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PURPOSE: Hyperreflective foci (HRF) are optical coherence tomography (OCT) biomarkers for progression of non-neovascular age-related macular degeneration (AMD) attributed to anteriorly migrated retinal pigment epithelial (RPE) cells. We examined associations between rod- and cone-mediated vision and HRF plus smaller hyperreflective specks (HRS); we sought a histologic candidate for HRS. DESIGN: cross-sectional study; histologic survey PARTICIPANTS: Patients with normal maculas (n=34), early AMD (N=26), and intermediate AMD (N=41) METHODS: AMD severity was determined via the 9-step Age-Related Eye Disease Study scale. In OCT scans HRF and HRS were manually counted. Vision tests probed cones (best corrected visual acuity (VA), contrast sensitivity), mixed cones and rods (low luminance VA, low luminance deficit, mesopic light sensitivity), or rods (scotopic light sensitivity, rod-mediated dark adaptation (RMDA)). An online AMD histopathology resource was reviewed. MAIN OUTCOME MEASURES: Vision in eyes assessed for HRF and HRS; candidate histology for HRS. RESULTS: In 101 eyes of 101 patients, HRF and HRS were identified in 25 and 95 eyes, respectively, with good intra- and inter-rater reliability. HRF were present but sparse in normal eyes, infrequent in early AMD eyes, and frequent but highly variable among intermediate AMD eyes (number per eye, 0.1±0.2, 0.2±0.5, 1.9 ± 3.4; normal, early, intermediate, respectively). HRS outnumbered HRF in all groups (4.5 ± 3.2; 6.3±5.8; 19.4 ± 22.4). Delayed RMDA was strongly associated with more HRF and HRS (both p

To describe the first known case of Bacteroides spp. related blebitis, keratitis, and endophthalmitis following uncomplicated trabeculectomy.This was a case report and literature review.A 63-year-old immunocompetent white male underwent uncomplicated trabeculectomy of his right eye. Two weeks later, a blebitis with adjacent keratitis was diagnosed, progressing over several days to endophthalmitis despite hourly topical fortified antibiotic therapy. Although gram stain and culture of the bleb surface, a conjunctival suture, the aqueous humor, and the vitreous were negative, topical real-time quantitative polymerase chain reaction testing disclosed the presence of Bacteroides spp. Following treatment with topical and intravitreal clindamycin and intravenous meropenem, all clinical evidence of infection resolved. Best spectacle-corrected visual acuity improved to 20/25 (0.8) subsequent to combined cataract extraction, intraocular lens implantation, and pars plana vitrectomy for persistent vitreous debris.Bacteroides may be a rare cause of postoperative blebitis, keratitis, and endophthalmitis. A favorable outcome may be attained, provided that an accurate diagnosis and effective treatment can be provided, which may be facilitated by real-time quantitative polymerase chain reaction in select cases.

Summary Background Pulmonary arterial hypertension is a chronic disease associated with poor long-term outcomes. Identifying predictors of long-term outcome in pulmonary arterial hypertension is important to assess disease severity and guide treatment. We investigate associations between efficacy parameters and long-term outcomes in patients with pulmonary arterial hypertension receiving riociguat in the PATENT-2 study. We also present safety and efficacy data from the final data cutoff of PATENT-2, where most patients had received at least 2 years of riociguat treatment. Methods Eligible patients from the PATENT-1 study entered the PATENT-2 open-label extension, which will continue until all patients transition to the commercial drug. All patients received riociguat individually adjusted to a maximum dose of 2·5 mg three times a day. The primary endpoint was safety and tolerability, assessed with recording adverse events, serious adverse events, discontinuations, and deaths; exploratory assessments included 6-min walking distance (6MWD), WHO functional class, N-terminal prohormone of brain natriuretic peptide (NT-proBNP)concentrations, Borg dyspnoea score, health-related quality of life (EQ-5D score), survival, and clinical worsening-free survival. Association between efficacy parameters and long-term outcomes was assessed using Kaplan-Meier analyses and a Cox proportional-hazards regression model. PATENT-2 is registered at ClinicalTrials.gov, number NCT00863681. Findings 396 patients entered PATENT-2, of whom 197 patients were receiving riociguat monotherapy and 199 were receiving riociguat in combination with endothelin receptor antagonists or prostanoids, or both. A significant association was noted between 6MWD, NT-proBNP concentration, and WHO functional class and overall survival at baseline (p=0·0006, 0·0225, and 0·0191, respectively), and at follow-up (p=0·021, 0·0056, and 0·0048, respectively). Riociguat was well tolerated in PATENT-2. Serious adverse events were recorded in 238 (60%) of the total population, and 45 (11%) patients discontinued treatment because of an adverse event. Improvements in 6MWD, WHO functional class, and NT-proBNP concentrations were maintained after 2 years of treatment. Interpretation These results support the long-term use of riociguat in patients with pulmonary arterial hypertension, and emphasise the prognostic value of 6MWD, WHO functional class, and NT-proBNP concentrations. Funding Bayer Pharma AG.

