Left ventricular remodelling in rheumatic heart disease - trends over time and implications for follow-up in childhood.

BACKGROUND: Rheumatic heart disease (RHD) is the most common form of acquired heart disease worldwide. In RHD, volume loading from mitral regurgitation leads to left ventricular (LV) dilatation, increased wall stress, and ultimately LV dysfunction. Improved understanding of LV dynamics may contribute to refined timing of intervention. We aimed to characterize and compare left ventricular remodelling between rheumatic heart disease (RHD) severity groups by way of serial echocardiographic assessment of volumes and function in children. METHODS: Children with RHD referred to Perth Children's Hospital (formally Princess Margaret Hospital) (1987-2020) were reviewed. Patients with longitudinal pre-operative echocardiograms at diagnosis, approximately 12 months and at most recent follow-up, were included and stratified into RHD severity groups. Left ventricular (LV) echocardiographic parameters were assessed. Adjusted linear mixed effect models were used to compare interval changes. RESULTS: 146 patients (median age 10 years, IQR 6-14 years) with available longitudinal echocardiograms were analysed. Eighty-five (58.2%) patients had mild, 33 (22.6%) moderate and 28 (19.2%) severe RHD at diagnosis. Mean duration of follow-up was 4.6 years from the initial diagnosis. Severe RHD patients had significantly increased end-systolic volumes (ESV) and end-diastolic volumes (EDV) compared to mild/moderate groups at diagnosis (severe versus mild EDV mean difference 27.05 ml/m2, p < 0.001, severe versus moderate EDV mean difference 14.95 ml/m2, p = 0.006). Mild and moderate groups experienced no significant progression of changes in volume measures. In severe RHD, LV dilatation worsened over time. All groups had preserved cardiac function. CONCLUSIONS: In mild and moderate RHD, the lack of progression of valvular regurgitation and ventricular dimensions suggest a stable longer-term course. Significant LV remodelling occurred at baseline in severe RHD with progression of LV dilatation over time. LV function was preserved across all groups. Our findings may guide clinicians in deciding the frequency and timing of follow-up and may be of clinical utility during further reiterations of the Australia and New Zealand RHD Guidelines.

Impact of mitral regurgitation on left ventricular remodeling and function in children with rheumatic heart disease.

The impact of mitral regurgitation (MR) from pediatric rheumatic heart disease (RHD) and its effect on left ventricular (LV) remodeling and function following surgical intervention is uncertain. The objective is to explore the impact of mitral valve (MV) surgeries on myocardial mechanics, remodeling and function and identify pre-operative predictors of post-operative dysfunction which may contribute to the optimal timing of intervention. A retrospective review of echocardiographic data was performed of eighteen pediatric patients with RHD (median 9yrs, IQR 6-12) who underwent MV surgery. Echocardiograms pre-operatively and a median of 13.5 months (IQR 10.2-15) following intervention were compared to controls. Pre-operative LV end-diastolic indexed volumes (LVEDVi) were significantly increased compared to controls and remained persistently larger post-operatively. LV ejection fraction (LVEF) (pre 62.6% ± 6.1, post 51.7% ± 9.7, p = 0.002), and global longitudinal strain (GLS) (pre - 24.3 ± 4.1, post - 18.2 ± 2.6, p < 0.001) decreased post-operatively at mid-term follow-up. Pre-operative LVEDVi was a significant predictor of post-operative LVEF, with a cut-off of ≥ 102 ml/m2 associated with LV dysfunction (LVEF < 55%; sensitivity 70%, specificity 75%). Pre-operative LVEDVi also negatively correlated with GLS (r = - 0.58, p = 0.01). LV dimensions and volumes remain persistently larger than controls while LV function decreases post-surgical alleviation of MR in paediatric RHD. Pre-operative LVEDVi predicted post-operative LV dysfunction and utilising LV indexed volumes in directing timing of surgical planning should be considered. Further studies are required to investigate whether timely alleviation of MR before significant LV dilatation and remodeling occur may substantially prevent LV dysfunction and improve outcomes.

The epidemiology and clinical features of Kawasaki disease in Australia.

OBJECTIVES: The current Australian epidemiology of Kawasaki disease (KD) is poorly defined. Previous enhanced surveillance (1993-1995) estimated an incidence of 3.7/100,000 <5 years. METHODS: We identified all patients hospitalized in Western Australia (current population ∼2.4 million) 1979 through 2009 with a discharge diagnosis of KD. We reviewed demographic, clinical, laboratory, and echocardiographic data from individual patient files and derived age-specific population estimates. KD diagnosis was made using standard criteria. RESULTS: There were 353 KD cases, with incomplete KD in 34 (9.6%). Male to female ratio was 1.7:1 and median age was 3.8 years (interquartile range 12-60 months). Fifty (18.1%) patients were Asian. Mean annual incidence increased from 2.82 per 100,000 children aged <5 years (95% confidence interval, 1.93-3.99) in 1980 to 1989, to 7.96 (6.48-9.67) in 1990 to 1999, to 9.34 (7.72-11.20) in 2000 to 2009. The highest incidence was 15.7 in 2005. A total of 293 children (83%) received intravenous immunoglobulin and 331 (95.4%) aspirin. Of 282 children who completed echocardiographic studies, 47 (16.7%) had coronary artery (CA) ectasia/dilatation and 19 (6.8%) had CA aneurysms; male gender was significantly associated with CA abnormalities. CONCLUSIONS: KD epidemiology in Western Australia mirrors that of other industrialized, predominantly European-Caucasian populations. The rising incidence likely reflects both improved ascertainment and a real increase in disease burden. The current Australian incidence is threefold higher than previously reported and similar to the United Kingdom. The CA outcomes, which include the pre-intravenous immunoglobulin era, are comparable to those reported elsewhere.

Value of tissue Doppler echocardiography in children with pulmonary hypertension.

BACKGROUND: The impact of pulmonary hypertension (PHT) on right ventricular and left ventricular (LV) function in children with PHT is unknown, and echocardiographic data combining conventional and Doppler tissue imaging (DTI) on PHT in children are sparse. METHODS: Forty-one children (18 male; mean age, 7.9 ± 5.6 years) with PHT and structurally normal hearts (27 with idiopathic PHT, 14 with associated PHT) and 44 age-matched healthy controls were assessed using conventional echocardiography and DTI. RESULTS: Children with PHT had enlarged tricuspid valve diameters, right atrial areas, pulmonary artery dimensions, and LV eccentricity indices. In addition, pulmonary acceleration time and tricuspid annular plane systolic excursion were significantly reduced in patients compared with controls. DTI revealed that children with PHT had significantly lower systolic (S) and early diastolic (E) velocities at the tricuspid and septal levels. Despite preserved LV ejection fractions, left lateral free wall systolic velocities were significantly reduced in patients with PHT. Significantly reduced LV rapid filling velocities (E) suggested an underloaded left ventricle or LV diastolic dysfunction in children with PHT compared with controls. Pulmonary acceleration time and tricuspid annular plane systolic excursion correlated best with DTI systolic tricuspid and septal velocities. CONCLUSIONS: Despite not being evident on conventional two-dimensional echocardiography, LV systolic performance appears to be impaired in children with PHT. Quantitative DTI assessment of ventricular function and ventricular-ventricular interactions in this setting might provide further insights into the mechanisms leading to end-stage PHT and may guide clinicians to optimize antifailure treatment.