INSIDE THIS ISSUE OF JACC
Inside This Issue of JACC
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Coronary Artery Disease
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Reduced MIs and Strokes With Intensive Statin Therapy.
While some studies have shown significant benefit to aggressive lipid-lowering with intensive statin therapy, other studies have not. Cannon and colleagues performed a meta-analysis of the 4 large studies that compared intensive with moderate lipid-lowering; TNT, IDEAL, A-to-Z, and PROVE IT–TIMI-22. These trials enrolled over 27,000 patients; intensive therapy subjects had a mean low-density lipoprotein (LDL) of 75 mg/dl versus 101 mg/dl for moderate therapy. This LDL reduction was associated with a significant 16% reduction for coronary death or myocardial infarction (MI), and a 18% reduction in the risk of stroke. Cardiovascular death was reduced by 12% which did not reach statistical significance; total mortality was not affected. This meta-analysis of 4 large but heterogeneous studies suggests that LDL levels of 75 mg/dl are superior to levels of 100 mg/dl for preventing future MIs and strokes, but has limited benefit for reducing total mortality. See page 438. See figure.
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Cardiac Resynchronization Therapy
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Should All CRT Devices Have ICD Capability?.
There has been conflicting evidence on the need for implantable cardioverter-defibrillator (ICD) capability in patients undergoing cardiac resynchronization (biventricular pacing). Ypenburg and colleagues prospectively followed almost 200 patients with advanced heart failure, ejection fraction <35%, and a QRS duration >120 ms who received a combined cardiac resynchronization therapy (CRT)-ICD. Patients were grouped as either primary or secondary prevention based on a history of ventricular arrhythmias. During 1.5 years of follow-up, 21% of primary prevention patients experienced an appropriate ICD therapy, which is high, but significantly lower than the 35% of secondary prevention patients. Both groups had similar clinical improvements and time to first therapy; no significant predictors of the need for ICD therapy were found. This study suggests that all patients who are candidates for CRT should have a device with ICD capability because of the high rate of appropriate ICD discharge in these patients. See page 464. See figure.
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Hypertension
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Genetic Variant in ANP Gene Linked to Ventricular Hypertrophy.
Some individuals develop left ventricular hypertrophy (LVH) disproportionate to their degree of hypertension. Atrial natriuretic peptide (ANP) prevents myocyte hypertrophy in culture, and recent research has identified genetic variation in the sequence for this gene. Rubattu and colleagues performed echocardiograms on 200 people with hypertension and then analyzed their deoxyribonucleic acid for variants of the genes for ANP, brain natriuretic peptide, and the ANP receptor. Approximately 5% of subjects carried a polymorphism of the ANP promoter sequence which was associated with increased left ventricular mass and posterior wall thickness. These subjects also had lower serum levels of ANP providing a physiologic basis for the association. This study demonstrates that a relatively common variant of the ANP gene is responsible for a significant downregulation of ANP gene transcription and is associated with increased cardiac wall thickness in essential hypertension. See pages 499 and 506.
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Autonomic Function
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Norepinephrine Transporter is a Potential Target for Treating Syncope.
The etiology of neurally mediated syncope is poorly understood; the treatment regimens also tend to be unsatisfactory. Schroeder and colleagues hypothesized that norepinephrine transporter inhibitors (NETI) might be effective for neurally mediated syncope by blocking pre-synaptic reuptake of norepinephrine thereby preventing bradycardia and hypotension. Healthy volunteers underwent tilt-table testing either with or without a NETI. The mean tolerated tilt test duration was increased with NETI and subjects were nearly 5 times less likely to terminate the test early. This study helps us to understand the etiology of neurally mediated syncope; preventive therapy with NETI would require balancing the risk of increased heart rate and blood pressure with the symptomatic benefits of less syncope. See page 516. See figure.
Related Article
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Meta-Analysis of Cardiovascular Outcomes Trials Comparing Intensive Versus Moderate Statin Therapy
- Christopher P. Cannon, Benjamin A. Steinberg, Sabina A. Murphy, Jessica L. Mega, and Eugene Braunwald
J. Am. Coll. Cardiol. 2006 48: 438-445.
[Abstract]
[Full Text]
[PDF]
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Coronary Artery Disease
Cardiac Resynchronization...
