Adrenergic coronary vasoconstriction during myocardial hypoperfusion
Jorge, P.A.; Abdalla, L.A.
Arquivos Brasileiros de Cardiologia 52(4): 201-204
1989
ISSN/ISBN: 0066-782X PMID: 2557812 Document Number: 337615
The intramural branches of the coronary arteries of dogs were studied using venilite casts. The intramyocardial vessels have a general pattern with straight branches that cross from the epicardium toward the endocardium. Many branches were observed throughout the extension of these vessels, mainly in the subendocardium, where there is a rich interconnecting plexus. Some branches divides immediately in the subepicardium. These anatomic findings concur with the observations that the subendocardium is more susceptible to ischemia, as it is dependent on an extensive vascularization. These anatomic findings indicate that during constant underperfusion, the alpha adrenergically mediated vasoconstriction of the subepicardial vessels have an unexpected beneficial effect because of decreased transmural steal.