Circulation
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Acute right ventricular (RV) hypertension may result in hemodynamic collapse. The associated reduction in left ventricular (LV) end-diastolic volume is thought to result from reduced RV output (secondary to RV ischemia) and adverse direct ventricular interaction. Aortic constriction improves cardiac function in these circumstances; this has been attributed to a reversal of the RV ischemia caused by an increased coronary perfusion pressure. We hypothesized that altered ventricular interaction, potentially via altered septal mechanics, may also contribute to the beneficial effects of aortic constriction. ⋯ In this model of acute RV hypertension, aortic constriction improves cardiac function, at least in part, by altering ventricular interaction independent of changes in RCA flow. Changes in RCA flow do not appear to have a significant impact on cardiac function in this model in which coronary artery pressure was maintained at normal or increased levels.
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Although autonomic imbalance is known to be characteristics of patients with clinically overt symptomatic congestive heart failure, it is currently unknown whether this autonomic response arises early in the course of left ventricular dysfunction or is restricted to the later stages of circulatory failure. ⋯ The results indicate that autonomic imbalance as reflected in an abnormal pattern of heart rate variability evolves early in the course of ventricular systolic dysfunction consisting of both a significant increase in sympathetically influenced low-frequency heart rate variability and a significant reduction of parasympathetically mediated high-frequency variability. The early appearance of these autonomic abnormalities suggests that autonomic imbalance plays a significant role in promoting the progression of circulatory failure.
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Although family history can be an important risk factor for cardiovascular disease, relatively little is known about the nature of specific genetic risk factors. One approach to this problem is to identify and characterize genes responsible for inherited disorders in the hope that this information will also provide mechanistic insight into common forms of cardiovascular disease. ⋯ Molecular genetic analyses of long-QT syndrome, supravalvular aortic stenosis, and Williams syndrome have begun to unravel the mechanisms underlying these inherited disorders. Rapid genetic testing for Williams syndrome is now available using a simple cytogenetic test, fluorescence in situ hybridization, but additional work will be required for long-QT syndrome and autosomal-dominant supravalvular aortic stenosis. Improved diagnosis and mechanistic understanding of these disorders should lead to rational treatment and prevention.
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Practice Guideline Guideline
Preventing heart attack and death in patients with coronary disease.
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Randomized Controlled Trial Multicenter Study Clinical Trial
Bleeding complications with the chimeric antibody to platelet glycoprotein IIb/IIIa integrin in patients undergoing percutaneous coronary intervention. EPIC Investigators.
The potential for novel antiplatelet and antithrombin agents to contribute to periprocedural bleeding complications of percutaneous coronary revascularization is poorly defined. In the Evaluation of c7E3 Fab in Preventing Ischemic Complications of High-Risk Angioplasty (EPIC) trial, the periprocedural use of aspirin, heparin, and a chimeric antibody to the platelet glycoprotein IIb/IIIa integrin c7E3 Fab in 2099 patients significantly reduced postprocedural ischemic complications and 6-month clinical restenosis but was associated with increased procedural bleeding complications. We review these complications and describe clinical and procedural variables associated with increased bleeding complications in the EPIC trial. ⋯ Bleeding complications unrelated to bypass surgery were two to three times more frequent in patients receiving c7E3 Fab than in those receiving placebo, but most were transient and well tolerated. Risk-factor analysis and modification of concomitant antithrombotic and antiplatelet treatment strategies may aid in reducing bleeding complications and enhancing clinical benefit in patients receiving c7E3 Fab during percutaneous coronary revascularization.