The 2020 Canadian Cardiovascular Society/Canadian Heart Rhythm Society Comprehensive guidelines for the management of Atrial Fibrillation

The Canadian Cardiovascular Society (CCS) atrial fibrillation (AF) guidelines program was developed to aid clinicians in the management of these complex patients, as well as to provide direction to policy makers and health care systems regarding related issues. The most recent comprehensive CCS AF guidelines update was published in 2010. Since then, periodic updates were published dealing with rapidly changing areas. However, since 2010 a large number of developments had accumulated in a wide range of areas, motivating the committee to complete a thorough guideline review. The 2020 iteration of the CCS AF guidelines represents a comprehensive renewal that integrates, updates, and replaces the past decade of guidelines, recommendations, and practical tips. It is intended to be used by practicing clinicians across all disciplines who care for patients with AF. The Grading of Recommendations, Assessment, Development and Evaluations (GRADE) system was used to evaluate recommendation strength and the quality of evidence. Areas of focus include: AF classification and definitions, epidemiology, pathophysiology, clinical evaluation, screening and opportunistic AF detection, detection and management of modifiable risk factors, integrated approach to AF management, stroke prevention, arrhythmia management, sex differences, and AF in special populations. Extensive use is made of tables and figures to synthesize important material and present key concepts. This document should be an important aid for knowledge translation and a tool to help improve clinical management of this important and challenging arrhythmia.

Le programme de lignes directrices de la Société canadienne de cardiologie (SCC) en matière de fibrillation auriculaire (FA) a été élaboré pour aider les cliniciens à prendre en charge ces patients complexes, ainsi que pour orienter les décideurs politiques et les systèmes de soins de santé sur des questions connexes. La dernière édition complète des lignes directrices de la SCC en matière de FA a été publiée en 2010. Depuis lors, des mises à jour périodiques ont été publiées, traitant de domaines en évolution rapide. Cependant, en 2020, un grand nombre de développements s'y étaient ajoutés, couvrant un large éventail de domaines, ce qui a motivé le comité à créer une refonte complète des lignes directrices. L'édition 2020 des lignes directrices de la SCC en matière de FA représente un renouvellement complet qui intègre, met à jour et remplace les lignes directrices, les recommandations et les conseils pratiques des dix dernières années. Elle est destinée à être utilisée par les cliniciens praticiens de toutes les disciplines qui s'occupent de patients souffrant de FA. L'approche GRADE (Gradation des Recommandations, de l'Appréciation, du Développement et des Évaluations) a été utilisée pour évaluer la pertinence des recommandations et la qualité des résultats. Les domaines d'intérêt incluent : la classification et les définitions de la FA, son épidémiologie, sa physiopathologie, l'évaluation clinique, le dépistage de la FA, la détection et la gestion des facteurs de risque modifiables, l'approche intégrée de la gestion de la FA, la prévention des accidents vasculaires cérébraux, la gestion de l'arythmie, les différences entre les sexes et la FA dans des populations particulières. Des tableaux et figures ont été largement utilisés pour synthétiser les éléments importants et présenter les concepts clés. Ce document devrait représenter une aide importante pour l'intégration des connaissances et un outil pour aider à améliorer la gestion clinique de cette arythmie importante et difficile à traiter.

Cost-effectiveness of alternative changes to a national blood collection service.

OBJECTIVES: To evaluate the cost-effectiveness of changing opening times, introducing a donor health report and reducing the minimum inter-donation interval for donors attending static centres. BACKGROUND: Evidence is required about the effect of changes to the blood collection service on costs and the frequency of donation. METHODS/MATERIALS: This study estimated the effect of changes to the blood collection service in England on the annual number of whole-blood donations by current donors. We used donors' responses to a stated preference survey, donor registry data on donation frequency and deferral rates from the INTERVAL trial. Costs measured were those anticipated to differ between strategies. We reported the cost per additional unit of blood collected for each strategy versus current practice. Strategies with a cost per additional unit of whole blood less than £30 (an estimate of the current cost of collection) were judged likely to be cost-effective. RESULTS: In static donor centres, extending opening times to evenings and weekends provided an additional unit of whole blood at a cost of £23 and £29, respectively. Introducing a health report cost £130 per additional unit of blood collected. Although the strategy of reducing the minimum inter-donation interval had the lowest cost per additional unit of blood collected (£10), this increased the rate of deferrals due to low haemoglobin (Hb). CONCLUSION: The introduction of a donor health report is unlikely to provide a sufficient increase in donation frequency to justify the additional costs. A more cost-effective change is to extend opening hours for blood collection at static centres.

