Marc A. Pfeffer

Bio: Marc A. Pfeffer is an academic researcher from Brigham and Women's Hospital. The author has contributed to research in topics: Heart failure & Myocardial infarction. The author has an hindex of 166, co-authored 765 publications receiving 133043 citations. Previous affiliations of Marc A. Pfeffer include Partners HealthCare & University of Miami.

Regional cardiac dysfunction and outcome in patients with left ventricular dysfunction, heart failure, or both after myocardial infarction

Abstract: Aims Global measures of left ventricular (LV) function, in particular LV ejection fraction (LVEF) and global myocardial strain measures, are powerful predictors of outcomes in patients with LV dysfunction, heart failure, or both. However, less is known about the relationship between regional myocardial function, especially that assessed by strain echocardiography and clinical prognosis. Methods and results We studied 248 patients with LV dysfunction, heart failure, or both 5 days after first myocardial infarction (MI) from the VALIANT study. We assessed peak longitudinal strain (LS) via B-mode speckle tracking in 12 segments from the apical 4- and 2-chamber views and visually assessed LV wall motion score (WMS). We related these measures of regional myocardial function to each other and to clinical outcomes over 20-month follow-up. Normal reference values for segmental LS were derived from 50 healthy controls. Regional LS (−7.7%, Q1: −11.2%, Q3: −4.9%) was worse in segments with abnormal WMS, although was significantly impaired even in segments scored as normokinetic compared with normal controls (−10.4 ± 5.2% vs. −20.0 ± 7.6%, P < 0.001). In multivariable Cox proportional hazards models, each additional abnormal LS segment was associated with an increased risk of all-cause mortality (hazard ratio: 1.42, 95% confidence interval: 1.06–1.90, P = 0.02) even after adjustment for clinical covariates, including LVEF, LV end-systolic volume, and number of abnormal segments by WMS. Conclusion In patients with LV dysfunction, heart failure, or both after MI, regional LS is significantly depressed even in segments with normal WMS, and this measure was related to adverse outcome.

Renin-Angiotensin System and Cardiac Rupture After Myocardial Infarction

Abstract: Of all the mechanical complications after acute myocardial infarction (MI), cardiac rupture remains the most devastating, dramatic, and deadly. Continued improvements in the care of patients with acute MI have decreased the incidence of cardiac rupture over the past decade to under 3% in patients receiving reperfusion therapy,1 although autopsy evaluation of patients who died suddenly with acute MI has suggested a higher incidence.2,3⇓ Without extremely prompt surgical intervention, patients with cardiac rupture rarely survive. See p 2244 Cardiac rupture in humans generally occurs after transmural MI. Patients who rupture the free wall of the left ventricle typically develop hemopericardium and cardiac tamponade, whereas septal rupture leads to ventricular septal defect. Rupture can occur as early as the first day after infarction, although it most often occurs later in the first week in the setting of myocardial necrosis and neutrophilic infiltration.4 A combination of factors, both pathological and physiological, make the infarct region most vulnerable within the first 7 to 10 days. This is when cardiac tissue in the involving infarct region is weakest and most friable. As ventricular enlargement and infarct thinning commence, regional wall stress can increase precipitously. While prompt reperfusion therapy is thought to lower the incidence of rupture, delayed reperfusion may be associated with an increased risk of rupture.5 Treatment with steroids or nonsteroidal antiinflammatory agents may also be associated with an increased risk of rupture.6,7⇓ While the initial phases of acute infarction are characterized pathologically by neutrophil infiltration and myocyte necrosis, the healing phase of acute MI, beginning after the first week, is typified by mononuclear cell and fibroblast infiltration and the absence of polymorphonuclear leukocytes.4 Resorption of necrotic myocytes often precedes scar formation, which occurs over the ensuing weeks, with accumulation of fibrillar collagen into an …

The Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure: the JNC 7 report.

