Echocardiography in acute rheumatic fever

E-mail: ramakgmc@rediffmail.com nearly 40-50% of th e patients with acute carditis and are shown to disappear following treatment of carditis.[9,10] Nodules may be more useful for diagnosing recurrence of RF among patients with established RHD, but the sensitivity and specificity of these nodules is not known. The utility of any other structural abnormality for the echocardiographic diagnosis of acute rheumatic carditis in the absence of pathological valvular regurgitation is not well established. A recent study had used a composite score of 8 echocardiographic parameters and concluded that a score of 6 out of 16 identifies echocardiographic carditis precisely.[11] However, the majority of the patients with carditis in that study had pathological mitral or aortic regurgitation.


INTRODUCTION
"It has become appallingly obvious that our technology has exceeded our humanity" -Albert Einstein.
Rheumatic heart disease (RHD) continues to remain a major health concern across the globe.[3] RHD results in enormous disease burden translating into huge economic and social losses in India.Classical rheumatic fever (RF) is still encountered across the country.The diagnosis of RF remains clinical.Valvulitis is sine qua non of acute carditis in RF and no investigation is better than echocardiography in its assessment.Echocardiography along with Doppler assessment gives excellent details of the structural and functional abnormalities in acute RF.Yet, echocardiography is not included as a criterion in the diagnosis of RF.No other indication for echocardiography has undergone such a rigorous scrutiny.In this review, a critical appraisal of the role of echocardiography in the diagnosis of RF is presented.

ECHOCARDIOGRAPHIC FEATURES OF RHEUMATIC CARDITIS
The echocardiographic features of acute rheumatic carditis are summarized in Table 1.Assessment of valvular regurgitation has to be accurate as there is a continuum between physiological and pathological regurgitation. [3,4]he characteristics of a physiological regurgitation include localized jet at the region immediately below or above the plane of valve leaflets (or within 1.0 cm), short signals and a smaller maximum regurgitant area. [3,4]The reported prevalence of physiological valvular regurgitation in normal people is mitral regurgitation in 2.4-45%, [5,6] aortic regurgitation in 0-33%, [5,6] tricuspid regurgitation in 6.3-95% [6,7] and pulmonary regurgitation in 21.9-92%. [6,8]ence, definite criteria for pathological regurgitation have been proposed [Table 1] and are widely used. [3]Rheumatic nodules (beaded appearance of leaflets) are found in nearly 40-50% of th e patients with acute carditis and are shown to disappear following treatment of carditis. [9,10]hocardiography in acute rheumatic fever

S Ramakrishnan
Department of Cardiology, All India Institute of Medical Sciences, New Delhi, India

Table 1: Echocardiographic features of rheumatic carditis
Valvular regurgitation (WHO suggested) [3] A regurgitant jet >1 cm in length A regurgitant jet in at least two planes A mosaic color jet with a peak velocity >2.Ramakrishnan: Echo in acute rheumatic fever various studies on subclinical carditis reported a weighted pooled prevalence of 16.8% (95% confidence interval [CI] 11.9-21.6).With the application of the World Health Organization echocardiographic criteria, the prevalence of subclinical carditis increased slightly to 18.1% (95% CI 11.1-25.2). [12] These estimates are based on nearly 20 studies that included more than 1700 RF cases from areas of the globe with high prevalence of RHD, except sub-Saharan Africa.
The outcome of patients with subclinical carditis is less well established.The metaanalysis reported a weighted pooled prevalence of persistence or deterioration of subclinical carditis at 3-23 months after diagnosis in 44.7% (95% CI 19.3-70.2). [12] These studies confirm that subclinical carditis persists in similar proportions to that of mild clinical carditis.However, the follow-up was not uniform and included only 99 patients among 11 studies.More importantly, the degree of worsening, details of secondary prophylaxis and proportion of patients in whom murmurs appeared on follow-up are not known.

INCLUSION OF ECHOCARDIOGRAPHY AS A "JONES CRITERION" -THE CONS
For echocardiography to be included as a diagnostic criterion, three things need to be established.Firstly, the incidence of subclinical carditis should be significant.Secondly, the outcome of subclinical carditis should not be benign and thirdly, treatment or prophylaxis should alter the outcome.Even though subclinical carditis is shown to be relatively frequent, the outcome is not well established.It is not known whether subclinical carditis follows the same evolution as audible valvular lesions.Studies of long-term follow-up have most likely included most of the patients with subclinical carditis in the no-carditis group, which is shown to have uniformly good prognosis.Additional diagnosis of carditis by echocardiography does not alter the acute treatment as only symptomatic treatment is needed in patients with mild valvular lesions.However, such patients may need additional secondary prophylaxis because the duration of prophylaxis is determined by the presence or absence of carditis. [29]Hence, it may be argued that it is wiser to perform an echocardiography before stopping prophylaxis in countries with limited resources.
Fever alone may produce pathological regurgitation that disappears with the offset of fever.Such patients may be wrongly labeled as RF.Overdiagnosis leads to undesirable stigma and exposure of patients to the rigors of an unnecessary prophylaxis.The availability of echocardiography is also limited in areas where RF is highly prevalent.The theme of arguments against the inclusion of echocardiography as a criterion is that it may pose another barrier in the diagnosis of RF.For all these reasons, it is still argued that echocardiography should not be included as a criterion for the diagnosis of RF. [30]

The suggested relative utility of echocardiography in
The major confusion for the clinician in ordering an echocardiography is in patients with polyarthritis and chorea with no clinical evidence of carditis.Patients with chorea are shown to have a high incidence of clinical/ subclinical carditis and the utility is not questioned. [15,21,34]e putative new syndromes of pediatric autoimmune neuropsychiatric disorder associated with streptococcal infection and post-streptococcal reactive arthritis should be diagnosed with extreme caution in Indian patients as many patients on follow-up may develop valvular lesions.
The utility of screening all asymptomatic school children with echocardiography is not known.Recent studies have reported an unexpectedly high prevalence of RHD in Africa with the routine use of echocardiography (21.5-30.4/1000school children). [35,36]A recent echocardiographic screening survey from India has also suggested a very high prevalence rate. [37]The authors have attributed this to subclinical carditis.The term subclinical carditis should be reserved for patients with echo-identified cardiac lesions in the clinical setting of acute RF. "Subclinical RHD" may be a preferable term for asymptomatic school children with echo-identified cardiac lesions.Because the "echo criteria for subclinical carditis" have been studied in patients with other clinical features of acute RF, it should be strictly applied to this group only.The longterm clinical outcome and the effectiveness of prophylaxis in patients with subclinical RHD should be known before this strategy is adopted in clinical practice.

RECENT GUIDELINES
The recent Australian [38] and New Zealand [39] guidelines on RF have accepted echocardiographic subclinical carditis as a major criterion.All patients with suspected or definite RF should undergo echocardiography to identify evidence of carditis.The guidelines have also categorized severity of carditis and have recommended prophylaxis accordingly.With miniaturization of technology, echocardiography in hand-held and mobile forms may be made available in remote areas of the world.The underprivileged populations need guidelines that increase the sensitivity for acute RF to help avoid underdiagnosis.Hence, in India also we need to incorporate subclinical carditis as a major criterion as any other region with high prevalence of RF/RHD.
To conclude, the utility of echocardiography in the diagnosis of subclinical carditis is well established.However, long-term outcome of patients with subclinical carditis is less well established.It is suggested that all patients with suspected or definite RF should undergo echocardiography to identify carditis and to assess the severity of carditis.Such an approach is likely to avoid wrong diagnosis and minimize underdiagnosis.