Echo Doppler assessment of cardiac output and its relation to growth in normal infants

Abstract

In a study of 38 normal infants, serial measurements of systemic (n = 169) and pulmonary (n = 143) blood flow were undertaken from the ages of 2 weeks to 12 months by 2-dimensional, M-mode and pulsed Doppler echocardiography. Cardiac output changed linearly (cardiac output = 0.3 × height − 0.99 liter/min), and cardiac index was validated as a means for standardizing cardiac output in infants younger than 10 to 13 months of age. Infants younger than 2 months had lower cardiac indexes and stroke volume indexes (2.6 ± 0.7 liters/min/ m 2 and 19 ± 5 ml/m 2, respectively) compared with those aged 12 months (3.2 ± 0.7 liter/min/m 2 and 25 ± 5 ml/m 2, respectively). Changes in cardiac output in individual infants over time suggest nonmorphometric modulating factors for cardiovascular function.