American heart journal
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American heart journal · Feb 2002
Randomized Controlled Trial Multicenter Study Clinical TrialBivalirudin as a replacement for unfractionated heparin in unstable angina/non-ST-elevation myocardial infarction: observations from the TIMI 8 trial. The Thrombolysis in Myocardial Infarction.
The Thrombolysis in Myocardial Infarction (TIMI) 8 trial was undertaken to compare the efficacy and safety of bivalirudin versus unfractionated heparin in a double-blind phase III trial of patients with unstable angina/non-ST-elevation myocardial infarction (MI). ⋯ The trend toward a lower rate of death or nonfatal MI in the bivalirudin group is consistent with a therapeutic effect of the drug and is consistent with other trials of bivalirudin in patients with acute coronary syndromes. The potential for clinically meaningful antithrombotic activity without an increased risk of bleeding and availablility of an alternative anticoagulation strategy in patients who cannot tolerate unfractionated heparin are particularly attractive and underscore the need for further evaluation of bivalirudin.
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American heart journal · Jan 2002
The relative importance of left atrial function versus dimension in predicting atrial fibrillation after coronary artery bypass graft surgery.
Atrial fibrillation (AF) is a common complication after coronary artery bypass graft (CABG) surgery. The purpose of this study was to determine whether pre-existing left atrial dysfunction is a predictor of postoperative AF compared with other clinical predictors. ⋯ Our results demonstrate that age and atrial enlargement, rather than atrial function, were independent predictors of postoperative AF.
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American heart journal · Jan 2002
Influence of left ventricular size and hemodynamics on the systolic longitudinal myocardial Doppler velocity response to stress.
Systolic myocardial Doppler velocity accurately identifies coronary artery disease. However, these velocities may be affected by age, hemodynamic responses to stress, and left ventricular cavity size. We sought to examine the influences of these variables on myocardial velocity during dobutamine stress in patients with normal wall motion. ⋯ Peak systolic velocity during dobutamine stress is relatively independent of hemodynamic factors and left ventricular cavity size. The extremes of age may influence peak systolic Doppler velocities. These results suggest that peak systolic velocity may be a robust quantitative measure during dobutamine echocardiography across most patient subgroups.
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Long QT syndrome (LQT) is characterized by prolongation of the QT interval, causing torsade de pointes and sudden cardiac death. The LQT is a disorder of cardiac repolarization caused by alterations in the transmembrane potassium and sodium currents. Congenital LQT is a disease of transmembrane ion-channel proteins. Six genetic loci of the disease have been identified. Sporadic cases of the disease occur as a result of spontaneous mutations. The acquired causes of LQT include drugs, electrolyte imbalance, marked bradycardia, cocaine, organophosphorus compounds, subarachnoid hemorrhage, myocardial ischemia, protein sparing fasting, autonomic neuropathy, and human immunodeficiency virus disease. ⋯ The diagnosis of LQT primarily rests on clinical and electrocardiographic features and family history. The clinical presentations range from dizziness to syncope and sudden death. Genetic screening is available primarily as a research tool. Short-term treatment of LQT is aimed at preventing the recurrences of torsades and includes intravenous magnesium and potassium administration, temporary cardiac pacing, withdrawal of the offending agent, correction of electrolyte imbalance, and, rarely, intravenous isoproterenol administration. The long-term treatment is aimed at reducing the QT-interval duration and preventing the torsades and sudden death and includes use of oral beta-adrenergic blockers, implantation of permanent pacemaker/cardioverter-defibrillator, and left thoracic sympathectomy. Sodium channel blockers are promising agents under investigation. Electrocardiograms are recorded for screening of family members. The data favor treating asymptomatic patients, if <40 years old at the time of diagnosis, with beta-adrenergic blockers.