Hypertension, Vol 12, 295-300, Copyright © 1988 by American Heart Association
F Magrini, N Roberts, G Branzi, C Mondadori, P Reggiani, M Ciulla and R Meazza
The purpose of this study was to evaluate whether the heart can induce high
blood pressure by maintaining an inappropriately elevated cardiac
output/body weight ratio during growth. Direct (femoral artery) mean
arterial pressure (MAP), heart rate, cardiac output/body weight ratio (as
defined by M-mode echocardiography), and total peripheral vascular
resistance were measured and calculated every 2 months in nine conscious
dogs during development from 2 to 10 months of age. In four dogs a J-shaped
catheter for atrial pacing was chronically implanted at the age of 3
months, and their hearts were permanently paced at 130 beats/min until
maturity. The aim of atrial pacing was to prevent the natural slowing of
the heart rate and, consequently, to maintain a cardiac output/body weight
ratio that was inappropriately high in relation to age during growth. Five
dogs were studied as controls. No hemodynamic differences were observed
until the age of 4 months. From the age of 5 to 10 months heart rate was
kept at 130 beats/min by atrial pacing in the atrially paced group, and the
mean cardiac output/body weight ratio did not decrease (196 +/- 24 vs 191
+/- 34 [SE] ml/min/kg). MAP rose from 62 +/- 4 to 116 +/- 8 mm Hg, and
total peripheral resistance increased from 0.34 +/- 0.07 to to 0.61 +/-
0.09 mm Hg/ml/min/kg.(ABSTRACT TRUNCATED AT 250 WORDS)
ARTICLES
Cardiogenic hypertension in maturing dogs
Istituto di Clinica Medica Generale e Terapia Medica, Universita di Milano, Italy.
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