1,721,261 research outputs found
Endothelial dysfunction and pathophysiological correlates in atrial fibrillation
No full textEndothelial dysfunction (ED) increases oxidative stress and proinflammatory agents, and impairs nitric oxide (NO)-dependent vasorelaxation. Atrial fibrillation (AF) is a risk factor for ED as documented by (1) impaired acetylcholine-mediated blood flow increase; (2) reduced plasma nitrite/nitrate levels; (3) additive impairment of flow-mediated dilatation by comorbidities causing ED; and (4) efficacy of cardioversion. Several possible mechanisms sustain the AF-ED association: (1) An impaired rheology. Endothelial NO release is tightly regulated by laminar shear stress and AF induces a turbulent flow which may impair arterial vessel distension and responsiveness. Specifically, Ca2+ elicits NO synthase (eNOS) activation, and shear stress application to endothelial cells increases intracellular Ca2+ primarily in response to regular pulsatile flow at a rate higher than that observed in the presence of oscillatory pulsatile flow. (2) The atrium activity on arterial vessels. The left atrium produces NO and may serve as an endocrine organ releasing nitroso compounds. A disorganised atrial contraction markedly reduces eNOS expression. (3) AF induces atrial inflammation and elevation of C reactive protein and cytokines, exerting a proinflammatory activity on endothelial cells. (4) Systemic factors such as the renin-angiotensin system (RAS) may be prominent. In fact, RAS and inflammation reciprocally "cross-talk". Angiotensin II increases atrial cell death and RAS contributes to myocardial and vascular oxidative stress in AF. RAS inhibition prevents AF. Important clinical correlates of ED in AF patients are muscle underperfusion, premature lactic acidosis and ergoreflex oversignalling during physical activity. This review focuses on the evidence of an association of AF with ED, the possible underlying mechanisms and the pathophysiological correlates
CardioPulse. New clinical cardiopulmonary exercise testing joint statement from the European Society of Cardiology and American Heart Association
No full textThe Impact of Pharmacotherapy on the Cardiopulmonary Exercise Test Response in Patients with Heart Failure : A Mini Review.
No full textCardiopulmonary exercise testing (CPX) is a well-recognized assessment technique in patients with HF. Ventilatory efficiency, aerobic capacity and heart rate recovery are several parameters obtained from CPX that accurately reflect physiologic function and provide robust prognostic information. Pharmacotherapy is a vital component to the management of patients with HF. Numerous pharmacologic interventions, such as ACE inhibition and beta-blockade have demonstrated significant physiologic and prognostic improvement in this population. Furthermore, a number of investigations demonstrating a positive change in the CPX response resulting from a pharmacologic intervention now exist. Because CPX variables reflect pathophysiologic processes differently, their response to a given pharmacologic is unique. For example, beta-blockade has been shown to significantly improve ventilatory efficiency, one of the most powerful prognostic markers obtained from CPX, while not altering aerobic capacity or heart rate recovery. Conversely, ACE and phosphodiesterase-5 inhibition appears to improve ventilatory efficiency and aerobic capacity. Given the prognostic value of CPX, gauging its improvement from pharmacotherapy may be advantageous in facilitating optimal titration of medications. A comprehensive review describing the physiologic and prognostic importance of CPX in the context of pharmacotherapy does not exist. This mini review will: 1. Identify key CPX variables obtained from CPX including aerobic capacity, ventilatory efficiency and heart rate recovery, 2. Describe the physiologic and prognostic significance of CPX in the heart failure population, and, 3. Summarize the present body of evidence addressing the change in CPX in response to different pharmacologic interventions including beta-blockade, renin-angiotensin-aldosterone axis inhibition and sildenafil
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
The future of aerobic exercise testing in clinical practice: is it the ultimate vital sign?
