Novel Cardiac Magnetic Resonance Feature Tracking (CMR-FT) Analysis for Detection of Myocardial Fibrosis in Pediatric Hypertrophic Cardiomyopathy.

Myocardial fibrosis is a risk factor for sudden cardiac death in hypertrophic cardiomyopathy (HCM) and is conventionally identified by cardiac magnetic resonance imaging (CMR) using late gadolinium enhancement (LGE). This study evaluates utility of a novel 16-segment CMR feature tracking (CMR-FT) technique for measuring left ventricular (LV) strain (S) and strain rate (SR) on non-contrast cine images to detect myocardial fibrosis in pediatric HCM. We hypothesized that CMR-FT-derived S and SR will accurately differentiate HCM patients with and without myocardial fibrosis. Consecutive children with HCM who underwent CMR with LGE at our institution from 2006 to 2014 were included. Global and regional longitudinal, radial and circumferential S and SR of the LV in 2D and 3D were obtained using a CMR-FT software. Comparisons were made between HCM patients with (+LGE) and without (-LGE) delayed enhancement. Of the 29 HCM patients (mean age 13.5 ± 6.1 years; 52 % males), 11 (40 %) patients (mean age 17.5 ± 8.4 years) had +LGE. Global longitudinal, circumferential and radial S and SR were lower in +LGE compared to -LGE patients, in both 2D and 3D. Regional analysis revealed lower segmental S and SR in the septum with fibrosis compared to free wall without fibrosis. A global longitudinal S of ≤ -12.8 had 91 % sensitivity and 89 % specificity for detection of LGE. In pediatric HCM patients with myocardial fibrosis, global LV longitudinal, circumferential and radial S and SR were reduced, specifically in areas of fibrosis. A global longitudinal S of ≤ -12.8 detected patients with fibrosis with high degree of accuracy. This novel CMR-FT technique may be useful to identify myocardial fibrosis and risk-stratify pediatric HCM without use of contrast agents.

Screening for Congenital Heart Disease in Infants with Down Syndrome: Is Universal Echocardiography Necessary?

Current guidelines recommend that all neonates with Down syndrome (DS) be screened for congenital heart disease (CHD) with an echocardiogram. We sought to determine the effectiveness of a more accessible and less expensive screening strategy consisting of physical examination, electrocardiogram (ECG), and chest X-ray. The Intermountain Healthcare Enterprise Data Warehouse was used to identify infants with a positive karyotype for DS who were born between January 1, 2000, and June 30, 2012. Infants with the results of an echocardiogram, physical examination, ECG, and chest X-ray documented at age ≤6 months were included. Infants with an abnormality on physical examination, ECG, or chest X-ray were considered to have a positive screen. Echocardiography was the gold standard for calculating sensitivity, specificity, positive and negative predictive values for major CHD, defined as any heart defect that would typically require intervention during early childhood. Of 408 eligible infants, 240 (59 %) had major CHD, of whom 228 (95 %) had a positive screen. Screening missed eight infants with moderate/large patent ductus arteriosus and four infants with a moderate/large atrial septal defect. In 11 of these infants, the defect resolved spontaneously by age ≤4 months. One infant had a moderate atrial septal defect persisting at 2-year follow-up. Sensitivity and specificity of the screening for detecting CHD were 95 % (CI 92-98 %) and 41 % (CI 32-47 %); positive and negative predictive values were 69 % (CI 63-73 %) and 85 % (CI 75-92 %). Screening with physical examination, ECG, and chest X-ray is an effective method of identifying which infants with DS should have an echocardiogram. This method would have resulted in 69 (17 %) fewer echocardiograms without missing infants with major CHD.

Phenotype of a patient with contiguous deletion of TBX5 and TBX3: expanding the disease spectrum.

The important roles that T-box genes play in the morphogenesis of the heart and its conduction system has long been established, and a number of disorders are linked to mutations in these T-box genes. Holt-Oram syndrome (HOS), the classic heart and hand syndrome, is clinically typified by radial ray upper limb abnormalities and cardiac malformations, and is caused by mutations involving TBX5. Another member of the T-box gene family, TBX3, is found in close proximity to TBX5 on chromosome 12q24. Mutations in TBX3 cause ulnar-mammary syndrome (UMS), which is distinguished by upper limb malformations affecting the ulnar ray, apocrine, and mammary gland hypoplasia, and genital defects. While disorders involving isolated mutations of TBX5 and TBX3 have been well described, contiguous deletions of these T-box genes remain exceptional. We report on a patient with features of both HOS and UMS consisting of bilateral symmetric limb malformations, congenital cardiac defects, and rapidly progressive cardiac conduction disease.