ISSN:0268-4705    

出版商:OVID    

年代:1999

数据来源: OVID

ISSN:0268-4705    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Homocysteine is a sulfhydryl amino acid formed during metabolism of methionine. Increasing evidence suggests that homocyst(e)ine may act as an independent risk factor for ischemic heart disease, cerebrovascular disease, and peripheral arterial disease. Recent prospective data have shown that homocyst(e)ine levels in the top 20% of the population increase the risk for ischemic heart disease by approximately twofold. Homocyst(e)ine seems to promote the progression of atherosclerosis by causing endothelial dysfunction, increasing oxidant stress, and promoting vascular smooth muscle growth. Recent human studies using methionine loading to experimentally induce moderate hyperhomocyst(e)inemia have demonstrated rapid and profound impairment of resistance and conduit artery endothelial function. No data are available from randomized, controlled trials of the effects of lowering plasma homocyst(e)ine on atherosclerotic vascular events; however, screening for hyperhomocyst(e)inemia should be actively considered in individuals with progressive and unexplained atherosclerosis. Both fasting and postmethionine load homocyst(e)ine levels should be measured. B vitamins, including folic acid and vitamins B6and B12are the mainstay of treatment of patients with hyperhomocyst(e)inemia. Primary prevention strategies await the completion of long-term, randomized, prospective studies.

ISSN:0268-4705    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Coronary heart disease is a highly prevalent and lethal illness for women, particularly in their menopausal years, a fact that fostered interest in hormone use for cardioprotection. Despite the compelling evidence of cardiovascular benefit of estrogen therapy and estrogen and progestin therapy in observational studies of postmenopausal women, and multiple biologically plausible mechanisms for estrogen benefit, precise clinical outcome information from prospective randomized controlled trials is lacking. The only such trial reported, the Heart and Estrogen/Progestin Replacement Study, not only failed to demonstrate cardioprotection, but showed an early adverse outcome in women with documented coronary heart disease who received daily conjugated equine estrogen and medroxyprogesterone acetate. Several large randomized clinical trials of hormone and selective estrogen receptor moderator therapy for primary and secondary prevention are currently underway.

ISSN:0268-4705    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Plasma lipids play a key role in the development of atherosclerosis. Recent trial data support early identification of asymptomatic adults with high-risk lipid profiles for primary prevention of coronary heart disease. 3-Hydroxy-3-methylglutaryl coenzyme A reductase inhibitors have been shown to reduce coronary events in both asymptomatic adults and those with known coronary heart disease. The optimal plasma low-density lipoprotein cholesterol for secondary coronary prevention remains controversial. The Second Report of the Expert Panel on Detection, Evaluation and Treatment of High Blood Cholesterol in Adults (Adult Treatment Panel II), published in 1993 by the National Cholesterol Education Program, recommends guidelines for evaluation and diagnosis of lipids. Subsequently, several clinical trials have identified populations benefiting from pharmacologic intervention and new approaches to the management of lipid disorders. Consequently, these guidelines should be applied with the interval evidence in mind.

ISSN:0268-4705    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Currently 14 million individuals in the United States have coronary disease. Within the next 2 decades, this number is expected to increase to 21 million persons. To minimize the excessive risk of recurrent cardiac events in these people, evidence-based, cost-effective prevention strategies must be developed. This review highlights the evidence supporting commonly used means of secondary prevention and is divided into two major sections: lifestyle modifications and pharmacologic interventions. Lifestyle changes discussed include smoking cessation, especially newer pharmacologic adjuncts; the efficacy of dietary interventions; and current inroads into the treatment of depression in recurrent events. Pharmacologic innovations include reexamination of a role for warfarin; continued advances in the treatment of hyper-and dyslipidemias, new roles for β-blockade in congestive heart failure, and finally a view of future measures, risk, and targets of risk intervention.

