Circulation
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Inducible nitric oxide synthase (iNOS) is activated in cardiac disorders. We investigated the contribution of increased iNOS activity to the development of left ventricular dysfunction after myocardial infarction by selective inhibition of the isozyme. ⋯ These findings suggest that induction of iNOS activity 72 hours after infarction exerts negative inotropic effects and contributes to the development of myocardial dysfunction; selective modulation of increased iNOS activity by SMT improves cardiac performance, enhances myocardial blood flow, and may be beneficial in the treatment of acute myocardial infarction.
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Analysis of heart rate variability (HRV) has thus far not been applied in patients with atrial fibrillation, probably because of the presumed absence of any form of patterning of the ventricular rhythm, particularly vagally mediated respiratory arrhythmia. However, such patterning is theoretically conceivable given the function of the atrioventricular node in atrial fibrillation and its susceptibility to autonomic influences. ⋯ This study shows that HRV in patients with atrial fibrillation is related to vagal tone.
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Despite much recent interest in quantification of heart rate variability (HRV), the prognostic value of conventional measures of HRV and of newer indices based on nonlinear dynamics is not universally accepted. ⋯ These results demonstrate that HRV analysis of ambulatory ECG recordings based on fully automated methods can have prognostic value in a population-based study and that nonlinear HRV indices may contribute prognostic value to complement traditional HRV measures.
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Randomized Controlled Trial Clinical Trial
Restenosis after coronary stent placement and randomization to a 4-week combined antiplatelet or anticoagulant therapy: six-month angiographic follow-up of the Intracoronary Stenting and Antithrombotic Regimen (ISAR) Trial.
Platelets and mural thrombus at the lesion site may play a key role in initiating the restenosis process after coronary interventions. The ISAR Trial provides a comparison of the outcomes of patients randomized to two different antithrombotic regimens administered for 4 weeks after successful coronary stent placement: combined antiplatelet therapy (aspirin plus ticlopidine) or a conventional anticoagulant regimen (phenprocoumon with initial overlapping heparin plus aspirin). Within the first 4 weeks after stent placement, combined antiplatelet therapy has been associated with a significant reduction of ischemic complications. In the present study, we examined whether combined antiplatelet therapy administered for 4 weeks after stent placement is able to reduce the process of restenosis at 6 months. ⋯ This study shows that combined antiplatelet therapy (aspirin plus ticlopidine) administered for 4 weeks after coronary Palmaz-Schatz stent placement does not result in a detectable benefit for the prevention of restenosis compared with conventional anticoagulant therapy (phenprocoumon with initial overlapping heparin plus aspirin).
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Endothelium-dependent nitric oxide-mediated vasodilation is impaired in rats with pulmonary hypertension (PH) induced by chronic hypoxia or by monocrotaline injection. We therefore investigated whether the prolonged administration of the nitric oxide precursor L-arginine would alleviate PH in both rat models. ⋯ We conclude that L-arginine ameliorated the changes associated with PH in rats, perhaps by modifying the endogenous nitric oxide production.