Cardiac electrophysiology review
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Card Electrophysiol Rev · Dec 2003
Randomized Controlled Trial Multicenter Study Clinical TrialDo anticoagulation management services improve care? Implications of the Managing Anticoagulation Services Trial.
An Anticoagulation Clinic Service (ACS) has been proposed as one strategy for improving warfarin treatment for patients with atrial fibrillation. In the Managing Anticoagulation Services Trial (MAST), ACSs meeting specifications for high quality care were established in six managed care organizations (MCOs) which had the patients and resources to support this initiative. The trial followed 1165 patients age >or=65 years who had atrial fibrillation as the primary reason for anticoagulation and were enrolled in a participating MCO. ⋯ In both practice clusters, patients had subtherapeutic INR values (1.5 to 1.99) about one fourth of the time. Providing an ACS in a managed care setting did not appear to improve anticoagulation care over the usual care provided at the sites in this trial but could be a reasonable consideration in a practice setting where time in target range is less than 50%. A higher rate of utilization and a more aggressive stance toward subtherapeutic INR values could potentially enhance the effectiveness of an ACS.
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Card Electrophysiol Rev · Dec 2003
Randomized Controlled Trial Clinical TrialThe Dual Chamber and VVI Implantable Defibrillator (DAVID) Trial: rationale, design, results, clinical implications and lessons for future trials.
T he Dual Chamber and VVI Implantable Defibrillator (DAVID) trial randomized 506 patients and tested the hypothesis that the dual-chamber pacing mode would produce improved hemodynamics and would in turn reduce congestive heart failure, heart failure hospitalizations, heart failure deaths, atrial fibrillation, strokes, ventricular arrhythmias, and total mortality compared to backup ventricular pacing in patients indicated for implantable defibrillator therapy. Patients had either primary prevention indications (47%) or secondary prevention indications (53%) for implantable defibrillator therapy but had no indications for bradycardia pacemaker support. All the patients had moderate to severe left ventricular dysfunction with a left ventricular ejection fraction of 40% or less (mean = 27%) and were consistently treated with angiotensin converting enzyme inhibitors or angiotensin II receptor blockers (86%) and beta adrenergic blocking agents (85%). ⋯ The more important question is what is the optimal pacing mode in these patients? The AAIR mode is under investigation in the DAVID II study in an attempt to identify a pacing mode that preserves atrio-ventricular synchrony, normal atrio-ventricular timing, prevents bradycardia and also prevents right ventricular stimulation. Caution should be taken to not directly apply these results to patients with either an indication for pacemaker therapy or to patients with an indication for cardiac resynchronization therapy since patients from neither population were included. However, considering the large magnitude of the deleterious effects associated with dual chamber pacing in the DAVID trial future studies should explore the possibility that left ventricular stimulation may be the only pacing mode capable of preventing bradycardia without increasing death and congestive heart failure.
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Card Electrophysiol Rev · Sep 2003
Randomized Controlled Trial Comparative Study Clinical TrialBiphasic versus monophasic shock waveform for conversion of atrial fibrillation.
Cardioversion of atrial fibrillation (AF) using traditional monophasic shock waveform is unsuccessful in up to 20% of cases, and often requires several shocks of up to 360 J. Based on the success with biphasic shock waveform in converting ventricular fibrillation, it was postulated that biphasic shocks would allow cardioversion with lower energy. In a international multicenter, double-blind, randomized trial of 203 patients, damped sine wave monophasic shocks were compared with impedance-compensated truncated exponential biphasic waveform shocks. ⋯ Biphasic shocks converted AF present for less than 48 hours with 80% efficacy, but conversion of AF present for more than 48 hours and more than 1 year the success rate was only 63 and 20%, respectively. The results of this study is similar to other investigations comparing biphasic and monophasic shock waveforms for conversion of atrial fibrillation. We recommend starting with biphasic energy of 100 J for atrial fibrillation of less than 48 hours duration, but using higher energies (150 J, 200 J or greater) when AF has been present for longer periods.
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Card Electrophysiol Rev · Jun 2003
Randomized Controlled Trial Comparative Study Clinical TrialRate-control versus conversion strategy in postoperative atrial fibrillation: trial design and pilot study results.
Atrial fibrillation (AF) remains a frequent complication of cardiac surgery. The optimal treatment strategy has not been established. Retrospective studies have suggested that a primary rate-control strategy may be equivalent to a strategy that restores sinus rhythm. ⋯ In conclusion, this pilot study shows little difference between a rate-control strategy and a strategy to restore/maintain sinus rhythm. Regardless of the strategy, majority of patients will be in sinus rhythm after two months. A larger randomized, controlled study is needed to assess the impact of restoration of sinus rhythm on length of stay.
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Card Electrophysiol Rev · Jun 2003
Randomized Controlled Trial Comparative Study Clinical TrialCombination therapy for prevention of atrial fibrillation after coronary artery bypass surgery: a randomized trial of sotalol and magnesium.
Atrial Fibrillation (AF) is a common complication of coronary artery bypass surgery reported to occur in 20-40% of patients. Sotalol alone and magnesium alone have been shown to decrease the incidence of AF. The aim of this study was to evaluate the efficacy of these two agents, alone or in combination, to reduce postoperative AF. ⋯ The incidence of AF after coronary surgery was significantly reduced by the administration of sotalol alone and magnesium alone. The incidence of postoperative AF was further reduced by combining the two pharmacological agents.