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 0.61±0.09 mm Hg/ml/min/kg. In the control group heart rate decreased with age from 170±8 to 76±6 beats/min, the cardiac output/body weight ratio was reduced from 195±18 to 118±22 ml/min/kg, MAP increased from 65±6 to 92±8 mm Hg, and total peripheral resistance rose from 0.32±0.09 to 0.77±0.08 mm Hg/ml/min/kg. In summary, inappropriate elevation of the cardiac output/body weight ratio during growth caused a deviation toward higher levels of the blood pressure maturation curve and inhibited the natural rise in total peripheral resistance. We conclude that the heart may generate high blood pressure during development, but this pure cardiogenic hypertension does not trigger a secondary rise in total peripheral resistance.
|Number of pages||6|
|Publication status||Published - 1988|
ASJC Scopus subject areas
- Internal Medicine