INSIDE THIS ISSUE OF JACC
Inside This Issue of JACC
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Viewpoint and Commentary
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Debating the Clinical Significance of Dyssynchrony.
In this issue, two invited viewpoint articles address the clinical utility of various measurements of myocardial dyssynchrony. Kass argues that many of the current techniques used to diagnose dyssynchrony are more a manifestation of the fact that the heart is not a symmetric or simple pump and is subject to a variety of insults, most of which will not benefit from cardiac resynchronization therapy (CRT). Nagueh agrees with some of these points, but argues that when defined appropriately, several measures of dyssynchrony identify patients at risk for worse outcomes, in whom a more aggressive approach, possibly including CRT, seems warranted. Relying solely on QRS prolongation and substantial reductions in ejection fraction to identify patients for CRT seems outdated; however, the clinical utility of imaging-based assessments of dyssynchrony is yet to be solidified. See pages 12 and 18.
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Lipids and Atherosclerosis
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Meta-Analysis Finds Significant Benefits for Statins in the Elderly.
More than 80% of all coronary events occur in patients over the age of 65 years, and it is the leading cause of death in this group. However, only 40% to 60% of post-myocardial infarction (MI) elderly patients are taking statins because of concerns about efficacy and side effects. Afilalo and colleagues pooled data from 9 randomized placebo-controlled trials encompassing almost 20,000 subjects over the age of 65 years. Rates of 5-year all-cause mortality were 16% with statins and 19% with placebo, producing a relative risk reduction of 22% and a number needed to treat of 28. Similar efficacy was found in reducing rates of coronary death, nonfatal MI, and stroke. This meta-analysis shows that statins reduce all-cause mortality in the elderly and that the magnitude of this effect is large. See page 37. See figure.
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Lipids and Atherosclerosis
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Higher HDL Remains Beneficial Even When LDL is <60 mg/dl.
Previous studies have suggested that low high-density lipoprotein cholesterol (HDL-C) increases coronary risk among patients with normal or elevated low-density lipoprotein cholesterol (LDL-C), but less is known about the relationship in patients with low LDL-C. deGoma and colleagues identified over 4,000 subjects with LDL-C levels <60 mg/dl and then developed a primary end point of subsequent myocardial infarction or hospitalization for ischemic heart disease (IHD). The rate of the primary end point showed an inverse relationship with HDL-C, with an odds ratio of 1.6 for those in the lowest quartile (Q) compared with the highest quartile. This relationship persisted regardless of statin use. This study suggests that low HDL-C increases cardiac risk, even in patients with LDL-C below 60 mg/dl. See page 49. See figure.
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Atrial Fibrillation and Cardiac Surgery
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Clues to the Pathogenesis of Post-CABG Atrial Fibrillation.
It has recently been reported that myocardial oxidative injury leads to impaired atrial contraction and a reduction in the atrial effective refractory period, which increases the vulnerability to atrial fibrillation (AF). Kim and colleagues evaluated the role of myocardial nicotinamide adenine dinucleotide phosphate (NADPH) oxidase activity and oxidative stress in the pathogenesis of post-coronary artery bypass graft (CABG) AF by obtaining right atrial tissue samples and blood samples before surgery and again after reperfusion. Patients who developed AF after surgery had significantly increased atrial NADPH oxidase activity. Plasma markers of oxidation did not identify patients who developed AF. High atrial NADPH oxidase activity is associated with an increased risk of post-operative AF, suggesting that this oxidase system may be a key mediator in the pathogenesis of AF after cardiac surgery. See page 68.
Related Articles
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An Epidemic of Dyssynchrony: But What Does It Mean?
- David A. Kass
J. Am. Coll. Cardiol. 2008 51: 12-17.
[Abstract]
[Full Text]
[PDF]
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Mechanical Dyssynchrony in Congestive Heart Failure: Diagnostic and Therapeutic Implications
- Sherif F. Nagueh
J. Am. Coll. Cardiol. 2008 51: 18-22.
[Abstract]
[Full Text]
[PDF]
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Statins for Secondary Prevention in Elderly Patients: A Hierarchical Bayesian Meta-Analysis
- Jonathan Afilalo, Gustavo Duque, Russell Steele, J. Wouter Jukema, Anton J.M. de Craen, and Mark J. Eisenberg
J. Am. Coll. Cardiol. 2008 51: 37-45.
[Abstract]
[Full Text]
[PDF]
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Clinical Significance of High-Density Lipoprotein Cholesterol in Patients With Low Low-Density Lipoprotein Cholesterol
- Emil M. deGoma, Nicholas J. Leeper, and Paul A. Heidenreich
J. Am. Coll. Cardiol. 2008 51: 49-55.
[Abstract]
[Full Text]
[PDF]
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Association of Atrial Nicotinamide Adenine Dinucleotide Phosphate Oxidase Activity With the Development of Atrial Fibrillation After Cardiac Surgery
- Young M. Kim, Hassan Kattach, Chandi Ratnatunga, Ravi Pillai, Keith M. Channon, and Barbara Casadei
J. Am. Coll. Cardiol. 2008 51: 68-74.
[Abstract]
[Full Text]
[PDF]
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Viewpoint and Commentary
Lipids and Atherosclerosis
