USPSTF: Unclear If Benefits of Screening for Atrial Fibrillation Outweigh Harms

MedicalResearch.com Interview with:

Seth Landefeld, M.D.  Dr. Landefeld is chairman of the department of medicine and the Spencer chair in medical science leadership at the University of Alabama at Birmingham (UAB) School of Medicine. Dr. Landefeld also serves on the board of directors of the American Board of Internal Medicine, the UAB Health System, and the University of Alabama Health Services Foundation

Dr. Landefeld

Seth Landefeld, M.D. 
Dr. Landefeld is chairman of the department of medicine and the Spencer chair in medical science leadership at the University of Alabama at Birmingham (UAB) School of Medicine.
Dr. Landefeld also serves on the board of directors of the American Board of Internal Medicine, the UAB Health System, and the University of Alabama Health Services Foundation.

MedicalResearch.com: What is the background for this study? Would you briefly explain what is meant by atrial fibrillation and whom it primarily affects?

Response: Atrial fibrillation—or AF—is an irregular heartbeat. AF affects nearly 3 million Americans and is a leading cause of stroke. Older age and obesity increase the risk of AF, and the condition also occurs more in men than in women. With an aging society and the growing prevalence of obesity in the U.S., this was an important topic for the U.S. Preventive Services Task Force to review.

The Task Force looked at the latest research to see if screening for atrial fibrillation using electrocardiography—or ECG, which is a test that records the activity of someone’s heart—to supplement traditional care is an effective way to diagnose AF and prevent stroke.

We found that more research is needed to determine if screening with ECG can help to identify AF and prevent stroke in adults who are 65 and older and do not have signs or symptoms of the disease.  Continue reading

New Biomarkers Predictive of Atrial Fibrillation Outcome

MedicalResearch.com Interview with:

John D Horowitz, MBBS, PhD. Director of Cardiology/Clinical Pharmacology Queen Elizabeth Hospital University of Adelaide Australia

Dr. Horowitz

John D Horowitz, MBBS, PhD.
Director of Cardiology/Clinical Pharmacology
Queen Elizabeth Hospital
University of Adelaide
Australia 

MedicalResearch.com: What is the background for this study? What are the main findings?

Response:  Atrial fibrillation (AF) describes intermittent or permanent episodes of irregular pulse, due to rapid electrical activity within the atria (filling chambers) of the heart. During AF, the atria quiver, rather than contract, and the response of the ventricles is often rapid, resulting in palpitations and an increased risk of development of heart failure. AF may occur at any age, but is most common in ageing patients (typically over 75 years). The primary importance of AF is that it markedly increases the risk of thrombus formation in the atrium, with the resultant problem that these thrombi may dislodge (embolise), and commonly block arteries in the brain, causing strokes. Hence patients with AF are usually treated with anticoagulants.

Although AF often occurs in patients with prior damage to their hearts and atrial distension, there has been evidence for about the past 8 years that AF also is caused, at least in part, by inflammatory changes: two components have been identified as possible causes for this inflammation: lack of nitric oxide (NO) effect[ NO is  an anti-inflammatory chemical formed by all tissues in the body],  and excess activity of the pro-inflammatory enzyme myeloperoxidase (MPO).  High concentrations of ADMA, which inhibits NO formation, may result from effects of MPO on tissues. SDMA, which is closely related to ADMA, also exerts pro-inflammatory effects and tends to suppress NO formation.

The currently reported study began with the design of the ARISTOTLE trial, an investigation of the (then) novel anticoagulant apixaban as an alternative to warfarin therapy, as a means of preventing strokes in patients with AF. It was elected to perform a substudy to investigate the potential role of ADMA and SDMA as modulators of risk in patients with atrial fibrillation.

This substudy, performed in just over 5000 patients from the ARISTOTLE trial, essentially asked two questions:

(1) There are several indices of stroke risk in patients with atrial fibrillation, such as the CHADS2 score. These all rely on patient characteristics (eg age, presence of diabetes) rather than chemical changes. We postulated that there would be a direct relationship between clinically based risk scores and ADMA/SDMA concentrations.

