadership in research agenda-setting and implementation.

How Many Doses Make a Difference? An Analysis of Secondary Prevention of Rheumatic Fever and Rheumatic Heart Disease.

Background Acute rheumatic fever ( ARF ) and rheumatic heart disease cause substantial burdens worldwide. Long-term antibiotic secondary prophylaxis is used to prevent disease progression, but evidence for benefits of different adherence levels is limited. Using data from northern Australia, we identified factors associated with adherence, and the association between adherence and ARF recurrence, progression to rheumatic heart disease, worsening or improvement of rheumatic heart disease, and mortality. Methods and Results Factors associated with adherence (percent of doses administered) were analyzed using logistic regression. Nested case-control and case-crossover designs were used to investigate associations with clinical outcomes; conditional logistic regression was used to estimate odds ratios ( OR ) with 95% CIs Adherence estimates (7728) were analyzed. Being female, younger, having more-severe disease, and living remotely were associated with higher adherence. Alcohol misuse was associated with lower adherence. The risk of ARF recurrence did not decrease until ≈40% of doses had been administered. Receiving <80% was associated with a 4-fold increase in the odds of ARF recurrence (case-control OR : 4.00 [95% CI : 1.7-9.29], case-crossover OR : 3.31 [95% CI : 1.09-10.07]) and appeared to be associated with increased all-cause mortality (case-control OR : 1.90 [95% CI : 0.89-4.06]; case-crossover OR 1.91 [95% CI : 0.51-7.12]). Conclusions We show for the first time that increased adherence to penicillin prophylaxis is associated with reduced ARF recurrence, and a likely reduction in mortality, in our setting. These findings can motivate patients to receive doses since even relatively low adherence can be beneficial, and additional doses further reduce adverse clinical outcomes.

Qualitative Evaluation of a Complex Intervention to Improve Rheumatic Heart Disease Secondary Prophylaxis.

BACKGROUND: Rheumatic heart disease is a high-burden condition in Australian Aboriginal communities. We evaluated a stepped-wedge, community, randomized trial at 10 Aboriginal communities from 2013 to 2015. A multifaceted intervention was implemented using quality improvement and chronic care model approaches to improve delivery of penicillin prophylaxis for rheumatic heart disease. The trial did not improve penicillin adherence. This mixed-methods evaluation, designed a priori, aimed to determine the association between methodological approaches and outcomes. METHODS AND RESULTS: An evaluation framework was developed to measure the success of project implementation and of the underlying program theory. The program theory posited that penicillin delivery would be improved through activities implemented at clinics that addressed elements of the chronic care model. Qualitative data were derived from interviews with health-center staff, informants, and clients; participant observation; and project officer reports. Quantitative data comprised numbers and types of "action items," which were developed by participating clinic staff with project officers to improve delivery of penicillin injections. Interview data from 121 health-center staff, 22 informants, and 72 clients revealed barriers to achieving the trial's aims, including project-level factors (short trial duration), implementation factors (types of activities implemented), and contextual factors (high staff turnover and the complex sociocultural environment). Insufficient actions were implemented addressing "self-management support" and "community linkage" streams of the chronic care model. Increased momentum was evident in later stages of the study. CONCLUSIONS: The program theory underpinning the study was sound. The limited impact made by the study on adherence was attributable to complex implementation challenges.

Rheumatic heart disease in pregnancy: strategies and lessons learnt implementing a population-based study in Australia.

Background: The global burden of rheumatic heart disease (RHD) is two-to-four times higher in women, with a heightened risk in pregnancy. In Australia, RHD is found predominantly among Aboriginal and Torres Strait Islander peoples. Methods: This paper reviews processes developed to identify pregnant Australian women with RHD during a 2-year population-based study using the Australasian Maternity Outcomes Surveillance System (AMOSS). It evaluates strategies developed to enhance reporting and discusses implications for patient care and public health. Results: AMOSS maternity coordinators across 262 Australian sites reported cases. An extended network across cardiac, Aboriginal and primary healthcare strengthened surveillance and awareness. The network notified 495 potential cases, of which 192 were confirmed. Seventy-eight per cent were Aboriginal and/or Torres Strait Islander women, with a prevalence of 22 per 1000 in the Northern Territory. Discussion: Effective surveillance was challenged by a lack of diagnostic certainty, incompatible health information systems and varying clinical awareness among health professionals. Optimal outcomes for pregnant women with RHD demand timely diagnosis and access to collaborative care. Conclusion: The strategies employed by this study highlight gaps in reporting processes and the opportunity pregnancy provides for diagnosis and re/engagement with health services to support better continuity of care and promote improved outcomes.