Randomized Trial of Primary PCI with or without RoutineManual Thrombectomy

During primary percutaneous coronary intervention (PCI), manual thrombectomymay reduce distal embolization and thus improve microvascular perfusion. Smalltrials have suggested that thrombectomy improves surrogate and clinical outcomes,but a larger trial has reported conflicting results.MethodsWe randomly assigned 10,732 patients with ST-segment elevation myocardial infarction(STEMI) undergoing primary PCI to a strategy of routine upfront manualthrombectomy versus PCI alone. The primary outcome was a composite of deathfrom cardiovascular causes, recurrent myocardial infarction, cardiogenic shock, orNew York Heart Association (NYHA) class IV heart failure within 180 days. The keysafety outcome was stroke within 30 days.ResultsThe primary outcome occurred in 347 of 5033 patients (6.9%) in the thrombectomygroup versus 351 of 5030 patients (7.0%) in the PCI-alone group (hazard ratio in thethrombectomy group, 0.99; 95% confidence interval [CI], 0.85 to 1.15; P = 0.86). Therates of cardiovascular death (3.1% with thrombectomy vs. 3.5% with PCI alone;hazard ratio, 0.90; 95% CI, 0.73 to 1.12; P = 0.34) and the primary outcome plusstent thrombosis or target-vessel revascularization (9.9% vs. 9.8%; hazard ratio,1.00; 95% CI, 0.89 to 1.14; P = 0.95) were also similar. Stroke within 30 days occurredin 33 patients (0.7%) in the thrombectomy group versus 16 patients (0.3%)in the PCI-alone group (hazard ratio, 2.06; 95% CI, 1.13 to 3.75; P = 0.02).ConclusionsIn patients with STEMI who were undergoing primary PCI, routine manual thrombectomy,as compared with PCI alone, did not reduce the risk of cardiovasculardeath, recurrent myocardial infarction, cardiogenic shock, or NYHA class IV heartfailure within 180 days but was associated with an increased rate of stroke within30 days. (Funded by Medtronic and the Canadian Institutes of Health Research;TOTAL ClinicalTrials.gov number, NCT01149044.

Cost-effectiveness of magnetic resonance-guided focused ultrasound surgery for treatment of uterine fibroids.

OBJECTIVE: To estimate the cost-effectiveness of a treatment strategy for symptomatic uterine fibroids, which starts with Magnetic Resonance-guided Focused Ultrasound Surgery (MRgFUS) as compared with current practice comprising uterine artery embolisation, myomectomy and hysterectomy. DESIGN: Cost-utility analysis based on a Markov model. SETTING: National Health Service (NHS) Trusts in England and Wales. POPULATION: Women for whom surgical treatment for uterine fibroids is being considered. METHODS: The parameters of the Markov model of the treatment of uterine fibroids are drawn from a series of clinical studies of MRgFUS, and from the clinical effectiveness literature. Health-related quality of life is measured using the 6D. Costs are estimated from the perspective of the NHS. The impact of uncertainty is examined using deterministic and probabilistic sensitivity analysis. MAIN OUTCOME MEASURES: Incremental cost-effectiveness measured by cost per quality-adjusted life-year (QALY) gained. RESULTS: The base-case results imply a cost saving and a small QALY gain per woman as a result of an MRgFUS treatment strategy. The cost per QALY gained is sensitive to cost of MRgFUS relative to other treatments, the age of the woman and the nonperfused volume relative to the total fibroids volume. CONCLUSIONS: A treatment strategy for symptomatic uterine fibroids starting with MRgFUS is likely to be cost-effective.

TELEMAM: a cluster randomised trial to assess the use of telemedicine in multi-disciplinary breast cancer decision making.

AIM: The TELEMAM trial aimed to assess the clinical effectiveness and costs of telemedicine in conducting breast cancer multi-disciplinary meetings (MDTs). METHODS: Over 12 months 473 MDT patient discussions in two district general hospitals (DGHs) were cluster randomised (2:1) to the intervention of telemedicine linkage to breast specialists in a cancer centre or to the control group of 'in-person' meetings. Primary endpoints were clinical effectiveness and costs. Economic analysis was based on a cost-minimisation approach. RESULTS: Levels of agreement of MDT members on a scale from 1 to 5 were high and similar in both the telemedicine and standard meetings for decision sharing (4.04 versus 4.17), consensus (4.06 versus 4.20) and confidence in the decision (4.16 versus 4.07). The threshold at which the telemedicine meetings became cheaper than standard MDTs was approximately 40 meetings per year. CONCLUSION: Telemedicine delivered breast cancer multi-disciplinary meetings have similar clinical effectiveness to standard 'in-person' meetings.