Abstract: "The Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure" provides a new guideline for hypertension prevention and management. The following are the key messages(1) In persons older than 50 years, systolic blood pressure (BP) of more than 140 mm Hg is a much more important cardiovascular disease (CVD) risk factor than diastolic BP; (2) The risk of CVD, beginning at 115/75 mm Hg, doubles with each increment of 20/10 mm Hg; individuals who are normotensive at 55 years of age have a 90% lifetime risk for developing hypertension; (3) Individuals with a systolic BP of 120 to 139 mm Hg or a diastolic BP of 80 to 89 mm Hg should be considered as prehypertensive and require health-promoting lifestyle modifications to prevent CVD; (4) Thiazide-type diuretics should be used in drug treatment for most patients with uncomplicated hypertension, either alone or combined with drugs from other classes. Certain high-risk conditions are compelling indications for the initial use of other antihypertensive drug classes (angiotensin-converting enzyme inhibitors, angiotensin-receptor blockers, β-blockers, calcium channel blockers); (5) Most patients with hypertension will require 2 or more antihypertensive medications to achieve goal BP (<140/90 mm Hg, or <130/80 mm Hg for patients with diabetes or chronic kidney disease); (6) If BP is more than 20/10 mm Hg above goal BP, consideration should be given to initiating therapy with 2 agents, 1 of which usually should be a thiazide-type diuretic; and (7) The most effective therapy prescribed by the most careful clinician will control hypertension only if patients are motivated. Motivation improves when patients have positive experiences with and trust in the clinician. Empathy builds trust and is a potent motivator. Finally, in presenting these guidelines, the committee recognizes that the responsible physician's judgment remains paramount.

Cochrane Handbook for Systematic Reviews of Interventions

Abstract: The Cochrane Handbook for Systematic Reviews of Interventions is the official document that describes in detail the process of preparing and maintaining Cochrane systematic reviews on the effects of healthcare interventions.

疟原虫var基因转换速率变化导致抗原变异[英]／Paul H, Robert P, Christodoulou Z, et al//Proc Natl Acad Sci U S A

Abstract: 抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1（PfPMP1）与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用，在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员，通过启动转录不同的var基因变异体为抗原变异提供了分子基础。

A New Equation to Estimate Glomerular Filtration Rate

Abstract: The Modification of Diet in Renal Disease (MDRD) Study equation underestimates glomerular filtration rate (GFR) in patients with mild kidney disease. Levey and associates therefore developed and va...

Lifetime Prevalence and Age-of-Onset Distributions of DSM-IV Disorders in the National Comorbidity Survey Replication

Abstract: Context Little is known about lifetime prevalence or age of onset of DSM-IV disorders. Objective To estimate lifetime prevalence and age-of-onset distributions of DSM-IV disorders in the recently completed National Comorbidity Survey Replication. Design and Setting Nationally representative face-to-face household survey conducted between February 2001 and April 2003 using the fully structured World Health Organization World Mental Health Survey version of the Composite International Diagnostic Interview. Participants Nine thousand two hundred eighty-two English-speaking respondents aged 18 years and older. Main Outcome Measures Lifetime DSM-IV anxiety, mood, impulse-control, and substance use disorders. Results Lifetime prevalence estimates are as follows: anxiety disorders, 28.8%; mood disorders, 20.8%; impulse-control disorders, 24.8%; substance use disorders, 14.6%; any disorder, 46.4%. Median age of onset is much earlier for anxiety (11 years) and impulse-control (11 years) disorders than for substance use (20 years) and mood (30 years) disorders. Half of all lifetime cases start by age 14 years and three fourths by age 24 years. Later onsets are mostly of comorbid conditions, with estimated lifetime risk of any disorder at age 75 years (50.8%) only slightly higher than observed lifetime prevalence (46.4%). Lifetime prevalence estimates are higher in recent cohorts than in earlier cohorts and have fairly stable intercohort differences across the life course that vary in substantively plausible ways among sociodemographic subgroups. Conclusions About half of Americans will meet the criteria for a DSM-IV disorder sometime in their life, with first onset usually in childhood or adolescence. Interventions aimed at prevention or early treatment need to focus on youth.