The twentieth FIFA World Cup Finals, hosted by Brazil in 2014, provides perspective on the game’s global growth since the inaugural tournament held in Uruguay in 1930. The fifth such tournament sin...

Purpose To summarize the case of a 13 year-old boy diagnosed with a BRAO secondary to B. henselae infection. Observations The patient presented with a sudden, unilateral, and painless scotoma. Fundoscopic findings and multimodal imaging were consistent with a BRAO with associated areas of intraretinal whitening along the involved artery. Upon further questioning, the patient reported having 15 cats at home. Antibodies were positive for B. henselae. The patient was treated with oral doxycycline 100 mg twice daily for 2 months with complete resolution of the retinal findings and the scotoma. Conclusions and importance B. henselae should be considered as a potential cause of retinitis and BRAO, even in pediatric-aged patients.

The study of association football continues its emergence as a vibrant field of inquiry, attracting scholars worldwide from a variety of disciplinary backgrounds. ‘Soccer as the Beautiful Game: Foo...

Hip fracture surgery is associated with a high rate of mortality and morbidity; heart disease is the leading cause and is often unrecognised and inadequately treated. Pre-operative focused transthoracic echocardiography by anaesthetists frequently influences management, but mortality outcome studies have not been performed to date. Mortality over the 12 months after hip fracture surgery, in 64 patients at risk of cardiac disease who received pre-operative echocardiography, was compared with 66 randomised historical controls who did not receive echocardiography. Mortality was lower in the group that received echocardiography over the 30 days (4.7% vs 15.2%, log rank p=0.047) and 12 months after surgery (17.1% vs 33.3%, log rank p=0.031). Hazard of death was also reduced with pre-operative echocardiography over 12 months after adjustment for known risk factors (hazard ratio 0.41, 95% CI 0.2-0.85, p=0.016). Pre-operative echocardiography was not associated with a delay in surgery. These data support a randomised controlled trial to confirm these findings.

This prospective observational study investigated the effect of focused transthoracic echocardiography in 99 patients who had suspected cardiac disease or were ≥ 65 years old, and were scheduled for emergency non-cardiac surgery. The treating anaesthetist completed a diagnosis and management plan before and after transthoracic echocardiography, which was performed by an independent operator. Clinical examination rated cardiac disease present in 75%; the remainder were asymptomatic. The cardiac diagnosis was changed in 67% and the management plan in 44% of patients after echocardiography. Cardiac disease was identified by echocardiography in 64% of patients, which led to a step-up of treatment in 36% (4% delay for cardiology referral, 2% altered surgery, 4% intensive care and 26% intra-operative haemodynamic management changes). Absence of cardiac disease in 36% resulted in a step-down of treatment in 8% (no referral 3%, intensive care 1% or haemodynamic treatment 4%). Pre-operative focused transthoracic echocardiography in patients admitted for emergency surgery and with known cardiac disease or suspected to be at risk of cardiac disease frequently alters diagnosis and management.

David Wingerin (Philadelphia: Temple University Press, 2011). Pp. 264. ISBN: 978-1439906309 The world’s most popular game has struggled for attention in the crowded American sports scene. Millions ...

