An acute rheumatic fever immune signature comprising inflammatory markers, IgG3, and Streptococcus pyogenes-specific antibodies.

Understanding the immune profile of acute rheumatic fever (ARF), a serious post-infectious sequelae of Streptococcal pyogenes (group A Streptococcus [GAS]), could inform disease pathogenesis and management. Circulating cytokines, immunoglobulins, and complement were analyzed in participants with first-episode ARF, swab-positive GAS pharyngitis and matched healthy controls. A striking elevation of total IgG3 was observed in ARF (90% > clinical reference range for normal). ARF was also associated with an inflammatory triad with significant correlations between interleukin-6, C-reactive protein, and complement C4 absent in controls. Quantification of GAS-specific antibody responses revealed that subclass polarization was remarkably consistent across the disease spectrum; conserved protein antigens polarized to IgG1, while M-protein responses polarized to IgG3 in all groups. However, the magnitude of responses was significantly higher in ARF. Taken together, these findings emphasize the association of exaggerated GAS antibody responses, IgG3, and inflammatory cytokines in ARF and suggest IgG3 testing could beneficially augment clinical diagnosis.

High burden of rheumatic heart disease confirmed by echocardiography among Pacific adults living in New Zealand.

BACKGROUND: Despite numerous echocardiographic screening studies of children in high incidence acute rheumatic fever (ARF)/rheumatic heart disease (RHD) communities, little is known about the prevalence of RHD in adults in these populations.We sought to determine the prevalence of RHD in an urban area of South Auckland, New Zealand, where previous studies had shown the prevalence of RHD in children to be around 2%. METHODS: A cross-sectional screening study was conducted between 2014 and 2016. Echocardiography clinics were conducted at an urban Pacific-led primary healthcare clinic in New Zealand. Eligible persons aged 16-40 years were recruited according to a stratified randomised approach. Echocardiograms were performed with a standardised image acquisition protocol and reported by cardiologists. RESULTS: There were 465 individuals who underwent echocardiograms. The overall prevalence of RHD (define and borderline) was 56 per 1000 (95% CI 36 to 78 per 1000). Definite RHD was found in 10 individuals (4 of whom were already under cardiology review at a hospital clinic) with a prevalence of 22 per 1000 (95% CI 9 to 36 per 1000). Non-rheumatic cardiac abnormalities were found in 29 individuals. CONCLUSIONS: There is a high burden of both rheumatic and non-rheumatic cardiac abnormalities in this population. Rates described in New Zealand are as high as lower-middle-income countries in Africa. Addressing knowledge gaps regarding the natural history of RHD detected by echocardiography in adults is a priority issue for the international RHD community.

Cytokine imbalance in acute rheumatic fever and rheumatic heart disease: Mechanisms and therapeutic implications.

Acute Rheumatic Fever (ARF) and Rheumatic Heart Disease (RHD) are autoimmune sequelae of Group A Streptococcus infection with significant global disease burden. The pathogenesis of these diseases is poorly understood, and no immune modulating therapies are available to stop progression from ARF to RHD. Cytokines and chemokines are immune signaling molecules critical to the development of autoimmune diseases. An increasing number of studies point to a central role for pro-inflammatory cytokines and chemokines in ARF and RHD pathogenesis, in particular IL-6, IL-8/CXCL8, and TNFα, which are elevated in circulation in both ARF and RHD patients. Histological studies of RHD valve tissue implicates Th1 and Th17 associated pro-inflammatory cytokines, chemokine CXCL9, and the fibrosis-associated cytokine TGF-ß in progressive cycles of inflammatory damage and fibrotic repair. Taken together, this suggests immune molecules contribute to both the acute inflammatory disease stage of ARF, as well as cardiac remodeling and valve dysfunction in RHD. Monoclonal antibody blockade of pro-inflammatory cytokines IL-6 and TNFα are approved therapies for many autoimmune diseases and the most successful immunomodulating therapies for rheumatoid arthritis. Current evidence suggests possible benefit for ARF patients from IL-6 and TNFα blockade, in particular to interrupt progression to RHD, and warrants immediate investigation.

The Treatment of Acute Rheumatic Fever: Novel Use of Hydroxychloroquine.