Rheumatic heart disease in pregnancy: How can health services adapt to the needs of Indigenous women? A qualitative study.

OBJECTIVES: To study rheumatic heart disease health literacy and its impact on pregnancy, and to identify how health services could more effectively meet the needs of pregnant women with rheumatic heart disease. MATERIALS AND METHODS: Researchers observed and interviewed a small number of Aboriginal women and their families during pregnancy, childbirth and postpartum as they interacted with the health system. An Aboriginal Yarning method of relationship building over time, participant observations and interviews with Aboriginal women were used in the study. The settings were urban, island and remote communities across the Northern Territory. Women were followed interstate if they were transferred during pregnancy. The participants were pregnant women and their families. We relied on participants' abilities to tell their own experiences so that researchers could interpret their understanding and perspective of rheumatic heart disease. RESULTS: Aboriginal women and their families rarely had rheumatic heart disease explained appropriately by health staff and therefore lacked understanding of the severity of their illness and its implications for childbearing. Health directives in written and spoken English with assumed biomedical knowledge were confusing and of limited use when delivered without interpreters or culturally appropriate health supports. CONCLUSIONS: Despite previous studies documenting poor communication and culturally inadequate care, health systems did not meet the needs of pregnant Aboriginal women with rheumatic heart disease. Language-appropriate health education that promotes a shared understanding should be relevant to the gender, life-stage and social context of women with rheumatic heart disease.

Association between a common immunoglobulin heavy chain allele and rheumatic heart disease risk in Oceania.

The indigenous populations of the South Pacific experience a high burden of rheumatic heart disease (RHD). Here we report a genome-wide association study (GWAS) of RHD susceptibility in 2,852 individuals recruited in eight Oceanian countries. Stratifying by ancestry, we analysed genotyped and imputed variants in Melanesians (607 cases and 1,229 controls) before follow-up of suggestive loci in three further ancestral groups: Polynesians, South Asians and Mixed or other populations (totalling 399 cases and 617 controls). We identify a novel susceptibility signal in the immunoglobulin heavy chain (IGH) locus centring on a haplotype of nonsynonymous variants in the IGHV4-61 gene segment corresponding to the IGHV4-61*02 allele. We show each copy of IGHV4-61*02 is associated with a 1.4-fold increase in the risk of RHD (odds ratio 1.43, 95% confidence intervals 1.27-1.61, P=4.1 × 10-9). These findings provide new insight into the role of germline variation in the IGH locus in disease susceptibility.

Newly diagnosed rheumatic heart disease among indigenous populations in the Pacific.

OBJECTIVES: Rheumatic heart disease (RHD) remains the leading acquired heart disease in the young worldwide. We aimed at assessing outcomes and influencing factors in the contemporary era. METHODS: Hospital-based cohort in a high-income island nation where RHD remains endemic and the population is captive. All patients admitted with newly diagnosed RHD according to World Heart Federation echocardiographic criteria were enrolled (2005-2013). The incidence of major cardiovascular events (MACEs) including heart failure, peripheral embolism, stroke, heart valve intervention and cardiovascular death was calculated, and their determinants identified. RESULTS: Of the 396 patients, 43.9% were male with median age 18 years (IQR 10-40)). 127 (32.1%) patients presented with mild, 131 (33.1%) with moderate and 138 (34.8%) with severe heart valve disease. 205 (51.8%) had features of acute rheumatic fever. 106 (26.8%) presented with at least one MACE. Among the remaining 290 patients, after a median follow-up period of 4.08 (95% CI 1.84 to 6.84) years, 7 patients (2.4%) died and 62 (21.4%) had a first MACE. The annual incidence of first MACE and of heart failure were 59.05‰ (95% CI 44.35 to 73.75) and 29.06‰ (95% CI 19.29 to 38.82), respectively. The severity of RHD at diagnosis (moderate vs mild HR 3.39 (0.95 to 12.12); severe vs mild RHD HR 10.81 (3.11 to 37.62), p<0.001) and ongoing secondary prophylaxis at follow-up (HR 0.27 (0.12 to 0.63), p=0.01) were the two most influential factors associated with MACE. CONCLUSIONS: Newly diagnosed RHD is associated with poor outcomes, mainly in patients with moderate or severe valve disease and no secondary prophylaxis.

