Echocardiography has been the pivotal investigation used by cardiologists assessing cardiac valvar disease for the last three decades. It is diagnostic and often prognostic whatever the aetiology of the cardiac valvar disease. Echocardiography is more accurate than clinical evaluation by experienced cardiologists.Reference Jaffe, Roche, Coverdale, McAlister, Ormiston and Greene¹ In rheumatic cardiac disease echocardiography is the key investigation for serial assessment of valvar and ventricular function.

The entity of subclinical valvar regurgitation, defined as pathological mitral or aortic regurgitation inaudible to skilled auscultation, is not a clinical concern in most cardiac disease as these lesions are not of haemodynamic importance. However in acute rheumatic fever, subclinical carditis is of considerable diagnostic importance, as it may be the only manifestation of carditis in acute rheumatic fever.

There is convincing evidence that subclinical or silent echocardiographic carditis is part of the spectrum of rheumatic carditis and should not be ignored. It has been found by all investigators in regions of the world with endemic rheumatic fever, including EuropeReference Karaaslan, Demiroren, Oran, Baysal, Baspinar and Ucar^2, Reference Cotrim, Macedo, Duarte and Lima³ the Middle East,Reference Folger, Hajar, Robida and Hajar⁴ Asia,Reference Agarwal, Misra, Sarkari, Gupta and Agarwal^5–Reference Regmi and Pandey⁷ Oceania,Reference Abernethy, Bass and Sharpe^8–Reference Maheu, Costes and Lionet¹² North America,Reference Veasy, Wiedmeier and Orsmond^13–Reference Minich, Tani, Pagotto, Shaddy and Veasy¹⁵ and South America.Reference Mota^16–Reference Hilario, Andrade, Gasparian, Carvalho, Andrade and Len²⁰ Three of the above publications specifically address follow-up of subclinical carditis,Reference Lanna, Tonelli, Barros, Goulart and Mota^17, Reference Figueroa, Fernandez and Valdes^19, Reference Hilario, Andrade, Gasparian, Carvalho, Andrade and Len²⁰ confirming that it persists in similar proportions to that of mild clinical carditis.Reference Voss, Wilson and Neutze^10, Reference Veasy, Tani and Hill^14, Reference Wilson, Voss, Neutze, Ameratunga and Lennon²¹ Not surprisingly many of these authors advocate that subclinical carditis is incorporated into the Jones criteria as evidence of carditis. This is relevant globally as 80% of the world’s children still live in regions with high prevalence of rheumatic fever and rheumatic cardiac disease.Reference Carapetis²²

Duckett Jones proposed the guidelines for acute rheumatic fever in 1944,Reference Jones²³ at which time echocardiography did not exist. Successive revisions and updates of the Jones criteria by the American Heart Association have occurred, each change aiming to increase the specificity of the criteria but decrease sensitivity. Before the last major review of the guidelines in 1992,²⁴ there were few reports of subclinical carditis but there were many by 2002,Reference Ferrieri²⁵ when once again subclinical carditis was not endorsed as a major criterion for acute rheumatic fever. The American Heart Association committee may not have appreciated that it is not just the lower end of mild valvar regurgitation that is subclinical, but in the acute phase even moderate mitral or aortic regurgitation may be inaudible with a stethoscope. The committee was also comprised mainly of non-cardiologists.

Today echocardiography is used to its fullest extent by cardiologists to assess not only subclinical carditis but clinical carditis by defining myocarditis, pericarditis and the severity of valvulitis. Echocardiography is used to visualize the anatomy of the mitral and aortic valves, defining rheumatic structural changes as well as the severity of valvar regurgitation, especially helpful in the presence of mixed valvar disease including tricuspid valvulitis. Echocardiography will confirm the presence of a pericardial effusion in suspected pericarditis, and may reveal valvar regurgitation that is inaudible due to the pericardial fiction rub. It defines ventricular function as a measure of myocardial involvement in carditis. Portable echocardiograms and mobile echocardiographers should enable use of echocardiography to be introduced into more regions of the world, even in countries with very low income.

The minimal criteria for a diagnosis of abnormal mitral or aortic valvar regurgitation are summarised in Table 1. To be classified as pathological, both the colour and Doppler signals must be holodiastolic for aortic regurgitation, or holosystolic for mitral regurgitation. The Doppler signal must be a high velocity signal with a well-defined spectral envelope, using pulsed or continuous wave. Those experienced in echocardiography in areas with endemic rheumatic fever agree that these features can usually readily separate the normal child with a small colour jet of physiological regurgitation from the child with pathological regurgitation.Reference Karaaslan, Demiroren, Oran, Baysal, Baspinar and Ucar^2–Reference Folger, Hajar, Robida and Hajar^4, Reference Abernethy, Bass and Sharpe^8, Reference Wilson and Neutze^9, Reference Veasy, Tani and Hill^14–Reference Hilario, Andrade, Gasparian, Carvalho, Andrade and Len²⁰

Table 1

Echocardiographic criterions for subclinical carditis.