The aim of this study was to re-evaluate wave reflection in the healthy pulmonary arteries of sheep utilizing the time-domain-based method of wave intensity analysis. A thorough understanding of patterns of wave reflection during health and disease may provide future sensitive markers of early pulmonary vascular disease. Wave intensity was calculated from the simultaneous acquisition of proximal pulmonary arterial pressure and velocity in 12 anesthetized open-chest sheep. Normal pulmonary arterial wave speed was 2.1 ± 0.3 m s(-1). The incident forward compression wave generated by right ventricular systole was reflected in an open-end manner as a backward expansion wave from a site 3 cm downstream, corresponding to the main pulmonary bifurcation, and in a closed-end manner as a backward compression wave from a site 21 cm downstream, corresponding to the pulmonary microcirculation. The proximal open-end reflection site was not present throughout the entire cardiac cycle. Wave reflection was minimal with only 1% of the incident forward compression wave energy reflected as a backward expansion wave and 2% as a backward compression wave. The normal pulmonary artery in open-chest sheep is characterized by variable proximal open-end reflection from the main pulmonary bifurcation and fixed closed-end reflection from the microcirculation, generating backward-travelling waves of minimal intensity.

Pulmonary hypertension is a severe progressive disease with a marked morbidity and a high mortality attributed to right heart failure. Bosentan, a dual endothelin receptor antagonist, is an effective and well-tolerated oral therapy for the management of pulmonary arterial hypertension (PAH; WHO group 1 pulmonary hypertension). Bosentan improves cardiopulmonary hemodynamics, exercise capacity, WHO functional class and quality of life, as well as delaying time to clinical worsening in patients with PAH. This article reviews the role of endothelin-1 in the pathogenesis and progression of PAH, the diagnosis of PAH and the pharmacology of bosentan, and summarizes the current available evidence for the safety and efficacy of bosentan for the treatment of PAH as a monotherapy and combination therapy, as well as its role in the management of other forms of pulmonary hypertension.

The terrace culture of the 1970s and 1980s that spawned the acts of hooliganism chronicled in such groundbreaking football writing as Bill Buford’s Among the Thugs has given way to the rather more ...

A method for determining the bidomain conductivity values is developed. The study was generated because the different sets of measured conductivity values reported in the literature each produce significantly different bidomain simulation results. The method involves mapping the propagation of the electrical activation of cardiac tissue, initiated by point stimulation, via extracellular electrodes. A time-dependent bidomain model is used to simulate the electrical phenomena. The optimum set of conductivity values is achieved by minimizing the difference between the bidomain model output and the measured extracellular potential, by means of inverse techniques in parameter estimation least-squares and singular value decomposition. The method is validated with synthetic data with added random noise. Other parameters in the model such as membrane capacitance and fiber angle can also be estimated. The method takes a different approach to the conventional four-electrode technique, as it does not require the small electrode separation needed to separate the extracellular current from the intracellular.

Background: Acute cardiogenic pulmonary edema (ACPE) is characterized by acute breathlessness and hypoxia and is associated with poor prognosis. Standard pre-hospital management of ACPE includes high-flow oxygen, nitroglycerin and, in severe cases, assisted ventilation. Patients with ACPE can be supported with newer modalities of non-invasive ventilation, specifically continuous positive airway pressure (CPAP). The aim of this study was to determine whether patients with ACPE treated with CPAP plus low-flow oxygen pre-hospitally have a lower mortality rate than those treated conventionally. Methods: This study was a pre-hospital randomised, non-blinded controlled trial conducted July 2009–July 2010. Included were all participants transported by ambulance and admitted to the Royal Hobart Hospital, Tasmania, Australia. The study population was consecutive persons ≥18 years of age with sudden onset of severe respiratory distress, diagnosed as ACPE. Patients were included if they required ventilatory assistance. Patients required a GCS >12 and blood pressure >90 mmHg systolic to safely receive CPAP. The primary outcome was pre- or in-hospital mortality. Results: In total, 50 patients were enrolled with mean age of 79.8 (±11.9) years. There were two deaths (8.3%) in the CPAP arm and nine (34.6%) in the control arm (RR, −0.24; 95% CI, 0.06–1.00; p=0.051) with a number needed to treat of 4. CPAP plus low-flow oxygen was significantly less likely to result in respiratory acidosis (mean difference in pH, −0.11; 95% CI, −0.04–−0.17; p=0.002), with elevated pCO2 (mean difference, −10.0 mmHg; 95% CI, −19.2–−0.78; p=0.026). The length of hospital stay was significantly shorter in the surviving patients who received CPAP (ratio of means, 0.45; 95% CI, 0.29–0.70; p≤0.001). Discussion: This study, which provides interim results due to early termination of the trial, shows CPAP in the pre-hospital setting for ACPE is practicable and is associated with improved patient outcomes.

