Cardiac actions in the dog of a new antagonist of adrenergic excitation which does not produce competitive blockade of adrenoceptors.
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TLDR
It is concluded that the cardiac actions of amiodarone are not produced by competitive blockade of β‐adrenoceptors.Abstract:
1. The cardiac actions of amiodarone, a benzofuran derivative used in the treatment of angina pectoris, have been compared with those of (±)-propranolol in anaesthetized dogs.
2. After three successive intravenous injections of propranolol, 0·5 mg/kg, had reduced the heart rate by 25%, a fourth dose had no further negative chronotropic action, but amiodarone, 10 mg/kg intravenously, at this point reduced the heart rate by 23%.
3. Amiodarone, 10 mg/kg intravenously, reduced, but did not abolish, cardiac responses to isoprenaline, 2 μg/kg intravenously. Subsequent successive injections of 10 mg/kg of amiodarone did not further block the responses to isoprenaline, but propranolol, 1 mg/kg intravenously, abolished them.
4. Amiodarone reduced cardiac chronotropic and inotropic responses to glucagon, which were not affected by propranolol.
5. Cardiac output was increased 5 min after amiodarone, 10 mg/kg intravenously, but at 10 min and thereafter it did not differ from control values. Propranolol, 1 mg/kg intravenously, reduced cardiac output by 17% at 5 min, and by 30% after 30 min.
6. From this and other evidence which is discussed, it is concluded that the cardiac actions of amiodarone are not produced by competitive blockade of β-adrenoceptors.read more
Citations
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Journal ArticleDOI
The use of intravenous amiodarone in the acute therapy of life-threatening tachyarrhythmias
Alan H. Kadish,Fred Morady +1 more
TL;DR: IV amiodarone may be poten- tially useful in the therapy of patients with frequent or incessant arrhythmias, and there may be patients with severe systemic ill- nesses in whom IV therapy may be the only method available for delivering an antiarrhythmic agent.
Journal ArticleDOI
Comparison of the in vivo electrophysiological and proarrhythmic effects of amiodarone with those of a selective class III drug, sematilide, using a canine chronic atrioventricular block model.
Hiroshi Yoshida,Atsushi Sugiyama,Yoshioki Satoh,Yuko Ishida,Masahiko Yoneyama,Kiyotaka Kugiyama,Keitaro Hashimoto +6 more
TL;DR: It is suggested that IKr channel inhibition by amiodarone with its additional ion channel blocking action may contribute to the prevention of TdP.
Journal ArticleDOI
Cardiopulmonary effects of chronic amiodarone therapy in the early postoperative course of cardiac surgery patients.
E. M. Tuzcu,James D. Maloney,B. H. Sangani,Martin Masterson,K. D. Hocevar,Leonard R. Golding,N. J. Starr,Joseph A. Golish,Lon W. Castle,Victor A. Morant +9 more
TL;DR: The early postoperative course of 28 consecutive patients who underwent cardiac surgery while on amiodarone therapy and those who underwent similar surgery and were later given amodarone were compared.
Journal ArticleDOI
New antiarrhythmic drugs: tocainide, mexiletine, flecainide, encainide, and amiodarone.
TL;DR: Tocainide, mexiletine, flecainide and amiodarone are five antiarrhythmic agents that have been recently approved by the Food and Drug Administration for general use in the treatment of ventricular arrhythmias.
References
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Journal ArticleDOI
A study of the adrenotropic receptors
TL;DR: Experiments described in this paper indicate that although there are two kinds of adrenotropic receptors they cannot be classified simply as excitatory or inhibitory since each kind of receptor may have either action depending upon where it is found.
Journal ArticleDOI
The effect of amiodarone, a new anti‐anginal drug, on cardiac muscle
TL;DR: It was concluded that amiodarone had effects on cardiac action potentials similar to those which occur after thyroidectomy.
Journal ArticleDOI
Glucagon Its Enhancement of Cardiac Performance in the Cat and Dog and Persistence of its Inotropic Action Despite Beta-Receptor Blockade with Propranolol
TL;DR: In the dog, myocardial performance was markedly augmented by the administration of glucagon, 50 μg/kg iv, as indicated by an average increase of 72.2±18.8% in force recorded by a strain gauge arch, despite an average decrease of 3.8±1.2 cm H2O (P < 0.02) in left ventricular end-diastolic pressure.
Journal ArticleDOI
Cardiac Actions of Glucagon
TL;DR: The results of these studies are discussed in reference to the known metabolic actions of glucagon and the catecholamines and the possibility that they both share a common mechanism of action mediated through an increase in the intracellular concentration of cyclic 3′,5′ AMP.