No full textThe four traditional vital signs: resting heart rate, blood pressure, respiratory rate and body temperature, serve as the cornerstone of a physical examination. Other assessments such as pain have been proposed as additional vital signs. To this point however, there has been limited consideration for aerobic exercise assessment as a vital sign. A wealth of literature demonstrating the prognostic, diagnostic and interventional value of the aerobic exercise assessment now exists, supporting its use in numerous clinical scenarios. Moreover, the assessment of the aerobic exercise response allows for the manifestation of physiologic abnormalities that are not readily apparent during the collection of resting data. This review will provide evidence supporting the assertion that the aerobic exercise assessment may be afforded vital sign status in future clinical practice
The clinical and research applications of aerobic capacity and ventilatory efficiency in heart failure : an evidence-based review
No full textA hallmark symptom of heart failure (HF) is exercise intolerance, typically evidenced by excessive shortness of breath, and/or fatigue with exertion. In recent years, the physiologic response to progressive exercise using direct measures of ventilation and gas exchange, commonly termed the cardiopulmonary exercise test (CPX), has evolved into an important clinical tool in the management of patients with HF. There is currently debate regarding the optimal CPX response to apply when stratifying risk for mortality, hospitalization, or other outcomes in patients with HF. Early studies in this area focused on the application of peak VO(2) in predicting outcomes in patients considered for transplantation. More recently, the focus of these studies has shifted to an emphasis on ventilatory inefficiency, in lieu of or in combination with peak VO(2), in estimating risk. The most widely studied index of ventilatory inefficiency has been the minute ventilation/carbon dioxide production (VE/VCO(2)) slope. A growing body of studies over the last decade has demonstrated that among patients with HF, the VE/VCO(2) slope more powerfully predicts mortality, hospitalization, or both, than peak VO(2). A number of investigations have also simultaneously examined the diagnostic importance of peak VO(2) and the VE/VCO(2) slope as well as their respective response to various interventions. This review examines the body of evidence which has used aerobic capacity and ventilatory efficiency as prognostic and diagnostic markers as well as endpoints in interventional trials. Based on this evidence, recommendations for future clinical and research applications of these CPX variables are provided
Prognostic value of cardiopulmonary exercise testing in a group of female patients with heart failure
No full textPrescribing a healthy lifestyle polypill with high therapeutic efficacy in many shapes and sizes
No full textThe paradigm allowing for a lifestyle immersed in unhealthy behaviors to perpetuate to a point where a non-communicable disease (NCD) is eminent or manifests, and then initiating health care interventions, is deeply flawed, results in poor outcomes, and is unsustainable. This paradigm describes the current predominant healthcare model in many countries around the world and has resulted in the continual increase in unhealthy lifestyle patterns that have led to the global NCD epidemic. It is now broadly recognized that rapid integration of a new healthcare model, one heavily focused on primordial and primary NCD prevention, is needed. Being physically active, eating healthy and nutritious foods, not smoking and minimizing second-hand exposure, and maintaining an appropriate body weight are central to this new prevention model. Combined, these four characteristics can be viewed as the key ingredients for the “healthy lifestyle polypill”. Recently, the American Heart Association (AHA), European Society of Cardiology (ESC), European Association for Cardiovascular Prevention and Rehabilitation (EACPR), and American College of Preventive Medicine (ACPM) came together to publish, in both the Mayo Clinic Proceedings and European Heart Journal, a policy statement entitled “Healthy Lifestyle Interventions to Combat Non-Communicable Disease: A Novel Non-Hierarchical Connectivity Model for Key Stakeholders”. We hope the AHA-ESC-EACPR-ACPM healthy lifestyle policy statement prompts a massive increase in production of the healthy lifestyle polypill. Regulatory approval is not needed to start manufacturing and distributing this medication. The polypill can take many forms and have differing ingredients and dosages while still maintaining high therapeutic efficacy
Optimizing the clinical application of cardiopulmonary exercise testing in patients with heart failure
No full textCardiopulmonary exercise testing (CPX) is a well-accepted evaluation technique in patients with heart failure (HF). Even so, interpretation of the wealth of data obtained from CPX remains a challenge. The body of evidence demonstrating the clinical value of CPX in HF point toward several key variables that should be assessed in each patient. These variables include ventilatory efficiency, aerobic capacity, expired carbon dioxide and heart rate recovery. Furthermore, a simple clinical evaluation form, prompting the assessment of key variables, has yet to be developed. The purpose of the present clinical case study in a patient with HF is to highlight key CPX variables and propose a clinical evaluation form
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