Pulmonary veno-occlusive disease (PVOD) is a rare cause of pulmonary hypertension characterised by extensive fibrotic occlusion of pulmonary veins. PVOD has a similar insidious presentation to idiopathic pulmonary arterial hypertension but responds poorly to conventional therapies and has a worse prognosis. The current study reports the case of a Caucasian female with a long history of progressive dyspnoea ultimately diagnosed as focal granulomatous venulitis leading to a pulmonary veno-occlusive disease-like pathology. The present study highlights the challenges in diagnosing and treating this condition.

A recently presented solution method for the bidomain model (Johnston et al. 2006), which involves the application of direct current for studying electrical potential in a slab of cardiac tissue, is extended here to allow the use of an applied alternating current. The advantage of using AC current, in a four-electrode method for determining cardiac conductivities, is that instead of using ‘close’ and ‘wide’ electrode spacings to make potential measurements, increasing the frequency of the AC current redirects a fraction of the current from the extracellular space into the intracellular space. The model is based on the work of Le Guyader et al. (2001), but is able to include the effects of the fibre rotation between the epicardium and the endocardium on the potentials. Also, rather than using a full numerical technique, the solution method uses Fourier series and a simple one dimensional finite difference scheme, which has the advantage of allowing the potentials to be calculated only at points, such as th...

This paper presents a mathematical model and new solution technique for studying the electric potential in a slab of cardiac tissue. The model is based on the bidomain representation of cardiac tissue and also allows for the effects of fibre rotation between the epicardium and the endocardium. A detailed solution method, based on Fourier Series and a simple one-dimensional finite difference scheme, for the governing equations for electric potential in the tissue and the blood, is also presented. This method has the advantage that the potential can be calculated only at points where it is required, such as the measuring electrodes. The model is then used to study various electrode configurations which have been proposed to determine cardiac tissue conductivity parameters. Three electrode configurations are analysed in terms of electrode spacing, placement position and the effect of including fibre rotation: the usual surface four-electrode configuration; a single vertical analogue of this and a two probe configuration, which has the current electrodes on one probe and the measuring electrodes on the other, a fixed distance away. It is found that including fibre rotation has no effect on the potentials measured in the first two cases; however, in the two probe case, non-zero fibre rotation causes a significant drop in the voltage measured. This leads to the conclusion that it is necessary to include the effects of fibre rotation in any model which involves the use of multiple plunge electrodes.

This study looks at pulsatile blood flow through four different right coronary arteries, which have been reconstructed from biplane angiograms. A non-Newtonian blood model (the Generalised Power Law), as well as the usual Newtonian model of blood viscosity, is used to study the wall shear stress in each of these arteries over the entire cardiac cycle. The difference between Newtonian and non-Newtonian blood models is also studied over the whole cardiac cycle using the recently generalised global non-Newtonian importance factor. In addition, the flow is studied by considering paths of massless particles introduced into the flow field. The study shows that, when studying the wall shear stress distribution for transient blood flow in arteries, the use of a Newtonian blood model is a reasonably good approximation. However, to study the flow within the artery in greater detail, a non-Newtonian model is more appropriate.

edited by Hallgeir Gammelsaeter and Benoit Senaux, London and New York, Routledge, 2011, 302 pp., £80.00/US$133.00 (hardcover); £28.00/US$44.95 (paperback), ISBN 978-0-415-88378-8 As soccer is among...

Routinely performed biplane digital coronary angiograms were used to construct a three-dimensional model of the coronary arteries. The technique took the images and automatically picked the centreline and radii in each. By reading the information contained in the DICOM format, the rotation angle between the two images could be ascertained, and the centreline in three dimensions could be determined. Once the centreline and radii had been calculated, a finite volume mesh of the artery was constructed that could be used as input into a fluid dynamics package that solves Navier-Stokes equations. A four-section method was adopted for constructing the mesh, utilising three tubular segments and a small junction section. The tubes were constructed automatically, and the junction procedure was semi-automated, maximising user-control over this region. A structured mesh was used for the tubes, and an unstructured mesh was used to model accurately the irregular shape of the junction. The accuracy of the reconstruction method was established by projection of a mesh onto an independent image of the same artery and the use of a coronary phantom. These tests, along with calibration of the edge detection, established an error of less than 2% in the model.

