Three-dimensional echocardiography of congenital abnormalities of the left atrioventricular valve

Familial Mitral Arcade, Tricuspid Dysplasia, Left Ventricular Noncompaction and Short-Chain Acyl-CoA Reductase Deficiency

Mitral arcade is a rare entity that is mostly reported in pediatric patients. We present the first 2 adult cases of mitral arcade in combination with tricuspid dysplasia, left ventricular noncompaction, and short-chain acyl-CoA deficiency in 2 brothers. We examined clinical and echocardiographic data on 2 brothers with a combination of short-chain acyl-CoA deficiency, mitral arcade, tricuspid dysplasia, and left ventricular noncompaction (LVNC), highlighting their clinical course and outcomes. Two-dimensional and 3-dimensional transthoracic echocardiography revealed direct attachment of the papillary muscles to the mitral leaflets, namely mitral arcade, as well as mild mitral regurgitation along with LVNC and tricuspid dysplasia. Over the past 7 years, both brothers have remained asymptomatic with excellent exercise capacity (13 and 10 metabolic equivalents (METS), respectively). Mitral and tricuspid regurgitation remain mild with unchanged left ventricular function (ejection fraction: 65% and 59%). In conclusion, we highlight 2 cases with a constellation of pathology including short-chain acyl-CoA deficiency, mitral arcade, tricuspid dysplasia, and LVNC, which has never been described before.

Echocardiographic examination of mitral valve abnormalities in the paediatric population: current practices

We reviewed the recent literature for echocardiographic assessment of mitral valve abnormalities in children. A literature search was performed within the National Library of Medicine using the keywords "mitral regurgitation and/or stenosis, children." The search was refined by adding the keywords "echocardiographic definition, classification, and evaluation." Thirty-one studies were finally included. Significant advances in echocardiographic imaging of mitral valve defects, mainly due to the implementation of three-dimensional technology, contribute to a better understanding of the underlying anatomy. However, heterogeneity between classification systems of mitral valve disease severity is a serious problem. For regurgitant lesions, there is only very limited evidence from small studies that support the adoption of quantitative/semi-quantitative indexes commonly employed in adults. Despite the lack of evidence base, qualitative evaluation of regurgitation severity is often employed. For stenotic lesions, no clear categorisation based on trans-valvular echocardiography-derived "gradients" has been consistently applied to define mild, moderate, or severe obstruction across different paediatric age ranges. Quantitative parameters such as valve area have also been poorly validated in children. Adult recommendations are frequently applied without validation for the paediatric age. In conclusion, significant advances in the anatomical evaluation of mitral valve diseases have been made, thanks to three-dimensional echocardiography; however, limitations remain in the quantitative/semi-quantitative estimation of disease severity, both with respect to valvular regurgitation and stenosis. Because adult echocardiographic recommendations should not be simply translated to the paediatric age, more specific paediatric guidelines and standards for the assessment of mitral valve diseases are needed.

EDUCATIONAL SERIES IN CONGENITAL HEART DISEASE: Three-dimensional echocardiography in congenital heart disease

Three-dimensional echocardiography is a valuable tool for the assessment of cardiac function where it permits calculation of chamber volume and function. The anatomy of valvar and septal structures can be presented in unique and intuitive ways to enhance surgical planning. Guidance of interventional procedures using the technique has now become established in many clinical settings. Enhancements of image processing to include intracavity flow, image fusion and true 3D displays look set to further improve the contribution of this modality to care of the patient with congenital heart disease.

Morphological three-dimensional analysis of papillary muscles in borderline left ventricles

OBJECTIVE

Mitral valve anatomy has a significant impact on potential surgical options for patients with hypoplastic or borderline left ventricle. Papillary muscle morphology is a major component regarding this aspect. The purpose of this study was to use cardiac magnetic resonance to describe the differences in papillary muscle anatomy between normal, borderline, and hypoplastic left ventricles.

METHODS

We carried out a retrospective, observational cardiac magnetic resonance study of children (median age 5.36 years) with normal (n=30), borderline (n=22), or hypoplastic (n=13) left ventricles. Borderline and hypoplastic cases had undergone an initial hybrid procedure. Morphological features of the papillary muscles, location, and arrangement were analysed and compared across groups.

RESULTS

All normal ventricles had two papillary muscles with narrow pedicles; however, 18% of borderline and 46% of hypoplastic cases had a single papillary muscle, usually the inferomedial type. In addition, in borderline or hypoplastic ventricles, the supporting pedicle occasionally displayed a wide insertion along the ventricular wall. The length ratio of the superolateral support was significantly different between groups (normal: 0.46±0.08; borderline: 0.39±0.07; hypoplastic: 0.36±0.1; p=0.009). No significant difference, however, was found when analysing the inferomedial type (0.42±0.09; 0.38±0.07; 0.39±0.22, p=0.39). The angle subtended between supports was also similar among groups (113°±17°; 111°±51° and 114°±57°; p=0.99). A total of eight children with borderline left ventricle underwent biventricular repair. There were no significant differentiating features for papillary muscle morphology in this subgroup.

CONCLUSIONS

The superolateral support can be shorter or absent in borderline or hypoplastic left ventricle cases. The papillary muscle pedicles in these patients often show a broad insertion. These changes have important implications on surgical options and should be described routinely.