The coxibs and traditional nonsteroidal anti-inflammatory drugs: a current perspective on cardiovascular risks.

There is strong evidence from randomized clinical trials that the highly selective cox-2 inhibitors (coxibs), compared with placebo, cause an excess of serious cardiovascular events that are not mitigated by low-dose acetylsalicylic acid. Both Health Canada and the Food and Drug Administration have concluded that the excess cardiovascular events may be a 'class effect' of all the nonsteroidal anti-inflammatory drugs (NSAIDs), including traditional NSAIDs (tNSAIDs) and coxibs, and now require appropriate black box labelling of all these agents. Celecoxib and lumiracoxib are the only coxibs remaining on the market in Canada. The prostanoid pathways, the roles of cox-1 and cox-2, as well as the inhibitory effects of acetylsalicylic acid, traditional tNSAIDs and the coxibs, are briefly reviewed. Current recommendations for the ongoing use of coxibs and the tNSAIDs are summarized.

Inhibitors of mast cell tryptase beta as therapeutics for the treatment of asthma and inflammatory disorders.

A survey of the available biological data on tryptase inhibitors suggests that there is considerable interest in tryptase as a therapeutic target particularly for the treatment of allergic asthma and inflammatory disorders. This interest was driven primarily by data from studies carried out on the cellular and in vivo actions of this serine protease over the past decade, all of which have suggested a pro-inflammatory role for tryptase. Tryptase beta is the form of interest in allergic asthma and the data from numerous studies have shown that tryptase cannot only contribute to airway bronchoconstriction and hyperresponsiveness, but may have a key role in fibrosis and ECM turnover, hallmarks of the remodeling process. Hence, inhibitors of tryptase have the potential to make an impact on fibrosis and airway wall remodelling. However, few studies, if any, have been carried out to determine the effect of tryptase inhibitors on airway remodeling and this is an area that warrants further investigation with the appropriate models because the eventual positioning of tryptase inhibitors in asthma therapy will be strengthened by data supporting an impact on airway remodeling in addition to effects on bronchial hyperresponsiveness. This review has focused on tryptase inhibitors in the pipeline and it is clear that with a few exceptions, the majority of these compounds are targeted for inhaled delivery. Finally, judging by the interest from numerous pharmaceutical companies, it appears the stage is set for tryptase inhibitors to make their mark as drugs of the future for allergic asthma and the results from clinical trials is awaited with eager anticipation.

Tryptase and agonists of PAR-2 induce the proliferation of human airway smooth muscle cells.

Airway remodeling with smooth muscle cell (SMC) hyperplasia is a feature of chronic asthma. We investigated the potential for tryptase, the major secretory product of human mast cells, to act as a growth factor for human airway SMCs. Because this serine protease can activate proteinase-activated receptor-2 (PAR-2), we also examined the actions of SLIGKV, a peptide agonist of PAR-2. Incubation with lung tryptase provoked a twofold increase in [(3)H]thymidine incorporation; a similar increase in cell numbers was found when we used the MTS assay. The effect was catalytic site dependent, being abolished by the protease inhibitors leupeptin and benzamidine and by heat inactivation of the enzyme. Tryptase-induced DNA synthesis was inhibited by preincubation of the cells with pertussis toxin, calphostin C, or genistein. Transduction mechanisms are thus likely to involve a pertussis toxin-sensitive G protein, protein kinase C, and tyrosine kinase. SLIGKV elicited a response on SMCs similar to that of tryptase. Tryptase could provide an important stimulus for SMC proliferation in asthmatic airways, by acting on PAR-2.

Early asthma prophylaxis, natural history, skeletal development and economy (EASE): a pilot randomised controlled trial.