This study looks at blood flow through four different right coronary arteries, which have been reconstructed from bi-plane angiograms. Five non-Newtonian blood models, as well as the usual Newtonian model of blood viscosity, are used to study the wall shear stress in each of these arteries at a particular point in the cardiac cycle. It was found that in the case of steady flow in a given artery, the pattern of wall shear stress is consistent across all models. The magnitude of wall shear stress, however, is influenced by the model used and correlates with graphs of shear stress versus strain for each model. For mid-range velocities of around 0.2 m s(-1) the models are virtually indistinguishable. Local and global non-Newtonian importance factors are introduced, in an attempt to quantify the types of flows where non-Newtonian behaviour is significant. It is concluded that, while the Newtonian model of blood viscosity is a good approximation in regions of mid-range to high shear, it is advisable to use the Generalised Power Law model (which tends to the Newtonian model in those shear ranges in any case) in order to achieve better approximation of wall shear stress at low shear.

The origin of ST depression in ischemia remains poorly understood. The accepted source is of intracellular current flowing between the ischemic and non ischaemic muscle both in systole and diastole such that the AC recorded electrocardiogram shows ST elevation over the ischemic area. The difficulty comes with partial thickness ischemia where the body surface changes do not allow localisation of the ischemic region. In an animal model we have shown that the reason one cannot see the region on the body surface is that the epicardial distribution of ST segment is almost identical for partial thickness ischaemia in the left anterior descending coronary artery, (LAD) and circumflex coronary artery (Cx) territories. Dissection of the reasons for this finding has lead to 3 contributing factors. The first is the role of the right ventricular blood mass, the second the boundary between ischemia and normal and the third the presence of anisotropy and its contribution. In a block of myocardium with anisotropy included we have shown marked differences between the distributions depending on the anisotropy. We have also shown that the published values of conductivity for use in the bidomain model produce unacceptably disparate results.

Psychrotrophs, particularly Pseudomonas spp. are known to be the main determinants of the shelf-life of pasteurized milk and refrigerated raw milk. It is presumed that they mainly cause spoilage through the elaboration of proteinase and lipase enzymes. At the time of this research, under the relevant European Directive, one of the means of determining the quality of pasteurized milk was the pre-incubated count, which involves incubating the milk sample for 5 d at 6°C followed by a plate count. Examination of numerous pre-incubated counts revealed a bimodal rather than a normal distribution indicating that the types of contaminants in pasteurized milk may be as important as their initial concentration. Pseudomonads that gave particularly high (>5×106 cfu/ml) and low (3 cfu/ml) pre-incubated counts were isolated (high and low count isolates respectively). After the organisms had been subjected to a cold shock no consistent trend between the groups of isolates was detected with respect to lag phase duration. However, the high count isolates consistently had a faster exponential growth rate. Unexpectedly, with the exception of one isolate, the low count isolates produced detectable proteinase and lipase earlier. In addition, with one exception, maximal proteinase and lipase production was observed with the low count isolates. These findings indicate that there is no causal relationship between selective growth advantage and ability to produce proteinase and lipase. It also indicates that the spoilage of pasteurized milk is a complex phenomenon and is worthy of further research.

Psychrotrophs isolated at days 1, 3 and 5 from refrigerated raw milk were monitored for growth kinetics using conductance when they had been inoculated during their lag, log and stationary growth phases. The results indicated that there was a more rapid change in the microflora during the initial stages of storage when the lag phases of the 1, 3 and 5 day isolates were analysed. There was also evidence of the ‘suicide response’. In addition, the fact that the stationary phase cells showed the greatest exponential growth rate may be a contributory factor to their selective advantage.

The aim of this study was to investigate the effect of different conductivity values on epicardial surface potential distributions on a slab of cardiac tissue. The study was motivated by the large variation in published bidomain conductivity parameters available in the literature. Simulations presented are based on a previously published bidomain model and solution technique which includes fiber rotation. Three sets of conductivity parameters are considered and an alternative set of nondimensional parameters relating the tissue conductivities to blood conductivity is introduced. These nondimensional parameters are then used to study the relative effect of blood conductivity on the epicardial potential distributions. Each set of conductivity parameters gives rise to a distinct set of epicardial potential distributions, both in terms of morphology and magnitude. Unfortunately, the differences between the potential distributions cannot be explained by simple combinations of the conductivity values or the resulting dimensionless parameters.

