Search

Pulmonary vein isolation (PVI) is central to ablation approaches for atrial fibrillation (AF), yet many patients still have arrhythmia recurrence after one or more procedures despite the latest technology for PVI. Ablation of rotational or focal sources for AF, which lie outside the pulmonary veins in many patients, is a practical approach that has been shown to improve success by many groups. Localized sources lie in atrial regions shown mechanistically to sustain AF in optical mapping and clinical studies of human AF, as well as computational and animal studies. Because they arise in localized atrial regions, AF sources may explain central paradoxes in clinical practice – such as how limited ablation in patient specific sites can terminate persistent AF yet extensive anatomical ablation at stereotypical locations, which should extinguish disordered waves, does not improve success in clinical trials. Ongoing studies may help to resolve many controversies in the field of rotational sources for AF. Studies now verify rotational activation by multiple mapping approaches in the same patients, at sites where ablation terminates persistent AF. However, these studies also show that certain mapping methods are less effective for detecting AF sources than others. It is also recognized that the success of AF source ablation is technique dependent. This review article provides a mechanistic and clinical rationale to ablate localized sources (rotational and focal), and describes successful techniques for their ablation as well as pitfalls to avoid. We hope that this review will serve as a platform for future improvements in the patient-tailored ablation for complex arrhythmias. Keywords: Atrial fibrillation, Ablation, Rotors, Computer, Mapping

Global survey of transcriptome dynamics can provide molecular insights into cell physiology. In the past few years, DNA microarray for transcriptome analysis has been augmented by high-throughput sequencing methods; extending the reach of transcriptome analysis to the rodent species of biotechnological importance, for which the development of genomic tools has been lagging. The rapid accumulation of sequencing data for these species highlighted the need for more evidence-based annotation. Recent findings in the epigenetic regulation in human and mouse will inspire similar research in CHO and BHK cells. Transcriptome studies in these recombinant cells will likely lay the foundation for a systems-based genome engineering which can be used to develop superior producing cell lines. Herein, we summarized the recent findings and advances in transcriptome studies of cell culture bioprocesses. The potential impact of transcriptomics on biopharmaceutical process technology is also discussed., (Copyright © 2014 Elsevier Ltd. All rights reserved.)