A review of outcome following valve surgery for rheumatic heart disease in Australia.

BACKGROUND: Globally, rheumatic heart disease (RHD) remains an important cause of heart disease. In Australia it particularly affects younger Indigenous and older non-Indigenous Australians. Despite its impact there is limited understanding of the factors influencing outcome following surgery for RHD. METHODS: The Australian and New Zealand Society of Cardiac and Thoracic Surgeons Cardiac Surgery Database was analysed to assess outcomes following surgical procedures for RHD and non-RHD valvular disease. The association with demographics, co-morbidities, pre-operative status, valve(s) affected and operative procedure was evaluated. RESULTS: Outcome of 1384 RHD and 15843 non-RHD valve procedures was analysed. RHD patients had longer ventilation, experienced fewer strokes and had more readmissions to hospital and anticoagulant complications. Mortality following RHD surgery at 30 days was 3.1% (95% CI 2.2 - 4.3), 5 years 15.3% (11.7 - 19.5) and 10 years 25.0% (10.7 - 44.9). Mortality following non-RHD surgery at 30 days was 4.3% (95% CI 3.9 - 4.6), 5 years 17.6% (16.4 - 18.9) and 10 years 39.4% (33.0 - 46.1). Factors independently associated with poorer longer term survival following RHD surgery included older age (OR1.03/additional year, 95% CI 1.01 - 1.05), concomitant diabetes (OR 1.7, 95% CI 1.1 - 2.5) and chronic kidney disease (1.9, 1.2 - 2.9), longer invasive ventilation time (OR 1.7 if greater than median value, 1.1- 2.9) and prolonged stay in hospital (1.02/additional day, 1.01 - 1.03). Survival in Indigenous Australians was comparable to that seen in non-Indigenous Australians. CONCLUSION: In a large prospective cohort study we have demonstrated survival following RHD valve surgery in Australia is comparable to earlier studies. Patients with diabetes and chronic kidney disease, were at particular risk of poorer long-term survival. Unlike earlier studies we did not find pre-existing atrial fibrillation, being an Indigenous Australian or the nature of the underlying valve lesion were independent predictors of survival.

Are minor echocardiographic changes associated with an increased risk of acute rheumatic fever or progression to rheumatic heart disease?

BACKGROUND: The World Heart Federation criteria for the echocardiographic diagnosis of rheumatic heart disease (RHD) include a category "Borderline" RHD which may represent the earliest evidence of RHD. We aimed to determine the significance of minor heart valve abnormalities, including Borderline RHD, in predicting the future risk of acute rheumatic fever (ARF) or RHD. METHODS: A prospective cohort study of Aboriginal and Torres Strait Islander children aged 8 to 18 years was conducted. Cases comprised children with Borderline RHD or other minor non-specific valvular abnormalities (NSVAs) detected on prior echocardiography. Controls were children with a prior normal echocardiogram. Participants underwent a follow-up echocardiogram 2.5 to 5 years later to assess for progression of valvular changes and development of Definite RHD. Interval diagnoses of ARF were ascertained. RESULTS: There were 442 participants. Cases with Borderline RHD were at significantly greater risk of ARF (incidence rate ratio 8.8, 95% CI 1.4-53.8) and any echocardiographic progression of valve lesions (relative risk 8.19, 95% CI 2.43-27.53) than their Matched Controls. Cases with Borderline RHD were at increased risk of progression to Definite RHD (1 in 6 progressed) as were Cases with NSVAs (1 in 10 progressed). CONCLUSIONS: Children with Borderline RHD had an increased risk of ARF, progression of valvular lesions, and development of Definite RHD. These findings provide support for considering secondary antibiotic prophylaxis or ongoing surveillance echocardiography in high-risk children with Borderline RHD.

Acute rheumatic fever and rheumatic heart disease in the Kimberley: using hospitalisation data to find cases and describe trends.