*From the NZ RF guidelines Table 6²⁸ Reproduced with permission.

**The WHO suggested a minimal jet length of 1 cm from the mitral valve leaflets³² but experience shows that many central 1 cm colour jets will not have a well defined high velocity spectral envelope. Most 2 cm long colour jets usually do meet these Doppler requirements and this jet length is more likely to avoid over diagnosis. However, posterior jets of less than 2 cm hitting the back wall of the left atrium may then dissipate out of the echocardiographic plane yet clearly be “substantial” and pathological, hence the importance of assessment in more than one echocardiographic plane.

There are now guidelines incorporating subclinical carditis as a major manifestation for acute rheumatic fever in New ZealandReference Atatoa-Carr, Lennon and Wilson²⁶ and Australia.Reference Carapetis, Brown, Wilson and Edwards²⁷ The full guidelines can be found on the world wide web through these countries’ national Heart Foundations.^{28, 29}

The guidelines are evidence-based, and were developed by consensus expert opinion with wide endorsement by Australian and New Zealand health organisations. As there is no laboratory test for the diagnosis of acute rheumatic fever, it is not possible to prove scientifically that a new set of clinical criterions are more accurate than a previous set. The current article by Vijayalakshmi and colleaguesReference Vijayalakshmi, Vishnuprabhu, Chitra, Rajasri and Anuradha³⁰ has confirmed that the current Jones criterions lack sensitivity for the presence of carditis in acute rheumatic fever. Fifty-two of 333 (16%) more patients were diagnosed as having definite acute rheumatic fever than would have been using the American Heart Association Jones criterions. This is similar to a recent experience in New Zealand, where subclinical carditis influenced the diagnosis to definite acute rheumatic fever in 11% more cases than using the American Heart Association criterions even though it was present in 31% of cases.Reference Wilson, Morreau, Voss, Stewart and Lennon³¹ Vijayalakshmi and colleaguesReference Vijayalakshmi, Vishnuprabhu, Chitra, Rajasri and Anuradha³⁰ also add a requirement that valvar morphological features should also be present to diagnose subclinical carditis. This will help increase specificity and will help avoid over-diagnosis. Morphologic changes, however, are not always present early in acute rheumatic fever, so most authors have not recommended them as a requirement for the diagnosis of subclinical carditis.

Consider where a clinician makes the diagnosis of acute rheumatic fever based on the auscultatory findings of a systolic murmur misjudged to be mitral regurgitation, but subsequently found to have no mitral regurgitation by echocardiography. Clinicians have had no hesitation in correcting their false positive diagnosis of carditis. It would be unethical to subject a child to years of prophylaxis with penicillin based on incorrect auscultatory findings. Yet this situation has undoubtedly occurred since the inception of the Jones criterions³² and still occurs where echocardiography is not available. Clinicians are not as accurate as echocardiography.Reference Jaffe, Roche, Coverdale, McAlister, Ormiston and Greene^1, Reference Wilson and Neutze³³ The likelihood of false positive misclassification is even higher now if echocardiography is not utilized, as young physicians are less proficient at auscultation than in earlier years.Reference Mahnke, Nowalk, Hofkosh, Zuberbuhler and Law³⁴ Cardiologists have frequently observed that flow murmurs are mistakenly diagnosed as mitral regurgitation by hospital clinicians assessing children considered to have acute rheumatic fever.

Consider the converse, that of false negative diagnosis. When a child has subclinical carditis its use will avoid under-diagnosis of acute rheumatic fever if the child has no other major criterion of acute rheumatic fever. Experienced clinicians in countries with endemic rheumatic fever are not radically changing the Jones criterions, rather, they are applying a more sensitive and more accurate tool for the diagnosis of carditis. As noted above, using subclinical carditis as a major Jones manifestation influences the diagnosis of definite acute rheumatic fever in an extra 11–16% only. In the majority of patients the major criterion of acute rheumatic fever is either polyarthritis, clinically overt carditis or chorea. Subclinical carditis does play a role of helping to reinforce to families the diagnosis of acute rheumatic fever and need for secondary prophylaxis with penicillin.