Circulation
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Repeated brief episodes of myocardial ischemia performed by mechanical clamping of a coronary artery "precondition" the heart and reduce infarct size after a subsequent sustained ischemia. It is not known, however, whether spontaneous episodes of transient ischemia caused by formation of platelet thrombi, which may occur in unstable angina, have a similar cardioprotective effect. ⋯ We therefore conclude that repeated coronary thrombus formation preconditions the ischemic myocardium: In fact, in contrast to mechanical preconditioning, cardioprotection provided by CFV persisted following 90 minutes of sustained coronary occlusion. However, preconditioning by thrombotic or mechanical occlusion neither preserved myocardial contractile function during sustained coronary occlusion nor prevented stunning after reperfusion. These data raise the possibility that clinical episodes of unstable angina prior to acute myocardial infarction may precondition the ischemic myocardium.
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Early countershock of ventricular fibrillation has been shown to improve immediate and long-term outcome of cardiac arrest. However, a number of investigations in the laboratory and in the clinical population indicate that immediate countershock of prolonged ventricular fibrillation most commonly is followed by asystole or a nonperfusing spontaneous cardiac rhythm, neither of which rarely respond to current therapy. The use of epinephrine in doses greater than those currently recommended has recently been shown to improve both cerebral and myocardial perfusion during cardiopulmonary resuscitation (CPR). The purpose of this study was to compare cardiac resuscitation outcome between immediate countershock of prolonged ventricular fibrillation with high-dose epinephrine therapy and conventional CPR before countershock of prolonged ventricular fibrillation in a canine model. ⋯ The findings of this study suggest that a brief period of myocardial perfusion before countershock improves cardiac resuscitation outcome from prolonged ventricular fibrillation.
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We studied the joint effect of baseline triglyceride and lipoprotein cholesterol levels on the incidence of cardiac end points in the trial group (n = 4,081) of the Helsinki Heart Study, a 5-year randomized coronary primary prevention trial among dyslipidemic middle-aged men. The relative risks (RR) were calculated using Cox proportional hazards models with a dummy variable technique that allows simultaneous study of subgroup combinations from the placebo and treatment groups. ⋯ Serum triglyceride concentration has prognostic value, both for assessing coronary heart disease risk and in predicting the effect of gemfibrozil treatment, especially when used in combination with HDL-C and LDL-C.
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Percutaneous balloon aortic valvuloplasty has been used as a therapeutic option for relief of valvular stenosis. This study describes patients undergoing initial percutaneous aortic balloon valvuloplasty enrolled in the National Heart, Lung, and Blood Institute (NHLBI) Balloon Valvuloplasty Registry. ⋯ These data reveal that percutaneous aortic balloon valvuloplasty in an elderly and debilitated population can be done with low mortality but substantial morbidity. Mortality is greatest in patients with multiorgan failure resulting from poor cardiac output. In patients with reasonably preserved LV function who are otherwise inappropriate surgical candidates because of comorbid factors, survival and early improvement in symptomatic status are frequently observed after percutaneous aortic valvuloplasty.