Circulation
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Historically, the majority of pulse generators implanted in the United States remain at the nominal programmed settings from the time of implant. While these nominal settings typically allow a sufficient safety margin to prevent later loss of capture with potential chronic threshold rise, the pulse generator with significant use would not be expected to last longer than that predicted by the manufacturer. However, improvements in lead technology have resulted in significantly lower chronic capture thresholds, which would permit lower programmable output settings while still allowing acceptable safety margins. Such changes could result in a significant reduction in long-term battery drain and translate into longer generator life. ⋯ Reprogramming of permanent pacemakers is efficacious and cost-effective.
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In end-stage pulmonary hypertension (PH), the degree of right ventricular (RV) dysfunction has been considered so severe as to require combined heart-lung transplantation. Nevertheless, left ventricular (LV) and RV hemodynamics return to relatively normal levels after single-lung transplantation (SLT) alone. Accordingly, to test the hypothesis that LV and RV systolic function improves after SLT and that the dilated, thick-walled RV reverts to more normal geometry, we used cine MRI and finite-element (FE) analysis to study patients with end-stage PH. ⋯ These results provide evidence supporting the contention that LV and RV systolic function improved after SLT for end-stage PH and that the RV underwent significant remodeling within 3 to 6 months after lung transplantation.
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The perioperative blood coagulation and fibrinolysis system in patients who underwent aortic surgery under deep hypothermic circulatory arrest with or without aprotinin usage was investigated. ⋯ Clinical advantages of hemostatic effects of low-dose aprotinin and no apparent deleterious effects were demonstrated in patients who underwent aortic surgery under deep hypothermic circulatory arrest with retrograde cerebral perfusion. However, blood coagulation and fibrinolytic studies revealed subclinical hypercoagulation. Therefore, and adequate dose of heparin is required during deep hypothermic circulatory arrest.
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The creatine kinase (CK) reaction is important for rapid resynthesis of ATP when the heart increases its work. Studies defining the CK system in human failing and nonfailing myocardium are limited and in conflict. To resolve this conflict, we measured the activities of CK and its isoenzymes and the contents of creatine and CK-B in homogenates of human myocardium. ⋯ In failing and nonfailing donor human myocardium, there is a combined decrease of CK activity and creatine that may impair the ability to deliver ATP to energy-consuming systems.
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Randomized Controlled Trial Multicenter Study Clinical Trial
Efficacy and safety of repeated intravenous doses of ibutilide for rapid conversion of atrial flutter or fibrillation. Ibutilide Repeat Dose Study Investigators.
Currently available antiarrhythmic drugs have limited efficacy for acute termination of atrial fibrillation and flutter, especially if the arrhythmia is not of recent onset. The purpose of this multicenter study was to determine the efficacy and safety of repeated doses of intravenous ibutilide, a class III antiarrhythmic drug, in terminating atrial fibrillation or flutter. ⋯ Intravenous ibutilide given in repeated doses is effective in rapidly terminating atrial fibrillation and flutter and under monitored conditions is an alternative to current cardioversion options.