Evolution of spiral and scroll waves of excitation in a mathematical model of ischaemic border zone

Abnormal electrical activity from the boundaries of ischemic cardiac tissue is recognized as one of the major causes in generation of ischemia-reperfusion arrhythmias. Here we present theoretical analysis of the waves of electrical activity that can rise on the boundary of cardiac cell network upon its recovery from ischaemia-like conditions. The main factors included in our analysis are macroscopic gradients of the cell-to-cell coupling and cell excitability and microscopic heterogeneity of individual cells. The interplay between these factors allows one to explain how spirals form, drift together with the moving boundary, get transiently pinned to local inhomogeneities, and finally penetrate into the bulk of the well-coupled tissue where they reach macroscopic scale. The asymptotic theory of the drift of spiral and scroll waves based on response functions provides explanation of the drifts involved in this mechanism, with the exception of effects due to the discreteness of cardiac tissue. In particular, this asymptotic theory allows an extrapolation of 2D events into 3D, which has shown that cells within the border zone can give rise to 3D analogues of spirals, the scroll waves. When and if such scroll waves escape into a better coupled tissue, they are likely to collapse due to the positive filament tension. However, our simulations have shown that such collapse of newly generated scrolls is not inevitable and that under certain conditions filament tension becomes negative, leading to scroll filaments to expand and multiply leading to a fibrillation-like state within small areas of cardiac tissue.Comment: 26 pages, 13 figures, appendix and 2 movies, as accepted to PLoS ONE 2011/08/0

Chronic widespread musculoskeletal pain, fatigue, depression and disordered sleep in chronic post-SARS syndrome; a case-controlled study

<p>Abstract</p> <p>Background</p> <p>The long term adverse effects of Severe Acute Respiratory Syndrome (SARS), a viral disease, are poorly understood.</p> <p>Methods</p> <p>Sleep physiology, somatic and mood symptoms of 22 Toronto subjects, 21 of whom were healthcare workers, (19 females, 3 males, mean age 46.29 yrs.+/- 11.02) who remained unable to return to their former occupation (mean 19.8 months, range: 13 to 36 months following SARS) were compared to 7 healthy female subjects. Because of their clinical similarities to patients with fibromyalgia syndrome (FMS) these post-SARS subjects were similarly compared to 21 drug free female patients, (mean age 42.4 +/- 11.8 yrs.) who fulfilled criteria for fibromyalgia.</p> <p>Results</p> <p>Chronic post-SARS is characterized by persistent fatigue, diffuse myalgia, weakness, depression, and nonrestorative sleep with associated REM-related apneas/hypopneas, an elevated sleep EEG cyclical alternating pattern, and alpha EEG sleep anomaly. Post- SARS patients had symptoms of pre and post-sleep fatigue and post sleep sleepiness that were similar to the symptoms of patients with FMS, and similar to symptoms of patients with chronic fatigue syndrome. Both post-SARS and FMS groups had sleep instability as indicated by the high sleep EEG cyclical alternating pattern rate. The post-SARS group had a lower rating of the alpha EEG sleep anomaly as compared to the FMS patients. The post-SARS group also reported less pre-sleep and post-sleep musculoskeletal pain symptoms.</p> <p>Conclusions</p> <p>The clinical and sleep features of chronic post-SARS form a syndrome of chronic fatigue, pain, weakness, depression and sleep disturbance, which overlaps with the clinical and sleep features of FMS and chronic fatigue syndrome.</p

Reperfusion therapy for ST elevation acute myocardial infarction 2010/2011: current status in 37 ESC countries

Aims Primary percutaneous coronary intervention (PPCI) is the preferred reperfusion therapy in ST-elevation myocardial infarction (STEMI). We conducted this study to evaluate the contemporary status on the use and type of reperfusion therapy in patients admitted with STEMI in the European Society of Cardiology (ESC) member countries. Methods and results A cross-sectional descriptive study based on aggregated country-level data on the use of reperfusion therapy in patients admitted with STEMI during 2010 or 2011. Thirty-seven ESC countries were able to provide data from existing national or regional registries. In countries where no such registries exist, data were based on best expert estimates. Data were collected on the use of STEMI reperfusion treatment and mortality, the numbers of cardiologists, and the availability of PPCI facilities in each country. Our survey provides a brief data summary of the degree of variation in reperfusion therapy across Europe. The number of PPCI procedures varied between countries, ranging from 23 to 884 per million inhabitants. Primary percutaneous coronary intervention and thrombolysis were the dominant reperfusion strategy in 33 and 4 countries, respectively. The mean population served by a single PPCI centre with a 24-h service 7 days a week ranged from 31 300 inhabitants per centre to 6 533 000 inhabitants per centre. Twenty-seven of the total 37 countries participated in a former survey from 2007, and major increases in PPCI utilization were observed in 13 of these countries. Conclusion Large variations in reperfusion treatment are still present across Europe. Countries in Eastern and Southern Europe reported that a substantial number of STEMI patients are not receiving any reperfusion therapy. Implementation of the best reperfusion therapy as recommended in the guidelines should be encourage

Knowledge and Attitudes of Student Pharmacists Regarding Polypharmacy and Deprescribing: A Cross-Sectional Study

Pharmacists play a key role in deprescribing medications. Incorporation of this concept into pharmacy school curricula is important in ensuring that graduates can address the complex needs of an aging population. The aims of this study were to assess if and how student pharmacists were exposed to deprescribing within their curriculum, to assess students&rsquo; perceptions regarding their attitudes, ability and confidence in deprescribing, and to assess if reported curricular exposure to this topic resulted in improved perceptions or objective knowledge assessment scores. An electronic survey was distributed to third- and fourth-year pharmacy students at 132 schools of pharmacy. The survey included three sections including: (i) demographics and questions on their exposure to deprescribing and other experiences within their curriculum; (ii) questions regarding their attitudes, ability, and confidence regarding deprescribing on a 5-point Likert-scale; (iii) a knowledge assessment on polypharmacy and deprescribing in the form of 12 multiple-choice questions. Likert-scale questions were analyzed as scales utilizing the mean score for items measuring student perceptions regarding deprescribing attitudes, ability, and confidence. Comparisons were made on each variable between students with and without curricular exposure to deprescribing using t-tests. Ninety-one responses were included in the analysis. Only 59.3% of respondents reported exposure to deprescribing in their didactic coursework. The mean scores on the polypharmacy and deprescribing knowledge assessments were 61.0% and 64.5%, respectively. Those with exposure to deprescribing concepts within their curriculum were more likely to agree that their school&rsquo;s curriculum prepared them to deprescribe in clinical practice (t(89) = &minus;2.26, p = 0.03). Pharmacy schools should evaluate their curricula and consider the addition of specific deprescribing objectives and outcome measures for didactic and experiential training