The American journal of cardiology
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Randomized Controlled Trial Multicenter Study Clinical Trial
Design of a clinical trial for the assessment of cardioversion using transesophageal echocardiography (The ACUTE Multicenter Study). Steering and Publications Committees of the ACUTE Study.
Patients with atrial fibrillation (AF) undergoing cardioversion are at an increased risk of cardioembolic stroke and require anticoagulation. The Assessment of Cardioversion Using Transesophageal Echocardiography (ACUTE) Multicenter Study is a randomized clinical trial of patients undergoing electrical cardioversion of AF of >2 days' duration comparing a transesophageal-guided strategy (TEE) with brief anticoagulation to the conventional anticoagulation strategy. Patients randomly assigned to the TEE-guided strategy receive therapeutic anticoagulation before TEE and cardioversion, followed by 4 weeks of anticoagulation. ⋯ The anticipated rates of embolism of 2.9% for conventional strategy and 1.2% for the TEE-guided strategy are based on published research and the completed pilot study. The ACUTE Multicenter Study will randomize therapy and follow an estimated 3,000 patients from 65 study sites to determine the relative efficacy of the TEE-guided and conventional approaches to electrical cardioversion for patients in AF. The results of this investigation will have important clinical implications for the management of patients with AF undergoing electrical cardioversion.
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In subjects with a recent acute myocardial infarction, the hour immediately following awakening is associated with an abrupt exaggeration of heart rate-dependent changes and variability of the QT interval. Beta blockers were observed to blunt these waking hour changes.
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Sudden cardiac death due to arrhythmic events is the major cause of mortality among early post-myocardial infarction (MI) patients, accounting for > 250,000 deaths annually in the United States alone. Antiarrhythmic drugs can be used in such patients as well as in those who have not had a recent MI but are at high risk for sudden cardiac death (e.g., those with ventricular tachycardia/fibrillation, or who have survived cardiac arrest). Most antiarrhythmic drugs available, however, have limitations arising from their toxic and proarrhythmic potential. ⋯ Thus, patients with a recent MI and moderately low left ventricular ejection fraction (< or = 36% but not <20%) may be considered for antiarrhythmic therapy. A subset analysis of patients with low heart rate variability can provide valuable additional information. It is important to note that although all-cause mortality is a valid endpoint for such trials, stratification by specific cause of mortality is desirable.
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Randomized Controlled Trial Clinical Trial
Effects of prior aspirin and anti-ischemic therapy on outcome of patients with unstable angina. TIMI 7 Investigators. Thrombin Inhibition in Myocardial Ischemia.
Both aspirin and beta-adrenergic blocking drugs have been shown to reduce the risk of death or acute myocardial infarction (AMI) in patients with unstable angina, but their effect during chronic use on the presentation of acute coronary syndromes is less well defined. Calcium antagonists and oral nitrates are also widely prescribed for patients with coronary disease, but their effect on presentation of acute myocardial ischemia is unknown. We retrospectively examined the effects of prior aspirin and anti-ischemic medical therapy on clinical events in 410 patients hospitalized for unstable angina. ⋯ Prior beta blocker, calcium antagonist, or nitrate administration did not appear to modify presentation as unstable angina or non-Q-wave AMI. In a multivariate model, the combined incidence of death, AMI not present at enrollment, or recurrent angina was best predicted by age (adjusted odds ratio [95% confidence interval] 2.38 [1.14 to 3.98]) and presence of electrocardiographic changes with pain on presentation (adjusted odds ratio 2.83 [1.50 to 5.35]) but was not related to prior or in-hospital medical therapy. Thus, aspirin but not anti-ischemic therapy before hospitalization of patients with unstable angina was associated with a decreased incidence of non-Q-wave AMI on admission.
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Increased QT interval dispersion is associated with ventricular arrhythmias. The aim of this study was to examine if in postmyocardial infarction patients with impaired left ventricular function, increased QT dispersion is associated with ventricular tachycardia (VT) and ventricular fibrillation (VF). Measures of QT dispersion, calculated as maximum-minimum (D) and standard deviation (SD) of QTend, QTapex, JTend, JTapex, and Tend intervals in the 12-lead electrocardiogram, were compared in patients who late after myocardial infarction experienced sustained VT (VT group) only, VF (VF group) only, or had no ventricular arrhythmias (controls). ⋯ VT group had increased QTapexSD, JTapexSD, and JTapexD compared with the VF group. The cycle length of induced sustained monomorphic VT, present in 19 VT and 19 VF patients, correlated with several dispersion indexes in the VT group, but not with those in the VF group. Thus, in postmyocardial infarction patients with a severely damaged left ventricle, increased QT dispersion is associated with susceptibility to sustained VT, but not to VF.