Exercise capacity in children with isolated congenital complete atrioventricular block: does pacing make a difference?

Item does not contain fulltextThe management of patients with isolated congenital complete atrioventricular block (CCAVB) has changed during the last decades. The current policy is to pace the majority of patients based on a variety of criteria, among which is limited exercise capacity. Data regarding exercise capacity in this population stems from previous publications reporting small case series of unpaced patients. Therefore, we have investigated the exercise capacity of a group of contemporary children with CCAVB. Sixteen children (mean age 11.5 +/- 4; seven boys, nine girls) with CCAVB were tested. In 13 patients, a median number of three pacemakers were implanted, whereas in three patients no pacemaker was given. All patients had an echocardiogram and completed a cardiopulmonary cycle exercise test. Exercise parameters were determined and compared with reference values obtained from healthy Dutch peers. The peak oxygen uptake/body mass was reduced to 34.4 +/- 9.5 ml kg(-1) min(-1) (79 +/- 24% of predicted) and the ventilatory threshold was reduced to 52 +/- 17% of peak oxygen uptake (78 +/- 21% of predicted), whereas the peak work load/body mass was 2.8 +/- 0.6 W/kg (91 +/- 24% of predicted), which was similar to controls. Importantly, 25% of the paced patients showed upper rate restriction by the pacemaker. In conclusion, children with CCAVB show a reduced peak oxygen uptake and ventilatory threshold, whereas they show normal peak work rates. This indicates that they generate more energy during exercise from anaerobic energy sources. Paced children with CCAVB do not perform better than unpaced children.1 april 201

Global Spread of Norovirus GII.17 Kawasaki 308, 2014-2016

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Powder diffraction and synchrotron radiation.

Powder diffraction is one of the fundamental techniques for the investigation of materials. Its sensitivity to long range order makes it ideal for the identification, quantification and structural characterization of crystalline phases. Powder diffraction experiments performed at synchrotron sources make ample use of the intrinsic characteristics of synchrotron radiation in terms of energy tunability, brilliance, natural divergence, and excellent signal/noise ratio. Synchrotron radiation powder diffraction (SR-PD) enhances and optimizes the traditional applications of laboratory XRPD, such as phase identification, phase quantification, texture analysis, and peak broadening analysis in terms of stress/strain. However, the properties of the synchrotron X-rays also allow a number of experiments not accessible with laboratory sources, especially in terms of time-resolution, the use of non-ambient sample environments, and simultaneous and combined experiments. The mapping of the physical, chemical, and crystallographic properties of the sample in 2D and 3D using smart combinations of diffraction imaging spectroscopy is the natural current evolution of many synchrotron instruments, and one that is bound to have a great impact on many aspects of materials studies