Journal of Applied Physiology, Vol 44, Issue 1 55-58, Copyright © 1978 by American Physiological Society
Reliability of noninvlasive methods for measuring cardiac function in exercise
L. A. Wolfe, D. A. Cunningham, G. M. Davis and P. A. Rechnitzer
Externally recorded systolic time intervals (STI's), indirect (CO2
re-breathing) cardiac output, and auscultatory blood pressures were
measured during upright bicycle ergometer work in 20 healthy men, aged
24-56 yr. The subjects were studied on 2 separate days at steady-state work
loads chosen to represent light (mean heart rate (HR) = 96 beats.min-1),
moderate (HR = 118 beats.min-1) and heavy (HR = 147 beats.min-1) exercise.
In addition to determinations of cardiac output, systolic time intervals,
and blood pressure, the individual's mean systolic ejection rate (stroke
volume/left ventricular ejection time) was calculated as a measure of left
ventricular function. In general, heart-rate-corrected STI's were found to
be reliable and reproducible. Reliability coefficients for total
electromechanical systole and left ventricular ejection time ranged from
0.93 to 0.96 while those for the preejection period and its subcomponents
were between 0.63 and 0.88. The reliability of cardiac output, stroke
volume, mean systolic ejection rate, and systolic blood pressure was also
considered to be acceptable but tended to be higher during moderate and
heavy work (r = 0.85-0.95) compared to light exercise (r = 0.60-0.83).
