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 Multicenter Study Clinical Trial
Pharmacokinetics and pharmacodynamics of intravenous diltiazem in patients with atrial fibrillation or atrial flutter.
Diltiazem, a calcium channel blocker, has been shown to be safe and effective in the treatment of patients in atrial fibrillation and/or atrial flutter. However, there have been no pharmacokinetic/pharmacodynamic studies of diltiazem in these patients. ⋯ First, the pharmacokinetics of diltiazem in patients with atrial fibrillation or atrial flutter is nonlinear with an apparent dose-dependent decrease in systemic clearance with increasing infusion rate. Second, using a sigmoidal Emax model, there is a strong relation between plasma diltiazem concentration and percent heart rate reduction. Third, the plasma concentrations of the principal metabolites desacetyldiltiazem and N-desmethyldiltiazem are low and are not expected to contribute significantly to the pharmacodynamics of intravenous diltiazem in these patients.
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Multicenter Study Comparative Study Clinical Trial
Effect of completeness of revascularization on long-term outcome of patients with three-vessel disease undergoing coronary artery bypass surgery. A report from the Coronary Artery Surgery Study (CASS) Registry.
Complete revascularization after coronary artery bypass surgery is a logical goal and improves symptomatic outcome and survival. However, the impact of complete revascularization in patients with three-vessel coronary disease with varying severities of angina and left ventricular dysfunction has not been clearly defined. ⋯ Complete revascularization (grafts to three or more vessels) in patients with three-vessel coronary disease appears to most benefit those with severe angina and left ventricular dysfunction.
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Multicenter Study Clinical Trial
Efficacy of automatic multimodal device therapy for ventricular tachyarrhythmias as delivered by a new implantable pacing cardioverter-defibrillator. Results of a European multicenter study of 102 implants.
Third-generation implantable cardioverter-defibrillators are devices designed to treat ventricular tachycardia (VT) and ventricular fibrillation (VF) by means of overdrive pacing, cardioversion, or defibrillation. So far, the efficacy of tiered therapy has been documented only in small series. Therefore, a European multicenter clinical evaluation study of a new tachyarrhythmia control device, the Medtronic PCD pacer-cardioverter-defibrillator with epicardial patch-lead configuration, was undertaken. ⋯ The implanted device nearly eliminates sudden arrhythmic death in patients with documented, potentially fatal ventricular tachyarrhythmias. Automatic tiered therapy is highly effective to restore sinus rhythm, provided that an integrated two-zone tachycardia detection algorithm is used, assigning lower tachycardia rates to overdrive pacing and/or cardioversion and higher tachycardia rates to defibrillation. In general, spontaneous VTs can be terminated by automatic overdrive pacing, and painful or disturbing countershock therapies are not required to terminate the majority of spontaneous VT episodes.
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Randomized Controlled Trial Multicenter Study Clinical Trial
Double-blind, dose-response, placebo-controlled multicenter study of nisoldipine. A new second-generation calcium channel blocker in angina pectoris.
Nisoldipine is a potent 1:4 dihydropyridine calcium channel antagonist, and doses of 5 or 10 mg administered either once or twice daily have been claimed to exert antianginal effects. There is, however, little information regarding the dose-response relation and whether the drug exerts any consistent effects throughout the dosing interval. In this placebo-controlled, parallel-design study, the dose-response relation of monotherapy with nisoldipine administered twice daily was studied in patients with stable angina pectoris. ⋯ Monotherapy with 2.5, 5, and 10 mg nisoldipine twice a day was not superior to placebo therapy in treating patients with angina pectoris, and the 10-mg-b.i.d. therapy resulted in a statistically insignificant but clinically important increase in the incidence of serious adverse events.