The pediatric electrocardiogram part III: Congenital heart disease and other cardiac syndromes.
ABSTRACT Approximately 1% of newborns are affected by congenital heart disease (CHD), and although many lesions of CHD have trivial hemodynamic and clinical implications, some clinically significant lesions are asymptomatic in the immediate newborn period and may present after discharge from the well baby nursery. Because of this, CHD should be considered in the differential diagnosis of any ill-appearing newborn, regardless of the presence of cyanosis. In addition, the number of children, adolescents, and adults with surgically repaired or palliated CHD continues to grow within the United States and other developed countries. It is in this population that arrhythmias are particularly prone to develop, and knowledge of the common arrhythmias associated with CHD is mandatory for the acute care provider.
- Journal of Pediatric Health Care 06/2012; · 1.76 Impact Factor
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ABSTRACT: Down syndrome (DS) leads to complex phenotypes and is the main genetic cause of birth defects and heart diseases. The Ts65Dn DS mouse model is trisomic for the distal part of mouse chromosome 16 and displays similar features with post-natal lethality and cardiovascular defects. In order to better understand these defects, we defined electrocardiogram (ECG) with a precordial set-up, and we found conduction defects and modifications in wave shape, amplitudes, and durations in Ts65Dn mice. By using a genetic approach consisting of crossing Ts65Dn mice with Ms5Yah mice monosomic for the App-Runx1 genetic interval, we showed that the Ts65Dn viability and ECG were improved by this reduction of gene copy number. Whole-genome expression studies confirmed gene dosage effect in Ts65Dn, Ms5Yah, and Ts65Dn/Ms5Yah hearts and showed an overall perturbation of pathways connected to post-natal lethality (Coq7, Dyrk1a, F5, Gabpa, Hmgn1, Pde10a, Morc3, Slc5a3, and Vwf) and heart function (Tfb1m, Adam19, Slc8a1/Ncx1, and Rcan1). In addition cardiac connexins (Cx40, Cx43) and sodium channel sub-units (Scn5a, Scn1b, Scn10a) were found down-regulated in Ts65Dn atria with additional down-regulation of Cx40 in Ts65Dn ventricles and were likely contributing to conduction defects. All these data pinpoint new cardiac phenotypes in the Ts65Dn, mimicking aspects of human DS features and pathways altered in the mouse model. In addition they highlight the role of the App-Runx1 interval, including Sod1 and Tiam1, in the induction of post-natal lethality and of the cardiac conduction defects in Ts65Dn. These results might lead to new therapeutic strategies to improve the care of DS people.PLoS Genetics 05/2012; 8(5):e1002724. · 8.52 Impact Factor