ISSN:0268-4705    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

Debate exists as to the proper site for initiating antiarrhythmic therapy for supraventricular tachyarrhythmias and other benign forms of ectopy: inpatient versus outpatient. Rapid detection of efficacy and adverse effects, with immediate correction of the latter, favors the inpatient site. Convenience and, under most circumstances, lower cost favor the outpatient site. Circumstances under which adverse event rates, including proarrhythmia, are expectedly low, would favor outpatient initiation. So would the use of an agent whose elimination half-life is so long as to render in-hospital monitoring to steady state highly impractical. Accordingly, outpatient initiation would be suitable for patients without structural heart disease receiving class IC drugs, patients with low risk for torsades de pointes receiving selected class III agents, in whom data in the literature are supportive (as has occurred with sotalol and azimilide), and patients who are to receive amiodarone. Transtelephonic electrocardiographic monitoring can be used to facilitate assessment in the outpatient setting. Inpatient initiation should be considered for patients with underlying sinus node or atrioventricular conduction disturbances, for patients with significant structural heart disease, for patients receiving a drug whose proarrhythmia may be idiosyncratic (eg,quinidine), and for patients who are to begin an antiarrhythmic drug while in a supraventricular tachyarrhythmia in whom sinus rhythm has not previously been seen. The relative costs and benefits of the approach chosen will be a reflection of the probability that a drug with a chosen mechanism will cause an adverse outcome in a patient with a specific clinical substrate during the period chosen for monitoring.

ISSN:0268-4705    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

In this review, the up-to-date understanding of the molecular basis of primary ventricular arrhythmias will be outlined. Two disorders have recently been well described at the molecular level, the long QT syndromes and Brugada syndrome, and in this paper we review the current scientific knowledge of each disease.

ISSN:0268-4705    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

Atrial fibrillation is the most common sustained arrhythmia likely to be encountered in clinical practice. It is associated with significant morbidity and mortality. The treatment of patients with atrial fibrillation can be complex and costly, especially when patients are hospitalized for acute management of this arrhythmia. In this review, we summarize current approaches to the acute management of atrial fibrillation with an emphasis on the most cost-effective approaches. We review acute methods of heart rate control and cardioversion, including pharmacologic and other minimally invasive strategies. We believe that the most cost-effective approaches may require the use of standardized clinical pathways. This may help to ensure that patients with acute atrial fibrillation receive the most effective and efficient care.

ISSN:0268-4705    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

After its introduction in 1987, radiofrequency catheter ablation became established as a safe and effective therapy for the cure of many cardiac arrhythmias in people. The possibility of assessing the relationship between the anatomical target and the electrophysiologic changes produced by radiofrequency pulse delivery has also provided significant improvement in the physician's knowledge of the pathophysiology of the underlying rhythm disturbance. Nowadays, using this therapy, success rates well above 90% with recurrence rates lower than 5% are expected after treatment of most regular supraventricular arrhythmias. As catheter ablation techniques develop, success rates in the range of those obtained for regular supraventricular arrhythmias are expected in the future in the treatment of regular ventricular and irregular supraventricular arrhythmias.

ISSN:0268-4705    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

In the past 2 years, significant advances have been made in class III antiarrhythmic drug therapy. In patients with ventricular arrhythmias and implantable cardioverter defibrillators (ICDs), antiarrhythmic agents are increasingly being used as adjunct therapy to decrease the frequency of ICD discharges. Sotalol was recently shown to be effective in reducing tachyarrhythmias in patients with ICDs. Intravenous amiodarone is being used for the acute treatment of unstable ventricular arrhythmia and is being investigated for the treatment of acute out-of-hospital cardiac arrest. Class III agents are increasingly being used for prophylaxis in patients who have atrial fibrillation or atrial flutter, and data point to an important role for these agents in reducing supraventricular tachyarrhythmias after cardiac surgery. Future studies will need to directly compare these agents with pure anti-adrenergic maneuvers in postoperative patients. In addition to terminating atrial fibrillation and atrial flutter, ibutilide significantly reduces human atrial defibrillation thresholds and increases the percentage of patients who can be cardioverted from atrial fibrillation to sinus rhythm. The US Food and Drug Administration is expected to approve dofetilide for clinical use soon, and it is currently reviewing azimilide (which seems to be devoid of frequency-dependent effects on repolarization) for prophylaxis against atrial fibrillation and atrial flutter. Dronedarone, tedisamal, and trecetilide are now under active study intended to determine their usefulness in patients with cardiac arrhythmias. Experimental studies are ongoing to identify pharmacologic agents that will selectively prolong repolarization in the atria without exerting electrophysiologic effects in the ventricles.