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A method was developed for efficient boundary element method solution of potential problems that were large, linear and involved optimization of boundary geometry. The method involved forming an optimization region containing the section of boundary to be optimized, and an invariant region incorporating the remainder of the problem. Solution was by Gaussian elimination. Matrix elements arising from boundary discretization and application of the governing equations were manipulated to permit computations relating to the invariant region to be performed only once. The matrix and vector terms for the invariant region were first calculated, the matrix converted to upper-diagonal form and the values stored. For each boundary configuration within the optimization region, additional matrix elements were computed and appended to the pre-computed matrix. The complete set of equations were subsequently solved by conversion of the appended matrix terms to upper-diagonal form, followed by back-substitution. A practical example involved determining the electric field arising due to different electrodes implanted in the human heart. Computation time was found to be an order of magnitude less for the second and subsequent electrode configurations than for the first. The method may find application in boundary element method optimization problems involving complex or large regions.

The fish discards surveys, conducted by Northern Ireland, Spain and England under the auspices of EC project 95/094, are multistage in design with a structure of hauls within trips within vessels. The data collected by on-board observers from these surveys enabled investigation into the optimal number of hauls, trips and vessels that require sampling to achieve target levels of precision for each gear type and country. Residual maximum likelihood (REML) was used to estimate the variance components between vessels, between trips within vessels and between hauls within trips within vessels, while examining the significance of the fixed effects of area, quarter and their interaction. To meet the REML requirement that the data are normally distributed, the extreme skewness of the data was corrected by a natural log transformation. The estimated lognormal variance components were used within the multistage formulae to estimate the optimal average sampling levels at each stage. The results showed that more resources than were available during the project were required to achieve a coefficient of variation of 20% for the estimation of discard levels for Northern Ireland twin-rig and Spanish pair trawls., SI

To investigate the pharmacological effect of procainamide on transmural ventricular repolarisation in normal heart, the transmural activation-recovery intervals (ARI) and their responses to procainamide (20 mg/min i.v. for 20 min) were studied in 6 open-chest, pentobarbitone-anaesthetised sheep. ARI was measured from the unipolar ECGs acquired with 4 plunge needles inserted into the basal and apical parts of the left ventricular wall. During sinus rhythm (cycle length 500–700 ms), there was no significant difference in the pooled ARI between the epicardium (266.0 ± 30.5 ms), midmyocardium (265.0 ± 28.9 ms) and endocardium (265.7 ± 28.1 ms) (p > 0.05). Procainamide prolonged ARI in all myocardial layers. The pooled ARI prolongation from the epicardium, midmyocardium and endocardium of the 6 animals was 66.8 ± 18.3, 70.3 ± 14.7 and 65.3 ± 15.7 ms (p > 0.05), respectively. In conclusion, sodium channel blocker procainamide results in a similar repolarisation prolongation in the left ventricular epicardium, midmyocardium and endocardium of a healthy heart.

In this paper, a simple mathematical model of a slab of cardiac tissue is presented in an attempt to better understand the relationship between subendocardial ischaemia and the resulting epicardial potential distributions. The cardiac tissue is represented by the bidomain model where tissue anisotropy and fiber rotation have been incorporated with a view to predicting the epicardial surface potential distribution. The source of electric potential in this steady-state problem is the difference between plateau potentials in normal and ischaemic tissue, where it is assumed that ischaemic tissue has a lower plateau potential. Simulations with tissue anisotropy and no fiber rotation are also considered. Simulations are performed for various thicknesses of the transition region between normal and ischaemic tissue and for various sizes of the ischaemic region. The simulated epicardial potential distributions, based on an anisotropic model of the cardiac tissue, show that there are large, potential gradients above the border of the ischaemic region and that there are dips in the potential distribution above the region of ischaemia. It could be concluded from the simulations that it would be possible to predict the region of subendocardial ischaemia from the epicardial potential distribution, a conclusion contrary to observed experimental data. Possible reasons for this discrepancy are discussed. In the interests of mathematical simplicity, isotropic models of the cardiac tissue are also considered, but results from these simulations predict epicardial potential distributions vastly different from experimental observations. A major conclusion from this work is that tissue anisotropy and fiber rotation must be included to obtain meaningful and realistic epicardial potential distributions.