Hydroxychloroquine (HCQ) suppresses an interleukin-1ß-granulocyte-macrophage colony-stimulating factor cytokine axis, reported to be dysregulated in peripheral blood mononuclear cells of acute rheumatic fever patients ex vivo. We describe HCQ treatment for 2 patients with rheumatic carditis and a protracted inflammatory course. HCQ was associated with control of inflammatory markers, control of pericarditis in first patient and stabilization of progressive carditis in the second patient.

Systems immunology reveals a linked IgG3-C4 response in patients with acute rheumatic fever.

Acute rheumatic fever (ARF) and chronic rheumatic heart disease (RHD) are autoimmune sequelae of a Group A streptococcal infection with significant global mortality and poorly understood pathogenesis. Immunoglobulin and complement deposition were observed in ARF/RHD valve tissue over 50 years ago, yet contemporary investigations have been lacking. This study applied systems immunology to investigate the relationships between the complement system and immunoglobulin in ARF. Patients were stratified by C-reactive protein (CRP) concentration into high (≥10 µg mL-1 ) and low (<10 µg mL-1 ) groups to distinguish those with clinically significant inflammatory processes from those with abating inflammation. The circulating concentrations of 17 complement factors and six immunoglobulin isotypes and subclasses were measured in ARF patients and highly matched healthy controls using multiplex bead-based immunoassays. An integrative statistical approach combining feature selection and principal component analysis revealed a linked IgG3-C4 response in ARF patients with high CRP that was absent in controls. Strikingly, both IgG3 and C4 were elevated above clinical reference ranges, suggesting these features are a marker of ARF-associated inflammation. Humoral immunity in response to M protein, an antigen implicated in ARF pathogenesis, was completely polarized to IgG3 in the patient group. Furthermore, the anti-M-protein IgG3 response was correlated with circulating IgG3 concentration, highlighting a potential role for this potent immunoglobulin subclass in disease. In conclusion, a linked IgG3-C4 response appears important in the initial, inflammatory stage of ARF and may have immediate utility as a clinical biomarker given the lack of specific diagnostic tests currently available.

Inter-rater and intra-rater reliability and agreement of echocardiographic diagnosis of rheumatic heart disease using the World Heart Federation evidence-based criteria.

OBJECTIVE: Different definitions have been used for screening for rheumatic heart disease (RHD). This led to the development of the 2012 evidence-based World Heart Federation (WHF) echocardiographic criteria. The objective of this study is to determine the intra-rater and inter-rater reliability and agreement in differentiating no RHD from mild RHD using the WHF echocardiographic criteria. METHODS: A standard set of 200 echocardiograms was collated from prior population-based surveys and uploaded for blinded web-based reporting. Fifteen international cardiologists reported on and categorised each echocardiogram as no RHD, borderline or definite RHD. Intra-rater and inter-rater reliability was calculated using Cohen's and Fleiss' free-marginal multirater kappa (κ) statistics, respectively. Agreement assessment was expressed as percentages. Subanalyses assessed reproducibility and agreement parameters in detecting individual components of WHF criteria. RESULTS: Sample size from a statistical standpoint was 3000, based on repeated reporting of the 200 studies. The inter-rater and intra-rater reliability of diagnosing definite RHD was substantial with a kappa of 0.65 and 0.69, respectively. The diagnosis of pathological mitral and aortic regurgitation was reliable and almost perfect, kappa of 0.79 and 0.86, respectively. Agreement for morphological changes of RHD was variable ranging from 0.54 to 0.93 κ. CONCLUSIONS: The WHF echocardiographic criteria enable reproducible categorisation of echocardiograms as definite RHD versus no or borderline RHD and hence it would be a suitable tool for screening and monitoring disease progression. The study highlights the strengths and limitations of the WHF echo criteria and provides a platform for future revisions.

Normal echocardiographic mitral and aortic valve thickness in children.

