Cardiac vasculature and flow during pressure-overload hypertrophy.
Am J Physiol
; 251(5 Pt 2): H1031-7, 1986 Nov.
Article
em En
| MEDLINE
| ID: mdl-2946241
ABSTRACT
The effects of pressure-overload hypertrophy (H) on myocardial blood flow and microvasculature were studied in the porcine left ventricle. Hypertrophy was produced in nine adult pigs by an aortic cuff constriction of the ascending aorta. Eight pigs served as controls. After 30 days the aortic cuff was released, and the hypertrophy group was studied 1 day postrelease. The degree of hypertrophy, determined by left ventricular-to-body weight ratio, was 45%. With hypertrophy, left ventricular blood flows were normal at rest. During exercise with adenosine infusion, myocardial blood flow to the endomyocardium was reduced compared with the control (C) group (H = 4.02 +/- 0.35, P less than 0.05; C = 5.33 +/- 0.41 ml X min-1 X g-1). Minimal coronary vascular resistance in the endomyocardium was increased during exercise with adenosine in the hypertrophy group compared with the control group. Anatomic studies revealed that hypertrophy causes a reduction in the endomyocardial capillary density (H = 1,654 +/- 168, P less than 0.025; C = 2,168 +/- 106, no./mm2) with a similar trend noted for the transmural arteriolar density. Arteriolar media wall cross-sectional area was unaffected by the pressure overload. These results indicate that changes in the vascular bed do not parallel myocyte growth during pressure-overload hypertrophy. The resultant anatomic imbalance compromises endomyocardial flow, making this region vulnerable to ischemia.
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Base de dados:
MEDLINE
Assunto principal:
Pressão Sanguínea
/
Cardiomegalia
/
Circulação Coronária
/
Vasos Coronários
Tipo de estudo:
Etiology_studies
Limite:
Animals
Idioma:
En
Ano de publicação:
1986
Tipo de documento:
Article