Circulation
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Randomized Controlled Trial Multicenter Study Comparative Study Clinical Trial
A randomized comparison of external and internal cardioversion of chronic atrial fibrillation.
Delivery of shocks within the right atrium has been reported to be more effective than conventional external shocks in converting atrial fibrillation (AF), but these two cardioversion techniques have never been compared prospectively. The purpose of this study was to compare the efficacies of external and internal cardioversion in patients with chronic AF unresponsive to prior attempts at electrical and/or pharmacological cardioversion. Low-dose amiodarone was used in all patients after cardioversion to suppress recurrences of AF. ⋯ Internal cardioversion is more effective than external cardioversion in restoring sinus rhythm and is as safe as external cardioversion in patients with chronic AF. The recurrence rate of AF is the same after both types of cardioversion. If conventional electrical cardioversion is ineffective, internal cardioversion should be attempted. The combination of low-dose amiodarone and external or internal cardioversion may result in maintaining sinus rhythm long-term in patients with refractory AF.
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Randomized Controlled Trial Comparative Study Clinical Trial
Aprotinin prevents cardiopulmonary bypass-induced platelet dysfunction. A scanning electron microscope study.
Administration of aprotinin during extracorporeal circulation reduces blood loss and improves platelet function. ⋯ By preserving platelet function, aprotinin improves postoperative hemostasis in all patients who receive high dose and in most who receive low dose.
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Comparative Study
Precordial QT interval dispersion as a marker of torsade de pointes. Disparate effects of class Ia antiarrhythmic drugs and amiodarone.
Patients with a history of class Ia drug-induced torsade de pointes have been treated with chronic amiodarone without recurrence of torsade de pointes despite comparable prolongation of the QT interval. We hypothesized that in such patients, class Ia drugs cause nonhomogeneous prolongation of cardiac repolarization times, whereas amiodarone causes homogeneous prolongation of cardiac repolarization times. ⋯ An increase in regional QT interval dispersion during class Ia antiarrhythmic drug therapy is associated with torsade de pointes. Chronic amiodarone therapy in patients with a history of class Ia drug-induced torsade de pointes produces comparable maximum QT interval prolongation but does not increase QT interval dispersion. This characteristic may explain its apparent safe use in patients with a history of class Ia drug-induced torsade de pointes.
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beta-Adrenergic receptor blockade has been reported to improve hemodynamics and beta-adrenergic receptor-adenylate cyclase function in idiopathic dilated cardiomyopathy. The purpose of this study was to determine the effects of beta-adrenergic receptor blockade on the beta-adrenergic receptor system and myocardial function in a model of compensated ischemic heart failure. ⋯ After large MI in rats, there is impaired papillary muscle function with decreased beta-adrenergic receptors and adenylate cyclase activity in the noninfarcted myocardium. Propranolol treatment improved basal isometric muscle function and beta-adrenergic receptor density in rats after myocardial infarction but did not improve adenylate cyclase activity or isoproterenol-stimulated muscle function. These data suggest that there is a primary defect in adenylate cyclase function that persists despite upregulation of receptors with propranolol treatment.
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Comparative Study
High-frequency jet ventilation for respiratory failure after congenital heart surgery.
Extracorporeal membrane oxygenation (ECMO) is considered when respiratory failure (RF) persists despite increasing conventional mechanical ventilation (CMV). High-frequency jet ventilation (HFJV) can improve ventilation with comparable mean airway pressure (PAW) to that found on CMV. This study was undertaken to determine whether HFJV is an effective treatment and alternative to ECMO for RF after congenital heart surgery. ⋯ This study suggests that HFJV improves ventilation and is an alternative to ECMO in patients with RF after surgery for congenital heart disease.