Ficolins constitute a group of lectins involved in innate immunity. L-Ficolin, H-ficolin, and M-ficolin are present in human serum. The human ficolins differ in carbohydrate-binding specificity, but they have in common the ability to recognize the acetyl group. L-Ficolin and H-ficolin are associated with serine proteases termed MASPs (MBL-associated serine proteases) and their truncated proteins, and the complexes (L/H-ficolin-MASP) activate the lectin pathway of complement upon binding to their ligands. Recombinant M-ficolin is also able to form a complex with MASP, resulting in complement activation. L-Ficolin and H-ficolin can be purified as a complex with MASP from serum by utilizing their binding specificities. These ficolin-MASP complexes have an ability to activate C4. Human ficolins are quantified by ELISA using specific antibodies or ligands.

Background and Purpose —There is still controversy about the prognostic value of motor evoked potentials (MEPs) in the assessment of hemiplegia. The aims of this study are to determine the relationship between functional and electrophysiological recovery and thus the value of MEP as a prognostic indicator of clinical outcome in acute ischemic stroke. Methods —Seventeen healthy subjects and 38 stroke patients were included in this study. Functional recovery was assessed with the Modified Canadian Neurological Scale (MCNS), the Barthel Activities of Daily Living Index (BI), and the Rankin scale. Transcranial magnetic stimulation was used to determine the change in central motor conduction time (CMCT). Stroke outcome was assessed at the end of 2 weeks. One-way ANOVA with post hoc comparisons using the Scheffé procedure as well as t tests were used to assess the significance of the results in this study. Results —Unpaired t test showed significantly higher mean scores of the MCNS (2 P =0.001), BI (2 P =0.002), and Rankin scale ( P P P P Conclusions —These data show that there is a close relationship between clinical and electrophysiological improvement and that MEP is a useful prognostic indicator of clinical outcome.

Background and Purpose —Transcranial Doppler ultrasound (TCD) studies have shown that spontaneous recanalization results in a better clinical improvement after the onset of stroke. However, its effect on electrophysiological recovery is still unknown. The aim of this study was to determine the effects of spontaneous recanalization on the change in central motor conduction time (CMCT) in acute ischemic stroke. Methods —Seventeen healthy subjects and 38 consecutive patients with a first acute ischemic stroke involving the middle cerebral artery territory were included. TCD was used to detect spontaneous recanalization. Transcranial magnetic stimulation was used to determine the change in CMCT on days 1 and 14. Improvement of the CMCT at day 14 was indicated if it decreased in comparison with previous data recorded at day 1 or when a nonrecordable motor response at day 1 reappeared at day 14. No CMCT improvement was indicated when there was no recordable motor response at day 1 and day 14 or the CMCT at day 14 worsened, becoming absent or more delayed. The Pearson χ 2 test was used to assess the statistical significance of the results in this study. Results —Spontaneous recanalization was observed in 62% of the patients: 24% before 24 hours and 38% after this period. No recanalization was observed in 14 patients. The CMCT improved in 87% of the patients who had recanalized before 24 hours and 62% in the recanalized after 24 hours group ( P =0.005). In contrast, CMCT improved in only 17% of the patients in the non-recanalized group Conclusions —These data show that spontaneous recanalization results in a better recovery of the central motor pathway leading to a better CMCT improvement in acute ischemic stroke.

A concentric bipolar electrode (CBE) (consisting of a central disc and an outer annulus) has been proposed as an approximate method of measuring the surface Laplacian of the body surface electrical potential distribution. The derivation of the surface Laplacian approximation, in terms of the potential difference measured with the bipolar electrode, contained an unspecified parameter which has been dubbed the 'effective radius' of the concentric bipolar electrode. This paper presents an asymptotic analysis to derive an expression for the effective radius in terms of the physical dimensions of the electrode (the radius of the central disc and inner and outer radii of the annulus). Also studied is the way in which the value of the effective radius affects the behaviour of the relative error in the surface Laplacian measurement at various dipole source locations within a conducting medium.