OBJECTIVE: We aimed to define the normal range of aortic and mitral valve thickness in healthy schoolchildren from a high prevalence rheumatic heart disease (RHD) region, using a standardised protocol for imaging and measurement. METHODS: Measurements were performed in 288 children without RHD. Anterior mitral valve leaflet (AMVL) thickness measurements were performed at the midpoint and tip of the leaflet in the parasternal long axis (PSLA) in diastole, when the AMVL was approximately parallel to the ventricular septum. Thickness of the aortic valve was measured from PSLA imaging in systole when the leaflets were at maximum excursion. The right coronary and non-coronary closure lines of the aortic valve were measured in diastole in parasternal short axis (PSSA) imaging. Results were compared with 51 children with RHD classified by World Heart Federation diagnostic criteria. RESULTS: In normal children, median AMVL tip thickness was 2.0 mm (IQR 1.7-2.4) and median AMVL midpoint thickness 2.0 mm (IQR 1.7-2.4). The median aortic valve thickness was 1.5 mm (IQR 1.3-1.6) in the PSLA view and 1.4 mm (IQR 1.2-1.6) in the PSSA view. The interclass correlation coefficient for the AMVL tip was 0.85 (0.71 to 0.92) and for the AMVL midpoint was 0.77 (0.54 to 0.87). CONCLUSIONS: We have described a standardised method for mitral and aortic valve measurement in children which is objective and reproducible. Normal ranges of left heart valve thickness in a high prevalence RHD population are established. These results provide a reference range for school-age children in high prevalence RHD regions undergoing echocardiographic screening.

Rheumatic fever with severe carditis: still prevalent in the South West Pacific.

Rheumatic heart disease (RHD) has a worldwide prevalence of 33 million cases and 270 000 deaths annually, making it the most common acquired heart disease in the world. There is a disparate global burden in developing countries. This case report aims to address the minimal RHD coverage by the international medical community. A Tahitian boy aged 10 years was diagnosed with advanced heart failure secondary to RHD at a local clinic. Previous, subtle symptoms of changes in handwriting and months of fever had gone unrecognised. Following a rapid referral to the nearest tertiary centre in New Zealand, urgent cardiac surgery took place. He returned home facing lifelong anticoagulation. This case highlights the RHD burden in Oceania, the limited access to paediatric cardiac services in countries where the RHD burden is greatest and the need for improved awareness of RHD by healthcare professionals, and the general public, in endemic areas.

Acute Rheumatic Fever After Group A Streptococcus Pyoderma and Group G Streptococcus Pharyngitis.

A case of acute rheumatic fever (ARF) in an Indigenous Maori child in New Zealand after Group A Streptococcus pyoderma and Group G Streptococcus pharyngitis is reported. The case demonstrates that ARF can develop in the absence of GAS pharyngitis and highlights a need for further research into the role of pyoderma and non-Group A Streptococci infections in ARF pathogenesis.

Association study involving polymorphisms in IL-6, IL-1RA, and CTLA4 genes and rheumatic heart disease in New Zealand population of Maori and Pacific ancestry.

INTRODUCTION: Rheumatic fever (RF) incidence among New Zealand (NZ) individuals of Polynesian (Maori and Pacific) ancestry remains among the highest in the world. Polymorphisms in the IL-6, IL1RN, and CTLA4 genes have been associated with RF, and their products are modulated by new medications. Confirmation of these previous associations could help guide clinical approaches. We aimed to test IL-6, IL-1RA (IL1RN), and CTLA4 functional SNPs in 204 rheumatic heart disease (RHD) patients and 116 controls of Maori and Pacific ancestry. MATERIAL AND METHOD: Self-reported ancestry of the eight great-grandparents defined ancestry of participants. Severity of carditis was classified according to the 2012 World Heart Federation guideline for the echocardiographic diagnosis of RHD. The IL-6 promoter rs1800797, IL1RN rs447713 and CTLA4 rs3087243 SNPs were genotyped by Taqman. Correlations were assessed by logistic regression analysis adjusting for gender and ancestry. RESULTS: The IL-6 rs1800797 variant was significantly associated with RHD with carriers of the GG genotype 6.09 (CI 1.23; 30.23) times more likely to develop RHD than the carriers of the AA genotype (P=0.027). No significant associations with RHD were found for the IL1RN rs447713 and CTLA4 rs3087243 SNPs. Patients carrying the G allele (GG plus AG genotype) for the IL1RN rs447713 SNP had 2.36 times (CI 1.00; 5.56) more severe carditis than those without this allele (the AA genotype) (P=0.049). CONCLUSION: The IL-6 promoter rs1800797 (-597G/A) SNP may influence susceptibility to RHD of people of Maori and Pacific ancestry living in NZ. The IL1RN rs447713 SNP may influence the severity of carditis in this population.

Focused cardiac ultrasound screening for rheumatic heart disease by briefly trained health workers: a study of diagnostic accuracy.

