Lowitja Institute scholarship holder Dr Bo Remenyi is the lead author for the world’s first evidence-based diagnostic guidelines on the use of echocardiograms to check for rheumatic heart disease (RHD), with the work forming part of her current PhD research.
Echocardiograms are ultrasound images of the heart’s valves and chambers. Over the past decade they have become a key tool around the world to provide more accurate diagnoses of RHD, especially in cases where there is little or no clinical record of previous episodes of rheumatic fever (which leads onto RHD). Until now, however, different echocardiographic criteria have been used in different countries to establish a diagnosis of RHD.
The new guidelines were developed by an international research team supported by the World Heart Foundation, and are aimed at standardising the minimal requirements for a consistent and reproducible diagnosis of RHD around the world. The guidelines were first published earlier this year in Nature Reviews Cardiology.
RHD, which can result in irreversible damage to the heart valves, is a disease of poverty that has been virtually eliminated from the developed world but still afflicts Australia’s First Peoples at rates comparable to people living in the poorest countries. Approximately 1 per cent of all school-aged Aboriginal and Torres Strait Islander children in the Northern Territory, rising to 2 per cent of young adults, suffer the disease and its long-term complications: these include heart failure, strokes, arrhythmias, infective endocarditis and, of course, an increased risk of premature death.
Dr Remenyi says the guidelines should ‘not only lead to improved long-term patient outcomes but will increase the vitality of data available for epidemiological studies as well as the ability to monitor and evaluate the success of RHD interventions’.
Although echocardiography has revealed the burden of RHD is greater than previously thought, there are also concerns it could be overly sensitive to normal variations that occur within the hearts of healthy children. As a result, the new guidelines clearly state what are considered to be normal echocardiographic findings in children to avoid over-diagnosis. In addition, they ensure that other factors – such as the person’s geographical location, ethnicity and living environment – are considered before a definitive diagnosis of RHD is made.
‘A common scenario is a child with an incidental finding of a cardiac murmur,’ Dr Remenyi says. ‘The majority of the childhood cardiac murmurs are innocent; that is, there is no structural or functional abnormality of the heart. Innocent murmurs occur in up to a third of healthy school-aged children.
‘But in settings where RHD is endemic, the stakes are high. Innocent murmurs must be differentiated from mild RHD as early detection of RHD and commencement of long-term preventive treatment in the form of four-weekly penicillin injections can be life saving – it prevents rheumatic fever recurrences and hence worsening of heart disease.’
She says the potential role of population-based echocardiographic screening for RHD in Aboriginal and Torres Strait Islander Australians is currently being evaluated.
Dr Bo Remenyi is a PhD scholar at the Menzies School of Health Research and a paediatric cardiologist at the Royal Darwin Hospital and Northern Territory Cardiac Services. The guidelines appear in the 28 February 2012 advance online edition of Nature Reviews Cardiology, download the abstract.
More information on project: Standardisation of diagnostic protocols for early detection of rheumatic heart disease