A technique of fast Fourier transform analysis has been used to derive mean ventricular fibrillation (VF) intervals, and to confirm that these VF intervals predict ventricular refractory periods. Twenty episodes of VF were induced by a rapid ventricular pacing in 12 sheep. VF activations in a 10-second period were simultaneously acquired from 64 epicardial sites with an electrode sock. The VF electrograms were analyzed by a fast Fourier transform analysis. The dominant peak frequency of the VF spectrum in each epicardial site was converted into milliseconds and served as a mean VF interval. The dominant peak frequency of VF electrograms ranged from 8.1 to 11.5 Hz, and the corresponding mean VF intervals were 87 to 124 ms. In five sheep, the mean VF intervals and the effective refractory periods were determined by the extrastimulus technique obtained from 29 epicardial sites. There was a very good correlation between the two parameters when the effective refractory periods were determined at a basic cycle length of 300 ms (r = 0.89, P0.001) and 400 ms (r = 0.87, P0.001), respectively. VF was induced twice in eight sheep. The maximum difference in the mean VF intervals between the two VF episodes in the same sheep was 3 ms (P0.05). In conclusion, mean VF intervals determined by the fast Fourier transform analysis have a good reproducibility and a good correlation with ventricular refractory periods measured by the classic extrastimulus technique. The mean VF intervals could serve as an index of ventricular refractoriness.

Abstract —To clarify the source of electrocardiographic ST depression associated with ischemia, a sheep model of subendocardial ischemia was developed in which simultaneous epicardial and endocardial ST potentials were mapped, and a computer model using the bidomain technique was developed to explain the results. To produce ischemia in different territories of the myocardium in the same animal, the left anterior descending coronary artery and left circumflex coronary artery were partially constricted in sequence. Results from 36 sheep and the computer simulation are reported. The distributions of epicardial potentials from either ischemic source were very similar ( r =0.77±0.14, P

Background Therapeutic hypothermia (TH) is used to mitigate cerebral injury after an out of hospital cardiac arrest. There is a perceived risk of increased arrhythmias with temperatures lower than the current target of 32–34 °C for TH. This study sought to develop and investigate the electrophysiological changes in a sheep model of systemic hypothermia regarding the susceptibility to ventricular arrhythmias. Methods Ten sheep underwent systemic hypothermia using a venous–venous extra-corporeal circuit whilst instrumented with a 12 lead ECG. An epicardial sock recorded potentials to 30 °C (N = 10) or 26 °C (N = 6). Activation times (AT) and Activation Recovery Intervals (ARI) were calculated using custom software. Results The AT and ARI were significantly prolonged with increased heterogeneity during hypothermia. This effect was most pronounced between normothermia and 34 °C during sinus rhythm (SR). For ventricular pacing (VP) however heterogeneity continued to increase with progressive hypothermia. Conclusions Hypothermia causes a significant increase in the heterogeneity of depolarisation and repolarisation. There is evidence to suggest that SR is protective with most of the increase in heterogeneity occurring with cooling to 34 °C. This raises the possibility that the current target temperatures for therapeutic hypothermia may be safely lowered to provide a gain in cerebral protection.

A rare cause of ST-segment elevation mimicking myocardial infarction has been reported in the setting of acute pneumothorax. We present a middle-aged woman with a right-sided secondary pneumothorax who developed severe chest pain associated with ST-segment elevation suggestive of acute myocardial infarction. Symptoms resolved immediately after advancement of the dislodged chest drain. A subsequent coronary angiogram was normal. This case highlights an uncommon electrocardiographic alteration and discusses possible pathophysiological mechanisms.

To determine the efficacy of body surface potential mapping to detect and quantify reperfusion in acute infarction, 66 patients were studied by repeated body surface potential mapping before and after administration of the thrombolytic agent. The QRS and ST-segment were analyzed and compared to the arterial patency as assessed by arteriography within 10 days. The infarct-related vessel was patent in 50 patients and occluded in the remaining 16. In 6 of the 15 patients in whom thrombolytic therapy was started within 2 hours of the onset of chest pain the ST-segment changed from that of an acute infarction pattern to that of a normal pattern, and the QRS pattern either remained normal or recovered prior to discharge. In two additional patients the ORS pattern returned to normal prior to discharge from the hospital. In the 51 patients with later thrombolytic therapy (≥2 hours) the degree of ST elevation and depression decreased more than either the control infarction group (36 inferior and 73 anterior patients) or the group in whom reperfusion attempts were unsuccessful, but the pattern of the map remained that of an infarction. The QRS maps showed that in the first 48 hours recovery of potential was insufficient to distinguish those with successful thrombolysis. Early reperfusion could be detected by body surface potential mapping and the eventual damage predicted from the degree of change in the QRS map. Later reperfusion could be surmised but not quantified.