BACKGROUND: Echocardiographic screening for rheumatic heart disease (RHD) can identify individuals with subclinical disease who could benefit from antibiotic prophylaxis. However, most settings have inadequate resources to implement conventional echocardiography and require a feasible, accurate screening method. We aimed to investigate the accuracy of screening by non-expert operators using focused cardiac ultrasound (FoCUS). METHODS: In this prospective study of diagnostic accuracy, we recruited schoolchildren aged 5 to 15 years in Fiji to undergo two blinded tests. The index test was a FoCUS assessment of mitral and aortic regurgitation, performed by nurses after an 8-week training programme. The reference standard was the diagnosis of RHD by a paediatric cardiologist, based on a standard echocardiogram performed by a skilled echocardiographer. The primary outcome was the accuracy of the index test with use of the most sensitive criteria (any regurgitation). FINDINGS: We included 2004 children in the study. The index tests were done between September, 2012, and September, 2013, by seven nurses in eight schools in Fiji. The diagnostic accuracy of the screening test (area under receiver operator characteristic curve) was 0·89 (95% CI 0·83-0·94). When the primary cut-off point (any regurgitation) was used for analysis, sensitivity was 84·2% (72·1-92·5) and specificity was 85·6% (83·9-87·1). The sensitivity of individual nurses ranged from 66·7% to 100% and specificity 74·0% to 93·7%. INTERPRETATION: Screening by briefly trained nurses using FoCUS was accurate for the diagnosis of RHD. Refinements to training and screening test methods should be studied in a range of settings, and in parallel with investigations of the long-term clinical and cost-effectiveness of screening for RHD. FUNDING: Cure Kids, New Zealand; the Fiji Water Foundation provided funding for portable ultrasound equipment; see acknowledgments for further details of funders.

Screening for rheumatic heart disease: quality and agreement of focused cardiac ultrasound by briefly trained health workers.

BACKGROUND: Echocardiographic screening for rheumatic heart disease (RHD) has the potential to detect subclinical cases for secondary prevention, but is constrained by inadequate human resources in most settings. Training non-expert health workers to perform focused cardiac ultrasound (FoCUS) may enable screening at a population-level. We aimed to evaluate the quality and agreement of FoCUS for valvular regurgitation by briefly trained health workers. METHODS: Seven nurses participated in an eight week training program in Fiji. Nurses performed FoCUS on 2018 children aged five to 15 years, and assessed any valvular regurgitation. An experienced pediatric cardiologist assessed the quality of ultrasound images and measured any recorded regurgitation. The assessment of the presence of regurgitation and measurement of the longest jet by the nurse and cardiologist was compared, using the Bland-Altman method. RESULTS: The quality of FoCUS overall was adequate for diagnosis in 96.6%. There was substantial agreement between the cardiologist and the nurses overall on the presence of mitral regurgitation (κ = 0.75) and aortic regurgitation (κ = 0.61) seen in two views. Measurements of mitral regurgitation by nurses and the cardiologist were similar (mean bias 0.01 cm; 95% limits of agreement -0.64 to 0.66 cm). CONCLUSIONS: After brief training, health workers with no prior experience in echocardiography can obtain adequate quality images and make a reliable assessment on the presence and extent of valvular regurgitation. Further evaluation of the imaging performance and accuracy of screening by non-expert operators is warranted, as a potential population-level screening strategy in high prevalence settings.

Ventricular Function Before and After Surgery for Isolated and Combined Regurgitation in the Young.

BACKGROUND: Chronic mitral and aortic regurgitation (MR and AR) are associated with progressive contractile dysfunction. In the young, the risk of left ventricle (LV) dysfunction after operation for isolated and combined AR and MR is poorly defined. We aimed to compare LV mechanics in children and young adults with isolated and combined AR and MR, and identify risk factors for LV dysfunction after valve surgery. METHODS: Echocardiograms from children and young adults undergoing surgery for isolated severe AR (group I, n = 14), MR (group II, n = 21), or combined AR and MR (group III, n = 13), before and up to 18 months after surgery were compared with a normal population (n = 89). Normalized measures of LV geometry and mechanics were expressed as z scores. RESULTS: Before surgery all groups had LV dilatation, while groups I and III had afterload elevation and LV dysfunction. After operation LV dysfunction was more common in group III than in groups I and II (11 [84.5%] vs 5 [35.7%] vs 12 [57.1%], p = 0.04). The preoperative end-systolic volume z score predicted LV dysfunction after surgery in group I and II patients (p = 0.047, area under the curve = 0.75) but not in group III, where moderate LV dysfunction was related to the preoperative stress velocity index (-2.6 with vs -1.1 without, p = 0.04). CONCLUSIONS: Left ventricular mechanics in combined AR and MR closely resemble those of AR. End-systolic volume predicts postoperative LV dysfunction in patients with isolated valve regurgitation, while those with combined disease were at high risk of postoperative LV dysfunction.

