Circulation
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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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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.
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Randomized Controlled Trial Comparative Study Clinical Trial
A prospective randomized study of a modified technique of ultrafiltration during pediatric open-heart surgery.
Conventional ultrafiltration (UF) fails to reverse satisfactorily hemodilution and the rise in total body water (TBW) seen after cardiopulmonary bypass (CPB). We have modified the technique, timing, and placement of UF in the CPB circuit and in pilot studies observed controlled elevation of hematocrit and a significantly reduced rise in TBW. We have carried out a prospective randomized study in 50 children undergoing open-heart surgery, comparing modified UF (MUF) with nonfiltered controls. ⋯ Percent rise of systolic blood pressure was 1 (-4 to +9) in controls versus 49 (5-81) in MUF (p = 0.0001); percent rise in diastolic blood pressure 0 (-5 to +8) in controls versus 28 (3-47) in MUF (p = 0.0001). UF reduced the rise in TBW and donor blood requirement associated with CPB in children. The blood pressure rise observed during UF is as yet unexplained, but if proven safe the technique may permit donor blood-free cardiac surgery and prevent the accumulation of potentially dangerous excess tissue fluid.
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Randomized Controlled Trial Comparative Study Clinical Trial
Hemostatic effects of tranexamic acid and desmopressin during cardiac surgery.
Desmopressin-induced release of tissue plasminogen activator from endothelial cells may explain the absence of its hemostatic effect in patients undergoing cardiac surgery. Prior administration of the antifibrinolytic drug tranexamic acid might unmask such an effect, and combination therapy might thereby improve postoperative hemostasis. ⋯ Desmopressin exerts no hemostatic effect, with or without prior administration of antifibrinolytic drug. Prophylactic tranexamic acid alone appears economical and safe in decreasing blood loss and transfusion requirement after cardiac surgery.
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Randomized Controlled Trial Multicenter Study Comparative Study Clinical Trial
Comparative effects of APSAC and rt-PA on infarct size and left ventricular function in acute myocardial infarction. A multicenter randomized study.
Recombinant tissue-type plasminogen activator (rt-PA or alteplase) and anisoylated plasminogen streptokinase activator complex (APSAC or anistreplase) have been demonstrated to limit infarct size significantly and to preserve left ventricular function when injected soon after acute myocardial infarction. However, as yet, the efficacy and safety of these two thrombolytic agents have not been directly compared in one trial; this was the aim of this study. ⋯ The early infusion of APSAC or rt-PA in acute myocardial infarction produced a similar patency rate, limitation of infarct size, and preservation of left ventricular systolic function with an equivalent rate of bleeding complications.