ISSN:0091-2700    

DOI:10.1002/j.1552-4604.1991.tb03670.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

ISSN:0091-2700    

DOI:10.1002/j.1552-4604.1991.tb03671.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

Cardiac arrhythmias are generated as the result of disorders of automaticity or of impulse conduction. Regardless of the mechanism, calcium is likely to he involved, although calcium antagonists are rarely useful antiarrhythmics in ventricular arrhythmias. Myocardial cells that do not ordinarily initiate action potentials may do so when they are partially depolarized, giving rise to an ectopic focus. Early afterdepolarizations (EADs) are also induced in cardiac cells by partial depolarization, whereas delayed afterdepolarizations (DADs) are induced by Ca++overloading. EADs may be the initiating mechanism of torsade de pointes, a complication of QT prolongation associated with quinidine therapy. Both in the animal model and in humans, treatment with magnesium, isoproterenol, or pacing, all of which suppress EADs, will also suppress torsade de pointes. Ventricular tachycardia is a manifestation of ordered re‐entry, and may be exacerbated by antiarrhythmics, especially class 1c drugs. In the individual patient, prediction of proarrhythmia is not possible. The risk of proarrhythmia is increased in patients with episodes of sustained ventricular tachycardia or with significant left ventricular dysfunctio

ISSN:0091-2700    

DOI:10.1002/j.1552-4604.1991.tb03672.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

Amiodarone is a unique antiarrhythmic agent originally developed as a vasodilator. Classified electrophysiologically as a Type III antiarrhythmic, it also has both nonspecific antisympathetic and direct, fast channel‐membrane effects. Hemodynamic effects of orally administered amiodarone (a negative inotropic agent) are usually negligible, and are usually compensated for by induced vasodilation. Effects on thyroid and hepatic function may help to explain some of the unique pharmacologic as well as toxicologic effects of the drug. Amiodarone is poorly bioavailable (20–80%) and undergoes extensive enterohepatic circulation before entry into a central compartment. The principal metabolite, mono‐n‐desethyl amiodarone is also an antiarrhythmic. From this central compartment, it undergoes extensive tissue distribution (exceptionally high tissue/plasma partition coefficients). The distribution half‐life of amiodarone out of the central compartment to peripheral and deep tissue compartments (t1/2α) may be as short as 4 hours. The terminal half‐life (t1/2β) is both long and variable (9–77 days) secondary to the slow mobilization of the lipophilic medication out of (primarily) adipocytes. A pharmacokinetically based loading scheme is described, and data suggesting a role for routine amiodarone plasma level

ISSN:0091-2700    

DOI:10.1002/j.1552-4604.1991.tb03673.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

ISSN:0091-2700    

DOI:10.1002/j.1552-4604.1991.tb03674.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

Despite significant advances in recent years in the diagnosis and treatment of congestive heart failure, sudden unexpected cardiac death is still considered a major epidemiologic problem among those patients. This article lists some of the predisposing factors to the development of cardiac arrhythmias and sudden death in patients with congestive heart failure. These include electrolyte or autonomic nervous system inbalance, the use of certain anti‐arrhythmic drugs, or intermittent myocardial ischemia. This paper shows that an advanced degree of left ventricular dysfunction and the preference frequent or complex ventricular arrhythmias appear to be major predictors of total and sudden mortality among patients with congestive heart failure. A screening of 24 hours ambulatory Holter monitor recording appears to be useful in identifying patients at risk of sudden cardiac deat

ISSN:0091-2700    

DOI:10.1002/j.1552-4604.1991.tb03675.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

ISSN:0091-2700    

DOI:10.1002/j.1552-4604.1991.tb03676.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

ISSN:0091-2700    

DOI:10.1002/j.1552-4604.1991.tb03677.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

ISSN:0091-2700    

DOI:10.1002/j.1552-4604.1991.tb03678.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

A group of 34 consecutive patients with coronary artery disease (n = 29) or dilated cardiomyopathy (n = 5) (3 women, 31 men, age 38–80 yr) who had severely impaired left ventricular function (left ventricular ejection fraction ≤ 40%) and high‐grade ventricular ectopic activity (sustained or nonsustained ventricular tachycardia or ventricular fibrillation) were treated with amiodarone (mean dose: 206 mg/d) and followed for 1–117 (mean: 49) months. In the total group, there were seven sudden deaths, five deaths due to pump failure, one non‐cardiac death, and two successful heart transplantations during follow‐up. Thus the annual cardiac mortality in these carefully selected and followed patients was 8, 6%, the annual cardiac event rate was 10, 1%. The cumulative cardiac survival‐rate was 62% after 5 years and 41% after 10 years. In jive patients, treatment was interrupted after 10 to 43 months, three of the patients were alive at follow‐up and two suffered cardiac death, resulting in an annual cardiac death rate of 12% in this subgroup off treatment. Based on the results of this retrospective analysis we conclude that in patients with low left ventricular ejection fraction and nonsustained or sustained ventricular tachycardia treated with low dose amiodarone, mortality was unexpectedly low. Thus, it may be the antiarrhythmic treatment to be considered in patients with ventricular tachycardia and severe left ventricu

ISSN:0091-2700    

DOI:10.1002/j.1552-4604.1991.tb03679.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY