The effect of amiodarone, a new anti‐anginal drug, on cardiac muscle
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It was concluded that amiodarone had effects on cardiac action potentials similar to those which occur after thyroidectomy.Abstract:
1. Amiodarone (2-butyl, 3-(4-diethylaminoethoxy, 3,5-diiodo, benzoyl) benzofuran hydrochloride), an anti-anginal drug which causes coronary dilatation and depresses myocardial oxygen consumption, was found to protect anaesthetized guinea-pigs against ouabain-induced ventricular fibrillation.
2. A 5% (73·4 mM) solution of amiodarone had no local anaesthetic action on guinea-pig skin.
3. Amiodarone, 20 mg/kg (29·4 μmol/kg) given daily for 6 weeks intraperitoneally, had no effect on the resting potential or action potential height, and only a small effect on the maximum rate of depolarization, of isolated rabbit atrial or ventricular muscle fibres as shown by intracellular recording. It caused a considerable prolongation of the action potential in both tissues.
4. Simultaneous administration of thyroxine (5 μg; 6·26 nmol), given daily for 3 weeks intraperitoneally, prevented the prolongation by amiodarone of the duration of the action potential.
5. Treatment of rabbits with 20 mg/kg of amiodarone daily intraperitoneally for 6 weeks had no effect on the weight of the thyroid gland, but was associated with a reduction in body growth rate.
6. Treatment of rabbits with 10 mg/kg (60·3 μmol/kg) of potassium iodide (equal in its iodine content to that of 20 mg/kg of amiodarone), given daily for 6 weeks intraperitoneally, had no effect on body growth rate or the duration of cardiac action potentials.
7. It was concluded that amiodarone had effects on cardiac action potentials similar to those which occur after thyroidectomy.read more
Citations
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Antiarrhythmic Agents: The Modulated Receptor Mechanism of Action of Sodium and Calcium Channel-Blocking Drugs
L M Hondeghem,B G Katzung +1 more
TL;DR: This review concentrates on the antiarrhythmic drug literature pertinent to an evaluation of the modulated receptor hypothesis: lidocaine, procainamide, quinidine, diphenylhydantoin, and propranolol.
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Clinical efficacy and electrophysiology during long-term therapy for recurrent ventricular tachycardia or ventricular fibrillation.
James J. Heger,Eric N. Prystowsky,Warren M. Jackman,Gerald V. Naccarelli,K. A. Warfel,Robert L. Rinkenberger,Douglas P. Zipes +6 more
TL;DR: It is concluded that amiodarone is effective for long-term therapy of recurrent ventricular tachyarrhythmias, that induction of arrhythmia during therapy does not always predict efficacy, and that side effects are frequent but do not usually limit therapy.
Journal ArticleDOI
Clinical efficacy of amiodarone as an antiarrhythmic agent
Mauricio B. Rosenbaum,Pablo A. Chiale,M. Susana Halpern,Gerardo J. Nau,Julio Przybylski,Raúl J. Levi,Julio O. Lázzari,Marcelo V. Elizari +7 more
TL;DR: Amiodarone proved safe in patients with severe congestive heart failure and severe myocardial damage and liberates patients from a rigid hourly schedule and provides for continuous antiarrhythmic control, days and even weeks after treatment is discontinued.
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Spontaneous Conversion and Maintenance of Sinus Rhythm by Amiodarone in Patients With Heart Failure and Atrial Fibrillation Observations from the Veterans Affairs Congestive Heart Failure Survival Trial of Antiarrhythmic Therapy (CHF-STAT)
Prakash Deedwania,Bramah N. Singh,Kenneth A. Ellenbogen,Susan G. Fisher,Ross D. Fletcher,Steven N. Singh +5 more
TL;DR: In patients with CHF, amiodarone has a significant potential to spontaneously convert patients in AF to sinus rhythm, with patients who convert having a lower mortality rate than those who do not, and the drug prevented the development of new-onset AF and significantly reduced the VR in those with persistent AF.
Journal ArticleDOI
A third class of anti-arrhythmic action: Effects on atrial and ventricular intracellular potentials, and other pharmacological actions on cardiac muscle, of MJ 1999 and AH 3474
TL;DR: It was concluded that direct depression of depolarization could have contributed little to the protection against ouabain‐induced fibrillation, and it is suggested that this effect contributes to anti‐arrhythmic activity.
References
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Journal ArticleDOI
THE EFFECTS ON CARDIAC MUSCLE OF β-RECEPTOR ANTAGONISTS IN RELATION TO THEIR ACTIVITY AS LOCAL ANAESTHETICS
Journal ArticleDOI
The effect of altered thyroid state on atrial intracellular potentials
TL;DR: A group of rabbits was made hypothyroid by thyroidectomy, and another group was injected daily with L‐thyroxine until alterations in thyroid state were confirmed by measurement of heart weight and of plasma iodine.
Journal Article
Biological comparison of local anaesthetics.
Edith Bülbring,Isabella Wajda +1 more
TL;DR: It was observed that when adrenaline was added to procaine and the mixture was compared with cocaine by the guinea-pig method, the log dose-effect lines became parallel and it was suggested to use procaine as a standard of comparison.
Journal Article
Pharmacology of amiodarone, and anti-anginal drug with a new biological profile.
Journal ArticleDOI
The relevance of β-receptor blockade to ouabain-induced cardiac arrhythmias
TL;DR: In isolated rabbit atria (–)‐, (+)‐ and (±)‐propranolol, and I.C.I. 50172, which has hardly any local anaesthetic activity, greatly reduce the rate of rise of the intracellularly recorded action potential at concentrations which have no significant effect on electrical threshold, contractions, spontaneous frequency, maximum driving frequency, repolarization time or conduction velocity.