Valvular Regurgitation Using Portable Echocardiography in a Healthy Student Population: Implications for Rheumatic Heart Disease Screening.

BACKGROUND: There is increasing use of portable echocardiography as a screening test for rheumatic heart disease (RHD). The prevalence of valvular regurgitation in healthy populations as determined using portable echocardiography has not been well defined. Minimal echocardiographic criteria for RHD have recently been clarified, but the overlap of normal and abnormal valvular regurgitation warrants further study. The aim of this study was to determine the spectrum of echocardiographic findings using portable echocardiography in children from a population with low prevalence of RHD. METHODS: Screening echocardiography was conducted in 396 healthy students aged 10 to 12 years using portable echocardiographic equipment. Echocardiograms were assessed according to 2012 World Heart Federation criteria for RHD. The prevalence of physiologic valvular regurgitation was compared with that found in previous studies of children using large-platform machines. RESULTS: Physiologic mitral regurgitation (MR) was present in 14.9% of subjects (95% CI, 11.7%-18.7%) and pathologic MR in 1.3% (95% CI, 0.6%-2.9%). Two percent (95% CI, 1.0%-3.9%) had physiologic aortic regurgitation, and none had pathologic aortic valve regurgitation. Physiologic tricuspid regurgitation was present in 72.7% of subjects (95% CI, 68.1%-76.9%) and physiologic pulmonary regurgitation in 89.6% (95% CI, 85.7%-91.8%). After cardiology review, no cases of definite RHD were found, but 0.5% of patients (95% CI, 0.1%-1.8%) had pathologic MR meeting World Heart Federation criteria for borderline RHD. Two percent (95% CI, 1.4%-4.6%) of the cohort had minor forms of congenital heart disease. CONCLUSIONS: The spectrum of physiologic cardiac valvular regurgitation in healthy children as determined using portable echocardiography is described and is within the range of previous studies using large-platform echocardiographic equipment. The finding of two children with pathologic-grade MR, likely representing the upper limit of physiologic regurgitation, has implications for echocardiographic screening for RHD in high-prevalence regions.

Mitral valve geometry in paediatric rheumatic mitral regurgitation.

Rheumatic mitral valve disease is associated with valvulitis and valvular regurgitation; however, the effect of the rheumatic process on the mitral valve geometry and function is not well understood. To assess mitral valve annulus remodelling in rheumatic mitral valve disease, 16 subjects aged 6-15 years with rheumatic mitral valve regurgitation [MR] [6 mild or moderate (Group 1), 10 severe (Group 2)] and 7 age- and body size-matched normal controls with adequate trans-thoracic echocardiograms were recruited. None of the patients had undergone surgical intervention and none had more than mild aortic regurgitation. None of the patients had mitral stenosis. 3D mitral valve geometry was assessed using a Tomtec system. The non-planar angle was increased in all subjects during early (control 147° ± 10, Group 1 168° ± 9, Group 2 166° ± 10; p < 0.05) and late systole (control 149° ± 12, Group 1 162° ± 10, Group 2 164° ± 6; p < 0.05), indicating loss of saddle shape. 2D annular area increased in Group 2 (control 397 ± 48 mm(2)/m(2) vs Group 2 739 ± 207, p < 0.05) with no significant change in annular perimeter indicating leaflet effacement. Mitral valve area correlated with left ventricular size (p < 0.001, r (2) = 0.74). There was no significant change in valve area and perimeter between early and late systole. Remodelling of the mitral valve apparatus in childhood rheumatic heart disease results in abnormal annular geometry. The mitral valve loses its saddle shape regardless of the severity of MR. This may be a consequence of inflammation on the fibrous trigones and surrounding annulus. In contrast, annular area enlargement occurs as a result of leaflet effacement and relates to MR severity and LV size.