OBJECTIVES: (1) To establish recruitment rates of newly presenting asthmatic children. (2) To establish acceptability of study protocols. (3) To pilot age-specific quality of life (QoL) assessment. (4) To assess short-term (6 months) outcomes of inhaled corticosteroids (ICS) treatment. (5) To refine sample size calculations for a definitive study. DESIGN: A randomised pragmatic longitudinal trial design was used, with no blinding or placebo, to examine early ICS introduction similar to its use in practice. Subjects were assessed at entry, 3 and 6 months. SETTING: Subjects were recruited from six general practices. Children under 6 years were assessed at the Craig Research and Investigation Unit, Royal Aberdeen Children's Hospital, or their family home, and subjects 6 years and over were assessed at their general practice. SUBJECTS: Children (aged 6 months-16 years) with symptoms suggestive of asthma/wheeze that had commenced no longer than 12 months before were identified retrospectively and prospectively from general practices. Subjects were also required to be naïve to prophylactic therapy with no other lung disease/concomitant illness. INTERVENTIONS: Subjects were randomised to ss2-agonist (ss2-only group) or ss2-agonist and ICS (ICS group) for 6 months. Physicians could later prescribe ICS in controls if needed. MAIN OUTCOME MEASURES: (1) Pulmonary function. (2) Asthma symptom diary. (3) Symptomatic health status questionnaire. (4) Caregiver's and child's QoL. (5) Growth. (6) Bone mass. (7) Bone turnover. (8) Economic issues. RESULTS: Of over 15,000 children yielded from general practice records, 11% had symptoms suggestive of asthma/wheeze, and two-thirds of these already used ICS. Of the remaining, 141 subjects met the criterion of early asthma, and 86 were randomised. Two-thirds of those randomised were < 6 years old, the males:females ratio was 2:1, and 67% had a family history of atopy. RESULTS - PHYSIOLOGICAL DEVELOPMENT: Pulmonary function did not significantly improve in the older children. Although tidal breathing measures in the pre-school children were significantly higher at 6 months in the ss2-only group, there was great variability. Incidence of wheeze and night-time cough reduced equally in both groups. Reduction of night-time symptom score and reliever use, and increase in symptom-free days were only significant in the ss2-only group. No significant differences were found in growth and bone mass between the two groups, but bone metabolism was significantly reduced at 6 months in the ICS group. RESULTS - PSYCHOLOGICAL DEVELOPMENT: The caregiver's QoL questionnaire was sensitive to child symptom changes over 3 months, but absolute impact of child symptoms on their QoL varied, whereas the child-centred questionnaire was not sensitive to change. RESULTS - ECONOMICS: There were no significant differences in medical consultation costs between the groups, but, as expected, prescription costs in the ICS group were higher over 6 months. Combined healthcare costs were significantly higher for patients assigned to ICS, but there were no significant differences in any effectiveness measures between the groups. CONCLUSIONS: Most (96%) of the proposed sample was recruited, and the low drop-out rate (8%) demonstrated acceptability of the study protocol. Most children first presenting with symptoms suggestive of asthma were < 6 years old and represented a group biased towards mild to moderate asthma, or virally induced wheeze. The caregiver's QoL questionnaire was found to better reflect a child's symptom changes than a child-centred instrument. In the short term, no adverse effects were seen on growth, but ICS treatment significantly reduced bone metabolism. Most of the young children with asthma/wheeze improved over time with ss2-agonist treatment alone, and clinical benefits of early ICS intervention amongst these children were not detected; however, there was inadequate power in this pilot study to establish this. (AB

A polymorphic protease-activated receptor 2 (PAR2) displaying reduced sensitivity to trypsin and differential responses to PAR agonists.

Protease-activated receptor 2 (PAR2) is a trypsin-activated member of a family of G-protein-coupled PARs. We have identified a polymorphic form of human PAR2 (PAR(2)F240S) characterized by a phenylalanine to serine mutation at residue 240 within extracellular loop 2, with allelic frequencies of 0.916 (Phe(240)) and 0.084 (Ser(240)) for the wild-type and mutant alleles, respectively. Elevations in intracellular calcium were measured in permanently transfected cell lines expressing the receptors. PAR(2)F240S displayed a significant reduction in sensitivity toward trypsin ( approximately 3.7-fold) and the PAR2-activating peptides, SLIGKV-NH(2) ( approximately 2.5-fold) and SLIGRL-NH(2) ( approximately 2.8-fold), but an increased sensitivity toward the selective PAR2 agonist, trans-cinnamoyl-LIGRLO-NH(2) ( approximately 4-fold). Increased sensitivity was also observed toward the selective PAR-1 agonist, TFLLR-NH(2) ( approximately 7-fold), but not to other PAR-1 agonists tested. Furthermore, we found that TLIGRL-NH(2) and a PAR4-derived peptide, trans-cinnamoyl-YPGKF-NH(2), were selective PAR(2)F240S agonists. By introducing the F240S mutation into rat PAR2, we observed shifts in agonist potencies that mirrored the human PAR(2)F240S, suggesting that Phe(240) is involved in determining agonist specificity of PAR2. Finally, differences in receptor signaling were paralleled in a cell growth assay. We suggest that the distinct pharmacological profile induced by this polymorphism will have important implications for the design of PAR-targeted agonists/antagonists and may contribute to, or be predictive of, an inflammatory disease.