ISSN:0268-4705    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

A number of publications and clinical trials on the management of atrial fibrillation (AF) deal with this arrhythmia as if it represents a single entity. As a result, advances made in recent years have not affected the way AF patients are treated in general practice except, perhaps, for the use of warfarin in anticoagulation. Therefore, there is a need for a classification system and for uniformity in the nomenclature used. The two terms currently used to describe AF, paroxysmal and chronic, require a time frame. It is proposed that if an AF episode lasts longer than 7 days, the condition should be considered chronic. For the first symptomatic, non–self-terminating episode that is fewer than 7 days long, the term recent onset AF may be used, or recent discovery if the AF is asymptomatic or if the duration cannot be determined. Attacks of paroxysmal AF may differ in their duration, frequency, and functional tolerance. In the classification system described, three clinical aspects of paroxysmal AF were isolated in such a way as to have implications for therapy. This classification system was found to be useful for characterizing different subsets of patients with AF.

ISSN:0268-4705    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

Risk for stroke in patients with atrial fibrillation (AF) is highly heterogenous. Increasing age, history of diabetes, hypertension, previous transient ischemic attack or stroke, and poor ventricular function are independent risk factors for stroke in patients with AF. Accordingly, some groups of patients with AF have low risk and some have high risk. In general, patients at high risk benefit most from anticoagulation therapy with warfarin. In general, if a patient is younger than 65 years of age and has none of the defined risk factors, the stroke rate without prophylaxis (aspirin or warfarin) is low. In patients 65 to 75 years of age with no risk factors, the risk for stroke is low with either aspirin or warfarin therapy; the choice is left to the caretaking physician. All patients older than 75 years and all patients of any age who have risk factors obtain striking benefit from the use of anticoagulation with warfarin. This benefit far outweighs any risk for major hemorrhage.

ISSN:0268-4705    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

Amiodarone is an antiarrhythmic agent commonly used in the treatment of supraventricular and ventricular tachyarrhythmias. This article reviews the results and clinical implications of primary and secondary prevention trials in which amiodarone was used in one of the treatment arms. Key post–myocardial infarction primary prevention trials include the European Myocardial Infarct Amiodarone Trial (EMIAT) and the Canadian Amiodarone Myocardial Infarction Trial (CAMIAT), both of which demonstrated that amiodarone reduced arrhythmic but not overall mortality. In congestive heart failure patients, amiodarone was studied as a primary prevention strategy in two pivotal trials: Grupo de Estudio de la Sobrevida en la Insuficiencia Cardiac en Argentina (GESICA) and Amiodarone in Patients With Congestive Heart Failure and Asymptomatic Ventricular Arrhythmia (CHF-STAT). Amiodarone was associated with a neutral overall survival and a trend toward improved survival in nonischemic cardiomyopathy patients in CHF/STAT and improved survival in GESICA. In post–myocardial infarction patients with nonsustained ventricular tachycardia and a depressed ejection fraction, the Multicenter Automatic Defibrillator Implantation Trial (MADIT) demonstrated that implantable cardioverter-defibrillators (ICD) statistically improved survival compared to the antiarrhythmic drug arm, most of whose patients were taking amiodarone. In patients with histories of sustained ventricular tachycardia or ventricular fibrillation, the Cardiac Arrest Study in Seattle: Conventional Versus Amiodarone Drug Evaluation (CASCADE) trial demonstrated that empiric amiodarone lowered arrhythmic recurrence rates compared to other drugs guided by serial Holter or electrophysiologic studies. However, arrhythmic death rates were high in both treatment arms of the study. Several secondary prevention trials, including the Antiarrhythmics Versus Implantable Defibrillators Study (AVID), the Canadian Implantable Defibrillator Study (CIDS), and the Cardiac Arrest Study Hamburg (CASH), have demonstrated the superiority of ICD therapy compared to empiric amiodarone in improving overall survival. Based on the above findings, amiodarone is safe to use in post–myocardial infarction and congestive heart failure patients that need antiarrhythmic therapy. Although amiodarone is effective in treating malignant arrhythmias, high-risk patients should be considered for an ICD as frontline therapy.

ISSN:0268-4705    

出版商:OVID    

年代:2000

数据来源: OVID