New Zealand guidelines for the diagnosis of acute rheumatic fever: small increase in the incidence of definite cases compared to the American Heart Association Jones criteria.

AIM: The aim of the study was to compare utilisation of the New Zealand guidelines for the diagnosis of acute rheumatic fever (ARF) compared to the American Heart Association Jones criteria in a cohort of children METHOD: Retrospective review of 79 consecutive hospital diagnosed cases of ARF referred for secondary penicillin prophylaxis. The 2006 New Zealand guidelines for ARF were applied to the cohort and the diagnostic classification compared to classification using the American Heart Association 1992 Jones criteria. Cases were defined as definite, probable, possible or not ARF. The New Zealand guidelines use subclinical (echocardiographic) carditis as a major criterion of ARF. Monoarthritis, if associated with anti-inflammatory medicine usage likely preventing polyarthritis, is also accepted as a major criterion. RESULTS: Sixty-six cases were considered to be possible, probable or definite first episode of occurrence ARF. Utilisation of the New Zealand guidelines resulted in 16% (CL 7-29%) more cases defined as definite ARF than using American Heart Association 1992 Jones criteria (59/66 cases vs 51/66 cases). Polyathritis was the most frequent presenting symptom. Of those classified as definite ARF, 11% had monoarthritis with anti-inflammatory usage. Clinical carditis was present in 55% and subclinical carditis in 30%. The utilisation of subclinical carditis as a major criterion influenced the diagnosis to become definite ARF in 8% of the cohort only, as the remainder had polyarthritis or Sydenham's chorea as a major criterion. CONCLUSION: Utilisation of New Zealand guidelines for the diagnosis of ARF result in a modest increase (16%) in cases classified as definite ARF compared to the 1992 Jones criteria.

Pilot study of nurse-led rheumatic heart disease echocardiography screening in Fiji--a novel approach in a resource-poor setting.

We designed a pilot study of a training module for nurses to perform rheumatic heart disease echocardiography screening in a resource-poor setting. The aim was to determine whether nurses given brief, focused, basic training in echocardiography could follow an algorithm to potentially identify cases of rheumatic heart disease requiring clinical referral, by undertaking basic two-dimensional and colour Doppler scans. Training consisted of a week-long workshop, followed by 2 weeks of supervised field experience. The nurses' skills were tested on a blinded cohort of 50 children, and the results were compared for sensitivity and specificity against echocardiography undertaken by an expert, using standardised echocardiography definitions for definite and probable rheumatic heart disease. Analysis of the two nurses' results revealed that when a mitral regurgitant jet length of 1.5 cm was used as the trigger for rheumatic heart disease identification, they had a sensitivity of 100% and 83%, respectively, and a specificity of 67.4% and 79%, respectively. This pilot supports the principle that nurses, given brief focused training and supervised field experience, can follow an algorithm to undertake rheumatic heart disease echocardiography in a developing country setting to facilitate clinical referral with reasonable accuracy. These results warrant further research, with a view to developing a module to guide rheumatic heart disease echocardiographic screening by nurses within the existing public health infrastructure in high-prevalence, resource-poor regions.

Normalized end-systolic volume and pre-load reserve predict ventricular dysfunction following surgery for aortic regurgitation independent of body size.

Pre-operative end-systolic volume (ESV) is predictive of outcome after surgery for severe aortic regurgitation. ESV is influenced by body size and reflects function and afterload, but not pre-load. Left ventricular (LV) chamber size and function were measured in 40 patients (ages 10 to 64 years) by echocardiography before and 7 months after operation and expressed as z-scores in addition to simple indexing. A functional pre-load index, a marker of pre-load reserve, was calculated. Independent risk factors for post-operative LV dysfunction included higher post-operative ESV z-score (odds ratio [OR]: 3.3, p = 0.006) and lower functional pre-load index (OR: 0.3, p = 0.03). ESV per square meter had similar power to the ESV z-score. The ESV uncorrected for body size underestimated risk in smaller patients and overestimated risk in larger patients (p < 0.002). Pre-load reserve is an independent risk factor for LV dysfunction after aortic valve surgery in patients with severe aortic regurgitation. Failure to correct ESV for body size introduces systematic bias to risk assessment.