Atrial surface geometry was identified and myofiber orientations were estimated throughout by eigen-analysis of the 3-D image structure tensor. Sinus node, crista terminalis, pectinate muscle, Bachman’s bundle, and pulmonary veins were segmented on the basis of anatomic characteristics. Heterogeneous electrical properties were assigned to this structure and electrical activation was simulated on it at 100 mu m(3) resolution, selleckchem using both biophysically-detailed and reduced-order cell activation models with spatially-varying membrane kinetics. We

confirmed that the model reproduced key features of the normal spread of atrial activation. Furthermore, we demonstrate that vulnerability to rhythm disturbance caused by structural heterogeneity in the posterior left atrium is exacerbated by spatial variation of repolarization kinetics across this region. These results provide insight into mechanisms that may sustain paroxysmal atrial fibrillation. We conclude that image-based computer models that incorporate realistic descriptions of atrial myofiber architecture and electrophysiologic properties have the potential to analyse and identify complex substrates for atrial fibrillation.”
“Over 20 years ago the term non-specific

low back pain became popular to convey the limitations of our knowledge of the pathological source of most people’s low back pain. Knowledge of underlying pathology has advanced little since then, despite limited improvements in outcomes for patients with low back pain.

This paper discusses potential misunderstandings related to diagnostic studies in Apoptosis inhibitor check details the field of low back pain and argues that future diagnostic studies should include and investigate pathological sources of low back pain.

Six potential misunderstandings are discussed. (1) Until diagnosis is shown

to improve outcomes it is not worth investigating; (2) without a gold standard it is not possible to investigate diagnosis of low back pain; (3) the presence of pathology in some people without low back pain means it is not important; (4) dismissal of the ability to diagnose low back pain in clinical guidelines is supported by the same level of evidence as recommendations for therapy; (5) suggesting use of a diagnostic test in research is misinterpreted as endorsing its use in current clinical practice; (6) we seem to have forgotten the ‘bio’ in biopsychosocial low back pain.

We believe the misunderstandings presented in this paper partly explain the lack of investigation into pathology as an important component of the low back pain experience. A better understanding of the biological component of low back pain in relation, and in addition, to psychosocial factors is important for a more rational approach to management of low back pain.”
“Aortic valve reconstruction with fixed pericardium may occasionally be very useful when treating children with aortic valve disease.