(2) More ambitiously, we postulated that ADMA and SDMA concentrations would represent INDEPENDENT risk markers for major adverse effects in atrial fibrillation patients on anticoagulant treatment, namely stroke, major bleeding and risk of mortality. 

ADMA/SDMA concentrations were determined in Adelaide, Australia, while statistical analyses were performed in Uppsala, Sweden.

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Variable Effects of Vitamin C on Post-Operative Atrial Fibrillation

MedicalResearch.com Interview with:

Dr-Harri-Hemilae.jpg

Dr. Harri Hemilae

Harri Hemilä, MD, PhD
Department of Public Health
University of Helsinki

MedicalResearch.com: What is the background for this study?

Response: I have a long term interest in vitamin C. Previously I have shown that it alleviates exercise-induced bronchoconstriction (EIB) (http://dx.doi.org/10.1186/1710-1492-10-58 ) and shortens the duration of colds ( http://dx.doi.org/10.1371/journal.pmed.0020168 ). Now I had been following the literature and I noted that a number of randomized trials were being published about vitamin C for preventing post-operative atrial fibrillation (POAF). Therefore I reasoned that it is worthwhile to analyze that set of trials

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Simple Facial Webcam Can Detect Atrial Fibrillation

Jean-Philippe Couderc, PhD, MBA Associate Professor of Medicine Research Associate professor of Electrical and Computer Engineering University of Rochester, NY Heart Research Follow-Up Program - Cardiology Department Rochester, New-York 14642MedicalResearch.com: Interview with:
Jean-Philippe Couderc, PhD, MBA
Associate Professor of Medicine
Research Associate professor of Electrical and Computer Engineering
University of Rochester, NY
Heart Research Follow-Up Program – Cardiology Department
Rochester, New-York 14642

Medical Research: What are the main findings of the study?

Dr. Couderc: We have developed a unique technology which enables any individual to evaluate if he/she suffers from atrial fibrillation (AF) by using a simple video camera (webcam). There are approximately 3.2 million people with AF in the US, and estimated 30 million people in the world. It has been shown that around 30% of people suffering from AF are not aware of their disease, this form is called ‘silent’ atrial fibrillation.  AF is a progressive disease leading to stroke and heart failure.  It results in significant morbidity and mortality. The total cost of AF in the US is estimated to $7billion and 75% of this cost is associated with patient hospitalization.

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Dramatic Increase In Hospitalizations For Atrial Fibrillation As Population Ages

MedicalResearch.com Interview with:
Nileshkumar J. Patel MD
Staten Island University Hospital
Staten Island, NY, 10304 and
Abhishek J. Deshmukh MD
University of Arkansas
Little Rock, AR

MedicalResearch: What are the main findings of the study?

Answer: We analyzed data from almost 4 million hospitalizations for atrial fibrillation (AF) from more than 1,200 hospitals across 45 states in last decade, and found that

–   Hospitalization rates for atrial fibrillation have increased exponentially among US adults during the past 10 years, particularly in those 65 years or older.

–   The most frequent coexisting conditions were hypertension (59.99%), diabetes (21.47%) and chronic pulmonary disease (20.01%).

–   In terms of geographic distribution of admissions, the hospitals in the South constitute (38.5%) the highest percentage of atrial fibrillation hospitalizations, followed by Midwest (24.9%), Northeast (22.2%) and West (14.4%).

–   Overall in-hospital mortality was 1%. The mortality rate was highest in >80 years age group (1.93%) and patients with concomitant heart failure (8.2%).

–   The percentage of patients discharged to nursing facility increased from 8.1% in 2000 to 11.5% in 2010 and need for home health care increased from 6.7% to 13.1%. Approximately one fourth of the patients (25.83%) were discharged to long-term care institution if atrial fibrillation hospitalization was complicated by acute ischemic stroke.

–   Mean cost of AF hospitalization increased significantly from $6,410 in 2001 to $8,439 in 2010 (24.04% increase, p <0.001) even after adjusting for inflation. This represents an absolute increment in annual national cost from approximate 2.15 billion dollars in 2001 to 3.46 billion dollars in 2010. The mean cost of care was highest if AF hospitalization was associated with heart failure ($33,161) and valvular disorders ($28,030).

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