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Nifedipine effects in severe myocardial ischaemia in the dog due to left anterior descending coronary occlusion with left circumflex coronary artery constriction
Author(s) -
Szekeres L.,
Udvary Éva,
Végh Ágnes
Publication year - 1987
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1111/j.1476-5381.1987.tb08991.x
Subject(s) - nifedipine , cardiology , medicine , circumflex , constriction , artery , ischemia , occlusion , right coronary artery , coronary circulation , collateral circulation , anesthesia , blood flow , myocardial infarction , coronary angiography , calcium
1 The effects of nifedipine were studied in a model of local myocardial ischaemia, comprising anaesthetized thoracotomized dogs in which a critical constriction of the left circumflex coronary artery (LCX) was combined with sudden occlusion of the left anterior descending coronary artery (LAD). Since more than one coronary artery is involved in ischaemic heart disease, the model seems to reflect the clinical situation very closely. 2 In this model, infusion of 1 μg kg −1 min −1 nifedipine increased myocardial blood flow within the stenosed area served by the LCX as well as in the myocardial region supplied by the LAD, mainly in the subepicardium. Accordingly, the drug reduced ischaemic ST‐segment elevation only in the epicardium. 3 It is suggested that nifedipine directed flow to the sub‐epicardium of the ischaemic area by improving the collateral circulation. This redistribution of flow resulted in a decrease in the endo/epicardial flow ratio. 4 Nifedipine did not change the inhomogeneity of electrical activation indicating that it has no effect on the ischaemia‐induced conduction delay. At the same time nifedipine was not able to reduce either the number of extrasystoles appearing in the early postocclusion and reperfusion phase or the incidence of ventricular fibrillation occuring mainly during reperfusion.