Anticoagulation strategies in atrial fibrillation

Atrial fibrillation (AF) is a major risk factor for stroke and systemic embolization, particularly in the elderly. Approximately 2.3 million adults in the United States have AF, and it is projected that this number will increase to approximately 5.6 million individuals by the year 2050, with over 50% aged 80 years or older. Vitamin K antagonists are currently the most widely accepted means of stroke prevention in patients with AF; unfortunately, this method of treatment is not a feasible option for many patients for numerous reasons. This article examines and compares the various newer therapeutic agents that have either been approved by the US Food and Drug Administration or are still in various stages of clinical testing, and provides an overview of established antithrombotic therapies. We also discuss the role of anticoagulation in the setting of cardioversion in patients with AF

Class 1C antiarrhythmic drugs in atrial fibrillation and coronary artery disease

Class 1C antiarrhythmic drugs (AAD) are effective first-line agents for atrial fibrillation (AF) treatment. However, these agents commonly are avoided in patients with known coronary artery disease (CAD), due to known increased risk in the post-myocardial infarction population. Whether 1C AADs are safe in patients with CAD but without clinical ischemia or infarct is unknown. Reduced coronary flow capacity (CFC) on positron emission tomography (PET) reliably identifies myocardial regions supplied by vessels with CAD causing flow limitation.To assess whether treatment with 1C AADs increases mortality in patients without known CAD but with CFC indicating significantly reduced coronary blood flow.In this pilot study, we compared patients with AF and LVEF ≥50% who were treated with 1C AADs, to age-matched AF patients without 1C AAD treatment. No patient had clinically evident CAD (i.e., reversible perfusion defect, known ≥70% epicardial lesion, PCI, CABG, or myocardial infarction). All patients had PET-based quantification of stress myocardial blood flow (sMBF) and CFC. Death was assessed by clinical follow-up and SSDI search.78 patients with 1C AAD exposure were matched to 78 controls. Over a mean follow-up of 2.0 years, the groups had similar survival (p=0.54). Among patients with CFC indicating the presence of occult CAD (i.e., reduced CFC involving ≥50% of myocardium), 1C-treated patients had survival similar to (p=0.44) those not treated with 1C agents.In a limited population of AF patients with preserved LV function and PET CFC indicating occult CAD, treatment with 1C AADs appears not to increase mortality. A larger study would be required to confidently assess safety of these drugs in this context. This article is protected by copyright. All rights reserved

Utility of serial measurement of biomarkers of cardiovascular stress and inflammation in systolic dysfunction

Evidence links markers of systemic inflammation and heart failure (HF) with ventricular arrhythmias (VA) and/or death. Biomarker levels, and the risk they indicate, may vary over time. We evaluated the utility of serial laboratory measurements of inflammatory biomarkers and HF, using time-dependent analysis.We prospectively enrolled ambulatory patients with left ventricular ejection fraction (LVEF) ≤35% and a primary-prevention implanted cardioverter-defibrillator (ICD). Levels of established inflammatory biomarkers [C-reactive protein, erythrocyte sedimentation rate (ESR), suppression of tumourigenicity 2 (ST2), tumour necrosis factor alpha (TNF-α)] and brain natriuretic peptide (BNP) were assessed at 3-month intervals for 1 year. We assessed relationships between biomarkers modelled as time-dependent variables, VA, and death. Among 196 patients (66±14 years, LVEF 23±8%), 33 experienced VA, and 18 died. Using only baseline values, BNP predicted VA, and both BNP and ST2 predicted death. Using serial measurements at 3-month intervals, time-varying BNP independently predicted VA, and time-varying ST2 independently predicted death. C-statistic analysis revealed no significant benefit to repeated testing compared with baseline-only measurement. C-reactive protein, ESR, and TNF-α, either at baseline or over time, did not predict either endpoint.In stable ambulatory patients with systolic cardiomyopathy and an ICD, BNP predicts ventricular tachyarrhythmia, and ST2 predicts death. Repeated laboratory measurements over a year's time do not improve risk stratification beyond baseline measurement alone.Clinicaltrials.gov NCT01892462 (https://clinicaltrials.gov/ct2/show/NCT01892462)

Cardiometabolic risk factors and atrial fibrillation

Atrial fibrillation (AF) is the most common arrhythmia worldwide; it is a significant risk factor for stroke and embolization, and has an impact on cardiac function. Despite its impact on morbidity and mortality, our understanding of the etiology and pathophysiology of this disease process is still incomplete. Over the past several decades, there has been evidence to suggest that AF has a significant correlation with metabolic syndrome (MetS). Furthermore, AF appears to be more closely related to specific components of MetS compared with others. This article provides an overview of the various components of MetS and their impact on AF