Human mast cell tryptase stimulates the release of an IL-8-dependent neutrophil chemotactic activity from human umbilical vein endothelial cells (HUVEC).

Tryptase, the major product of human mast cell activation, is a potent stimulus of vascular leakage and neutrophil accumulation in vivo in animal studies, but the mechanisms of action remain unclear. Using HUVEC cultures we have sought to investigate the potential of tryptase to alter monolayer permeability or induce the release of neutrophil chemotactic activity. Tryptase (1-100 mU/ml) failed to alter the permeability of endothelial cell monolayers as assessed by albumin flux over 1 h. However, supernatants from endothelial cells treated with tryptase (1-50 mU/ml) for a 24-h period induced neutrophil migration across Transwell filters, with maximal migration observed at 10 mU/ml tryptase. Pretreatment of tryptase with the protease inhibitor leupeptin abolished the chemotactic activity, indicating a dependence on the catalytic site. Moreover, this effect was abolished by addition of an IL-8 neutralizing antibody, suggesting that IL-8 release makes an important contribution to the chemotactic activity. The interaction of mast cell tryptase with endothelial cells could be important in stimulating the ingress of neutrophils following mast cell activation in inflammatory disease.

Negative and zero time preference for health.

The assumption of positive time preference is seldom challenged in analyses of intertemporal choices, despite considerable evidence of zero and negative discount rates. In this study, the majority of respondents have positive discount rates, but a substantial number have negative or zero discount rates. Using probit regression, the perception of the severity of the health-state, gender, education and perception of the questions in terms of difficulty are shown to influence whether individuals have positive discount rates.

Economic analysis of outreach assessment clinics in breast screening programmes.

A model is developed for the economic evaluation of outreach assessment clinics following screening and used to identify the cost-minimizing strategy for assessing women from three island communities in the Scottish Breast Screening Programme (SBSP). There are four options of interest depending on: whether the women are assessed on the mainland or at outreach assessment clinics; and whether all women have two view screening rather than only those being screened for the first time. The benefits of outreach assessment are assumed to be solely in terms of convenience to women and reductions in the time and travel costs of women recalled for assessment. The costs are modelled in order to compare outreach and no outreach options. The results show that for the numbers of women currently screened outreach assessment is the cost-minimizing strategy. The model provides useful guidance with respect to screening policy and is readily applied to the case of outreach assessment in mainland communities outwith major population centres and to breast and other screening programmes in other countries.

Amiodarone interaction with beta-blockers: analysis of the merged EMIAT (European Myocardial Infarct Amiodarone Trial) and CAMIAT (Canadian Amiodarone Myocardial Infarction Trial) databases. The EMIAT and CAMIAT Investigators.

BACKGROUND: Investigations with in vitro and animal models suggest an interaction between amiodarone and beta-blockers. The objective of this work was to explore if an interaction with beta-blocker treatment plays a role in the decrease of cardiac arrhythmic deaths with amiodarone in patients recovered from an acute myocardial infarction. METHODS AND RESULTS: A pooled database from 2 similar randomized clinical trials, the European Amiodarone Myocardial Infarction Trial (EMIAT) and the Canadian Amiodarone Myocardial Infarction Trial (CAMIAT), was used. Four groups of post-myocardial infarction patients were defined: beta-blockers and amiodarone used, beta-blockers used alone, amiodarone used alone, and neither used. All analyses were done on an intention-to-treat basis. Unadjusted and adjusted relative risks for all-cause mortality, cardiac death, arrhythmic cardiac death, nonarrhythmic cardiac death, arrhythmic death, or resuscitated cardiac arrest were lower for patients receiving beta-blockers and amiodarone than for those without beta-blockers, with or without amiodarone. The interaction was statistically significant for cardiac death and arrhythmic death or resuscitated cardiac arrest (P=0.05 and 0.03, respectively). Findings were consistent across subgroups. CONCLUSIONS: These findings are based on a post hoc analysis. However, they confirm prior results from in vitro and animal experiments suggesting an interaction between beta-blockers and amiodarone. In practice, not only is the adjunct of amiodarone to beta-blockers not hazardous, but beta-blocker therapy should be continued if possible in patients in whom amiodarone is indicated.