OBJECTIVE: To describe the epidemiology of hospitalisations due to acute rheumatic fever (ARF) and rheumatic heart disease (RHD) in the Kimberley region of Western Australia (WA) and use these data to improve completeness of the WA RHD Register. METHODS: Retrospective analysis of Kimberley regional hospitalisation data for hospitalisations coded as ARF/RHD from 01/07/2002 to 30/06/2012, with individual follow-up of those not on the register. Annual age-standardised hospitalisation rates were calculated to determine hospitalisation trend. RESULTS: There were 250 admissions among 193 individuals. Of these, 53 individuals (27%) with confirmed or probable ARF/RHD were not on the register. Males were less likely to be on the register (62% versus 79% of females, p<0.01), as were those hospitalised with ARF without heart involvement (68% versus 87% of other ARF diagnoses, p<0.01). ARF/RHD hospitalisation rates decreased by 8.8% per year (p<0.001, rate ratio = 0.91, 95%CI 0.87-0.96). CONCLUSIONS AND IMPLICATIONS: Using hospitalisation data is an effective method of identifying cases of ARF/RHD not currently on the register. This process could be undertaken for initial case finding in areas with newly established registers, or as regular quality assurance in areas with established register-based programs. Reasons for the observed decrease in hospitalisation rates remain unclear and warrant further investigation.

Acute rheumatic fever in First Nations communities in northwestern Ontario: Social determinants of health "bite the heart".

OBJECTIVE: To document a case series of 8 young First Nations patients diagnosed with acute rheumatic fever (ARF), a preventable disease that resulted in the death of 2 patients, in northwestern Ontario in the context of late diagnosis, overcrowded housing, and inadequate public health response. DESIGN: Retrospective case series over an 18-month period. SETTING: Remote First Nations communities in northwestern Ontario. PARTICIPANTS: Eight patients with ARF. MAIN OUTCOME MEASURES: Incidence, mortality, residual rheumatic heart disease, time to diagnosis, barriers to diagnosis and treatment, housing situation of patients, patient demographic characteristics (age, sex), and investigation results. RESULTS: The incidence of ARF in this population was 21.3 per 100,000, which is 75 times greater than the overall Canadian estimated incidence. The average patient age was 9.4 years. Most cases developed joint findings, and 5 of the surviving patients had rheumatic heart disease when they received echocardiography. The average time to diagnosis was 88 days. Two 4-year-old children died from ARF. Most patients lived in inadequate and crowded housing. CONCLUSION: This rare disease still exists in remote First Nations communities. These communities demonstrate an incidence equal to that in aboriginal communities in Australia and New Zealand, which have among the highest international incidence of ARF. Primordial prevention, including improved on-reserve housing, is urgently needed. Case detection and ongoing surveillance for primary and secondary prophylaxis requires a well resourced regional strategy.

Prevalence of rheumatic heart disease in young adults from New Caledonia.

BACKGROUND: Rheumatic heart disease (RHD) is an important public health issue, particularly in the Pacific region, but its true burden is unknown. OBJECTIVES: To evaluate the prevalence of rheumatic heart disease (RHD) in young adults from New Caledonia, based on echocardiography, and to evaluate the accuracy of dynamic criteria, focusing on mitral valve (MV) leaflet motion. METHODS: Blind analysis of echocardiography by three cardiologists; diagnosis of RHD required at least one dynamic criterion (exaggerated or restricted MV leaflet motion); subjects with morphological criteria (MV leaflet thickening), but without dynamic criteria, were considered as borderline. RESULTS: There were 834 subjects from three socioeconomic groups, aged 18-22 years: 699 had normal echocardiography; 93 (11.5%) had physiological regurgitation; nine (0.9%) had borderline RHD; and five (0.59%) had RHD. The prevalence of RHD in New Caledonia was thus estimated at 5.9 per 1000 (95% confidence interval 2.6-12.2). The RHD cases were of Pacific ethnicity. Physiological regurgitation was more frequent in Pacific subjects (13.7%) than in non-Pacific subjects (6.9%; P<0.0001). RHD was more prevalent in the lowest socioeconomic group. No disagreement occurred between the three reviewers concerning analysis of dynamic criteria; all disagreements were related to morphological criteria. CONCLUSIONS: The prevalence of echocardiographically diagnosed RHD in adults in New Caledonia is estimated at 5.9 per 1000; it occurs most frequently in Pacific subjects and those with low incomes. Dynamic criteria were more accurate and reproducible than standard morphological criteria.