Medizinische Universität Graz Austria/Österreich - Forschungsportal - Medical University of Graz
Gewählte Publikation:
Stark, G; Windisch, M; Haller, EM; Stark, U; Pieber, T; Pilger, E; Krejs, GJ; Tritthart, HA.
Acute effects of amiodarone on ultrastructure and electrical activity of isolated guinea pig hearts.
Cardiovasc Res. 1991; 25(10):807-814
Doi: 10.1093/cvr/25.10.807
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- Co-Autor*innen der Med Uni Graz
- Haller-Schober Eva-Maria
- Krejs Günter Josef
- Pieber Thomas
- Pilger Ernst
- Tritthart Helmut
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- Abstract:
- Study objective - The aim was to evaluate the effects of tissue concentration of amiodarone on ultrastructure and electrical activity in isolated spontaneously beating Langendorff perfused guinea pig hearts. Design - Group 1: The influence of 10-mu-M amiodarone over a period of 1 h in a non-recirculated perfusate on conduction intervals, heart rate, creatine kinase concentration in the coronary effluent, coronary flow, and drug accumulation was determined. Group 2: Ultrastructural changes after 30 min and 60 min perfusion with amiodarone were examined. Group 3: Cardiac refractoriness was evaluated following 30 min and 60 min of perfusion with amiodarone. Experimental preparations - Isolated hearts of guinea pigs (200-300 g) were used: group 1, n = 6 animals; group 2, n = 3 for each time span; and group 3, n = 6 for each time span. Measurements and main results - A steady state for the effects of amiodarone on atrioventricular and intraventricular conduction [(SEM 5)%, p < 0.01; (12)%, p < 0.01, respectively] and on heart rate [-30(9)%, p < 0.01] was reached after 15 min, and on His bundle conduction [(17)%, p < 0.01] after 30 min. QT duration was not affected throughout the duration of the experiment. Cardiac refractoriness was significantly prolonged following 30 min perfusion with 10-mu-M amiodarone, and was further significantly increased following 60 min perfusion. Amiodarone tissue concentration increased to 365(39) nmol.g-1 wet weight, and this was accompanied by an increase in creatine kinase concentration in the coronary effluent. Coronary flow stayed constant throughout the whole experiment. At the end of the experiment electron microscopic examination of the myocardium of the left ventricle showed accumulation, fusion, and vacuolisation of mitochondria, and perinuclear oedema. Conclusions - These observations suggest that amiodarone, as well as exerting acute electrophysiological effects, creates ultrastructural changes which probably contribute to its effectiveness in arrhythmias caused by scarred myocardium.
- Find related publications in this database (using NLM MeSH Indexing)
- Amiodarone - pharmacokinetics Amiodarone - pharmacology
- Animals -
- Depression, Chemical -
- Electric Stimulation -
- Guinea Pigs -
- Heart - drug effects
- Heart Conduction System - drug effects
- Heart Rate - drug effects
- Heart Ventricles - ultrastructure
- Myocardium - metabolism
- Organ Culture Techniques -
- Find related publications in this database (Keywords)
- Amiodarone
- Myocardial Ultrastructure
- Refractoriness
- Cardiac Conduction
- Isolated Heart Preparation