Do we need MR conditional pacemakers?

Magnetic resonance imaging (MRI) is a widely accepted tool for the diagnosis of a variety of disease states. However, due to safety concerns the presence of an implanted cardiac pacemaker is considered to be a contraindication to MRI in most medical centres. The increasing number of implanted pacemakers and the estimated over 50% probability that a pacemaker patient may be a candidate for an MRI increase the need for safe scanning of pacemaker patients. Over the last ten years a major effort has been made to understand the potential risks. The influences from the three electromagnetic fields on pacemakers are versatile and will be summarised. The research in this area has helped to predict the risks of an MRI scan in patients with conventional pacemakers, and has also stimulated pacemaker manufacturers to improve their devices with the goal of providing MR conditional devices. Since autumn 2008 the first approved MR conditional pacemakers have been on the market and other devices are likely to follow this trend. However, the vast majority of devices are still not approved for MRI, a situation which will take several years to change. It is thus important that a solution be also found for these patients. Several studies including over 500 patients with a pressing need for MRI have been performed at different experienced centres. On the basis of those data various organisations in MRI fields have proposed guidelines for MRI in patients who fulfill given requirements. However, at present, non- MRI modalities should be considered, whenever possible, for diagnosis in pacemaker recipients with conventional devices. If other imaging modalities are not adequate, MRI with careful monitoring and preparation for adverse events may be considered only at experienced centres. With the wider availability of MR conditional devices, the risks of MRI are greatly reduced and non-tertiary centres will be able to perform these investigations. In any case, rapid progress in the field of MR conditional pacing is desirable

Pattern and outcome of admissions as seen in the paediatric emergency ward of the Niger Delta University Teaching Hospital Bayelsa State, Nigeria

Objective: To describe the pattern and outcome of childhood illnesses seen in a paediatric emergency ward of a tertiary centre in the Niger Delta region of Nigeria.Methods: Admission records of all children seen in the Children’s Emergency Ward (CHEW) between the 1st of January 2008 and 31st ofDecember 2011 were retrospectively reviewed and analysed.Results: A total of 1756 children were admitted into the emergency ward over a four year period (1st January 2008 to 31st December 2011). The age range was one month to 18 years with a mean of 36.6 months. There was a male preponderance with a male to female ratio of 1.4:1. Majority, 1386 (78.9%) of the patients were below the age of five years. The meanduration of stay was 2.2 days. The major causes of admission were malaria, 562 (32.0%), diarrhoeal disease 389 (22.2%), respiratory tract infections 162 (9.2%) and anaemic heart failure 112(6.4%). Peak admissions period and mortality were in the months of January, May and December. There were 799 transfers, 710 discharges, 94 discharges against medical advice and 20 referrals. Over the period, 133 children diedgiving a mortality rate of 7.6%. Major causes of mortality wereanaemic heart failure 32(24.1%), malaria 26 (19.6%), septicaemia 17(12.8%) and diarrhoeal disease 15 (11.3%).Conclusions: Infections are the major cause of morbidity and mortalityin the study environment with the under-fives being the most vulnerable.Key words: children, under-fives, emergency room, admissions, morbidity, mortalit

slq(2)sl_q(2) Realizations for Kepler and Oscillator Potentials and q-Canonical Transformations

The realizations of the Lie algebra corresponding to the dynamical symmetry group SO(2,1) of the Kepler and oscillator potentials are q-deformed. The q-canonical transformation connecting two realizations is given and a general definition for q-canonical transformation is deduced. q-Schr\"{o}dinger equation for a Kepler like potential is obtained from the q-oscillator Schr\"{o}dinger equation. Energy spectrum and the ground state wave function are calculated.Comment: 12 pages, Latex twice, (Comparison with the other approaches and some refs. added. The version which will appear in J. Phys. A

Endothelin and cardiac arrhythmias: do endothelin antagonists have a therapeutic potential as antiarrhythmic drugs?

Endothelin-1 (ET-1), the predominant isoform of the ET peptide family and a potent vasoconstrictor, has been shown to aggravate ischemia-induced ventricular arrhythmias. However, there is also evidence that ET-1 may have a direct arrhythmogenic action that is not solely attributable to myocardial ischemia. Proposed mechanisms for the arrhythmogenic effects of ET-1 are prolongation or increased dispersion of monophasic action potential duration, QT prolongation, development of early afterdepolarizations, acidosis, and augmentation of cellular injury. As for an ionic basis for the observed electrophysiologic effects, ET-induced Ca2+ release from intracellular stores, generation of inositol triphosphate, inhibition of delayed rectifier K+ current, and stimulation of the Na+/H+ exchanger may be involved. Recently, some studies have shown that ET receptor antagonists, which promise to be powerful tools in cardiovascular medicine, may also demonstrate antiarrhythmic properties. This review describes the current state of knowledge on the interactions between the ET system and cardiac arrhythmias, and discusses the therapeutic potential of ET antagonists as antiarrhythmic drug

Nightside ionosphere of Mars studied with local electron densities: A general overview and electron density depressions

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/95308/1/jgra21490.pd