Comparison of acute electrophysiological effects of amiodarone and its metabolite desethylamiodarone in Langendorff perfused guinea pig hearts
| Autor: | S. Nagl, M. Windisch, U. Eggenreich, Helmut A. Tritthart, U. Stark, Gerhard Stark, Ernst Pilger, K. Kral, M. Vicenzi |
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| Rok vydání: | 1991 |
| Předmět: |
Male
Cardiac Complexes Premature medicine.medical_specialty Refractory Period Electrophysiological Physiology Refractory period Metabolite Guinea Pigs Amiodarone In Vitro Techniques Electrocardiography chemistry.chemical_compound Heart Rate Physiology (medical) Internal medicine Heart rate medicine Animals Repolarization business.industry Heart Atrioventricular node Electric Stimulation Electrophysiology Perfusion medicine.anatomical_structure Endocrinology chemistry Cardiology Female Electrical conduction system of the heart Cardiology and Cardiovascular Medicine business medicine.drug |
| Zdroj: | Basic Research in Cardiology. 86:136-147 |
| ISSN: | 1435-1803 0300-8428 |
| DOI: | 10.1007/bf02190546 |
| Popis: | During long-term treatment with amiodarone, slowing of conduction through the atrioventricular node, a prolongation of the QT-interval, and a prolongation of the atrial and ventricular myocardial refractoriness always developed. During short-term treatment, these effects were not found, except for depression of the AV-nodal conduction. This led to the suggestion that the electrophysiological effects of amiodarone during long-term treatment might be partly the result of the accumulation of its metabolite desethylamiodarone. Therefore, we examined the electrophysiological effects of amiodarone and desethylamiodarone on conduction and refractoriness in isolated spontaneously beating guinea pig hearts perfused by the method of Langendorff. Within 1 h of perfusion, desethyl-amiodarone caused a more pronounced prolongation of the AV-nodal, His-bundle, and intraventricular conduction intervals than did amiodarone. Desethylamiodarone, but not amiodarone led to a prolongation of the QT-interval. The refractoriness of sinoatrial-, AV-nodal conduction, and of the atrial myocardium were significantly more prolonged by amiodarone than by desethylamiodarone. Both compounds showed a comparable strong rate-dependent effect on AV-nodal refractoriness. The ventricular refractoriness was similarily prolonged by either compound. These results show that for the class-III effects (i.e., prolongation of repolarization period) observed under chronic treatment of amiodarone the metabolite desethylamiodarone may be responsible. Desethylamiodarone also exerts more pronounced effects on the fast-channel-dependent parts of the conduction system than does amiodarone, a fact indicated by a higher prolongation of His-bundle and intraventricular conduction. |
| Databáze: | OpenAIRE |
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