ISSN:0268-4705    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Cardiac troponins possess superior sensitivity and specificity for the detection of cardiac injury. They can be used successfully to replace measurements of MB isoenzyme of creatine kinase or lactate dehydrogenase for the retrospective diagnosis of myocardial infarction. Measurement of these proteins confers powerful prognostic information that can be used to triage patients. An increasing body of data suggests that measurement of troponin proteins can be useful to guide therapeutic decisions in patients with acute coronary artery syndromes, especially regarding treatment with low-molecular-weight heparin or IIB/IIIA inhibitors. The absence of troponins in the circulation does not necessarily indicate the absence of coronary artery disease. With current assays, a significant diagnostic difference does not appear to exist between cardiac troponin I and T in patients with acute coronary artery syndromes.

ISSN:0268-4705    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

The inherent limitations of x-ray coronary angiography have led to the development for both noninvasive and minimally invasive techniques for imaging the coronary arteries to assist in the diagnosis and management of patients with ischemic heart disease. Significant advances in transesophageal echocardiography, electron beam computed tomography, and magnetic resonance imaging now permit imaging of the proximal to mid-coronary arteries. Moreover, results of initial studies demonstrate the promise of these methods to detect coronary artery stenoses. In addition, each of these methods provides biochemical or physiologic data about the stenoses that are not obtainable through x-ray angiography. Quantification of coronary calcification via electron beam computed tomography has shown promise as a surrogate marker of coronary atherosclerosis. Transesophageal echocardiography and magnetic resonance imaging appear useful in evaluating the physiologic significance of angiographically detectable coronary artery stenoses via assessment of coronary blood flow. However, it should be noted that significant improvements in technology or acquisition parameters must occur before these techniques can be used on a routine clinical basis for coronary artery imaging. The relative merits and ultimate clinical potential of each of these techniques are discussed in this article.

ISSN:0268-4705    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Each year in the United States, more than 2 million patients are hospitalized with chest pain suggestive of myocardial ischemia, with fewer than 20% of these patients having an acute coronary event. Chest pain emergency units have been created to facilitate urgent therapy for patients with a serious cardiovascular event and to triage lower risk patients to less intensive, more cost-effective inpatient care or discharge to home. The clinical history, physical examination, and initial electrocardiogram are key to initial stratification of patients for further management, but additional methods are necessary to clearly distinguish patients with inconclusive findings at presentation as high-and low-risk. Innovative electrocardiographic methods have increased sensitivity for detecting myocardial ischemia. Accelerated diagnostic protocols with new cardiac serum markers can detect myocardial ischemia or infarction with increasing accuracy. Early echocardiographic, scintigraphic, and treadmill stress protocols can further evaluate patients who have nondiagnostic electrocardiograms and negative serum markers. This review presents the current status of chest pain emergency units and the evolving management strategies they encompass.

ISSN:0268-4705    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Right ventricular (RV) ischemia occurs in 50% of patients with acute inferior myocardial infarction, and may result in severe hemodynamic compromise associated with poor clinical outcome. Right coronary artery occlusion proximal to the RV branches results in RV systolic dysfunction, which decreases transpulmonary delivery of left ventricular (LV) preload and diminishes cardiac output. The ischemic right ventricle is stiff, dilated, and volume dependent, resulting in pandiastolic RV dysfunction. Under these conditions, RV pressure generation and output depend on LV-septal contractile contributions. When the culprit coronary lesion is distal to the right atrial (RA) branches, augmented RA contractility enhances RV performance and optimizes cardiac output. Conversely, more proximal occlusions result in ischemic depression of RA contractility, which impairs RV filling and performance, leading to more severe hemodynamic compromise. Bradyarrhythmias limit the output generated by the rate-dependent noncompliant ventricles. Patients with RV ischemia and hemodynamic compromise often respond to volume resuscitation and restoration of a physiologic rhythm. In some patients, parenteral inotropic stimulation may be required. The ischemic right ventricle appears to be relatively resistant to infarction and has a remarkable ability to recover. The termRV infarctionappears to be a misnomer, as RV performance improves spontaneously even in the absence of reperfusion. Reperfusion, however, enhances the recovery of RV performance and improves the clinical course.

ISSN:0268-4705    

出版商:OVID    

年代:1999

数据来源: OVID