Circulation
-
Comparative Study
Value of myoglobin, troponin T, and CK-MBmass in ruling out an acute myocardial infarction in the emergency room.
Ruling out acute myocardial infarction (AMI) on the basis of rapid assays for cardiac markers will allow early triage of patients and cost-effective use of available coronary care facilities. ⋯ For ruling out AMI in the emergency room, myoglobin is a better marker than CK-MBmass or troponin T from 3 until 6 hours after the onset of symptoms, but the maximal NPV reaches only 89%. At 7 hours, the NPV of CK-MBmass is 95%. The test characteristics are influenced by the probability of the presence of AMI in the patients studied and by the size of their AMI. Infarct size of AMI patients should be reported in studies evaluating cardiac markers.
-
Contrast agent-enhanced magnetic resonance imaging (MRI) has the potential to visualize myocardial ischemia. To date, however, no agent has been found that has a sustained effect that allows MRI detection for the entire duration of ischemia and reperfusion and thus is useful in conjunction with stress test MRI. In this article, we introduce the gadolinium complex of N3,N6-bis(2'-myrisotyloxyethyl)-1,8-dioxo-triethylene- tetraamine-N,N,N1,N1-tetraacetic acid [Gd(BME-DTTA)], an agent potentially useful for such a purpose. ⋯ This study demonstrates that Gd(BME-DTTA) induces a sustained MRI contrast between regions of normal versus ischemic myocardium, showing the potential of this agent for the diagnosis of ischemic heart disease in conjunction with stress tests.
-
Randomized Controlled Trial Clinical Trial
Evaluation of importance of central effects of atenolol and metoprolol measured by heart rate variability during mental performance tasks, physical exercise, and daily life in stable postinfarct patients.
Physical exercise and mental work cause alterations in cardiac autonomic control. beta-Blockers protect the heart against stress, and this effect may be in part centrally mediated. In this context, the lipophilicity of the drug would be clinically relevant. ⋯ In stable postinfarct patients, chronic treatment with metoprolol and atenolol attenuates the reduction in HR variability induced by mental performance tasks, but the effects during exercise are limited. beta-Blockers do not appear to increase vagal tone in this stable patient group. The point of action in these patients is mainly a reduction in HR, probably due to a reduction in stress-induced sympathetic activation. Clinically significant differences between atenolol and metoprolol were absent, indicating that the degree of lipophilicity does not distinguish among the beta-blockers what their salutary effects are on HR variability during the specific challenges used.
-
Randomized Controlled Trial Multicenter Study Comparative Study Clinical Trial
Dose-ranging study of intravenous amiodarone in patients with life-threatening ventricular tachyarrhythmias. The Intravenous Amiodarone Multicenter Investigators Group.
Oral amiodarone effectively suppresses ventricular arrhythmias; however, full activity may take days or weeks. In patients with frequent, life-threatening ventricular arrhythmias, this delay is not acceptable. Thus, in these patients, the speed and dosing accuracy of an intravenous formulation would be beneficial. The goal of this study was to demonstrate the efficacy of intravenous amiodarone in patients with refractory, recurrent hemodynamically destabilizing ventricular tachycardia or ventricular fibrillation by determining a dose response among three regimens. ⋯ Intravenous amiodarone is effective for the treatment of recurrent, life-threatening ventricular tachyarrhythmias.
-
The aim of the present study was to investigate whether Ca2+ uptake into the sarcoplasmic reticulum (SR) is altered in failing human myocardium resulting from dilated cardiomyopathy. ⋯ These findings provide evidence that in failing human myocardium caused by dilated cardiomyopathy, protein levels of SERCA II and phospholamban are unchanged even though mRNA levels for SERCA II and phospholamban and the SERCA II function are reduced compared with nonfailing myocardium.