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This study sought to determine the effect of contact force (CF) on atrial lesion size, quality, and transmurality by using a chronic porcine model of radiofrequency ablation.CF is a major determinant of ventricular lesion formation, but uncertainty exists regarding the most appropriate CF parameters to safely achieve permanent, transmural lesions in the atria.Intercaval linear ablation (30 W, 42°C, 17 ml/min irrigation) was performed in 8 Göttingen minipigs by using a force-sensing catheter with CF20 g (high force) or 10 g (low force) at alternate ends of the line, separated by an intentional gap. Voltage mapping and cardiovascular magnetic resonance (CMR) imaging were performed pre-ablation, immediately after ablation, and at 2 months' post-procedure. Lesions were sectioned orthogonal to the axis of ablation to assess transmurality.Mean CF was 22.6 ± 11.4 g and 7.8 ± 4.0 g in the high and low CF regions. Acute tissue edema was greater with high CF, both caudally (7.0 mm vs. 4.6 mm; p = 0.016) and cranially (6.9 mm vs. 4.6 mm; p = 0.038). There was no difference in chronic lesion size (voltage mapping) or volume (late gadolinium enhancement CMR) between high and low CF regions. There was no difference in scar density (assessed by low-voltage criteria and late gadolinium enhancement signal intensity) or histological transmurality between high and low CF regions.Although high CF (20 g) resulted in more acute tissue edema than low CF (10 g), chronically there was no difference in lesion size, quality, or transmurality. Appropriate CF targets for atrial ablation may be lower than previously thought.

Introduction: Patients and their carers find it difficult to access information following a stroke or transient ischaemic attack (TIA). To improve the provision of this information, the Royal College of Physicians' National Clinical Guideline for Stroke (4th edition, 2012) was accompanied by a booklet designed for patients and their carers. Dissemination of the information was enhanced with the development of smartphone applications that are freely available on both iOS and Android devices. Here we present a report into the use of these applications. Methods: The applications were designed to reflect the content of the booklet with the information primarily accessed via a scrollable index, with separate sections to provide information on support services available in the UK. Data on usage were anonymously collected during the first eight months following global release. The hypothesis that users would preferentially access information on particular topics was tested. Results: The smartphone applications were downloaded a total of 2,046 times (1,503 iOS and 543 Android), of which 61.3% was by individuals in the UK. Topics covering rehabilitation were most commonly accessed, accounting for 33.2% of all application usage. Within this category, ‘Care after a stroke or TIA (principles)’ represented 14.5% of use and ‘Sex after stroke’ represented 13.1%. The next most commonly accessed category was ‘Specialist early care’ with 25.0% of total application usage, of which the topic ‘Brain scan’ accounted for 24.5%. Overall, the most commonly accessed index item was titled ‘Stroke, what is it?’, and this represented 8.27% of total application usage. Within the category of support services, 45.6% of usage was directed towards accessing information on ‘Local health services and stroke clubs’. Conclusions: Smartphone applications are useful adjuncts for the dissemination of information to patients and their carers following a stroke or TIA. Users exhibit a preference for information on rehabilitation and specialist early care. Future publications should target these topics for more in-depth discussion.

Surface flattening in medical imaging has seen widespread use in neurology and more recently in cardiology to describe the left ventricle using the bull's-eye plot. The method is particularly useful to standardize the display of functional information derived from medical imaging and catheter-based measurements. We hypothesized that a similar approach could be possible for the more complex shape of the left atrium (LA) and that the surface flattening could be useful for the management of patients with atrial fibrillation (AF). We implemented an existing surface mesh parameterization approach to flatten and unfold 3D LA models. Mapping errors going from 2D to 3D and the inverse were investigated both qualitatively and quantitatively using synthetic data of regular shapes and computer tomography scans of an anthropomorphic phantom. Testing of the approach was carried out using data from 14 patients undergoing ablation treatment for AF. 3D LA meshes were obtained from magnetic resonance imaging and electroanatomical mapping systems. These were unfolded using the developed approach and used to demonstrate proof-of-concept applications, such as the display of scar information, electrical information and catheter position. The work carried out shows that the unfolding of complex cardiac structures, such as the LA, is feasible and has several potential clinical uses for the management of patients with AF.

As the population receiving cardiac device therapy ages, the number of extraction procedures performed in octogenarians is increasing. This group has more comorbidities and may be at higher risk of such procedures.Document the safety and success of percutaneous lead extraction in octogenarians.All extraction cases performed between January 2001 and April 2011 entered into a computer database were analyzed for patient characteristics and indications, extraction technique, procedural success, and complications. Success and complications were classified according to the Heart Rhythm Society consensus statement. Outcomes in octogenarians were compared to younger patients undergoing extraction during the same period.Four hundred and six cases were performed: 72 procedures in octogenarians (mean age 84, range 80-95) and 334 in younger adults (mean age 62, range 20-79). Octogenarians had a greater number of comorbidities per case. Infection was the commonest indication for extraction in both groups. One hundred forty-one leads were extracted in octogenarians and 657 in younger patients. Laser assistance was required in 51.4% of octogenarians versus 49.7% of younger patients. Procedural success was achieved in 71/72 (98.6%) octogenarians versus 329/334 (98.5%) younger patients. No procedural mortality occurred in either group. Overall, complications were more frequent in octogenarians with major and minor complications occurring in 2.8 and 8.3% of octogenarians versus 0.6 and 3.0% of younger patients (P = 0.014).Procedural success was equally high in octogenarians and younger patients. Percutaneous lead extraction can be performed effectively and safely in octogenarians and is associated with a higher complication rate but no increased mortality.

Correlations between elementary sensory tasks and IQ scores have been cited in support of Galtonian theories of intelligence, which emphasize speed of signal encoding and transmission in the nervous system. We argue that a Galtonian view is warranted only when data from elementary tasks are viewed in isolation. Data presented indicate that, when simple and complex tasks are contrasted, simple tasks provide the poorest estimates of intelligence. Theories of intelligence, therefore, must explicitly address the central role of task complexity.