Author + information
- Received November 24, 1986
- Revision received March 2, 1987
- Accepted March 3, 1987
- Published online August 1, 1987.
- ↵*Address for reprints: Gerald R. Marx, MD, Department of Pediatrics, University of Arizona, Health Sciences Center, Tucson, Arizona 85724.
The purposes of this study were to determine the ability of pulsed Doppler echocardiography to consistently and accurately measure cardiac output during exercise, and to measure the exercise factor by Doppler methodology when oxygen consumption was simultaneously measured. Thirty-four healthy young adolescent male volunteers (mean age 13 years) were recruited. Submaximal exercise was performed by supine bicycle ergometry. Cardiac output was calculated as mean velocity × cross-sectional area. Successful rest and exercise determinations of cardiac output were obtained in 81% (n = 52) of the studies.
Mean cardiac output increased from 4.6 to 8.9 liters/min (p < 0.001) during exercise and mean oxygen consumption increased from 212 to 899 ml/min (p < 0.001). Doppler-estimated rest and exercise cardiac outputs correlated well with simultaneously measured oxygen consumption (r = 0.89, SEE = 1.2 liters/min; y = 0.006 × 3.2 liters/min). Mean exercise factor was 6.4 (1.2 SD). Twenty-six pairs of rest and exercise cardiac output determinations by Doppler technique and indirect Fick method were simultaneously compared in a subset population (r = 0.86, SEE = 1.4 liters/min; slope = 0.93, y intercept = 1.4 liters/min). Results of this study demonstrate that cardiac output and exercise factor can be estimated by pulsed Doppler echocardiography during exercise.
with the technical assistance of SCOTT M. KINZER, MS
- Received November 24, 1986.
- Revision received March 2, 1987.
- Accepted March 3, 1987.
- American College of Cardiology Foundation