Key Points
- To identify the physiological variables that govern the duration of left ventricular ejection at rest and during exercise in healthy men.
- Analyzed 207 hemodynamic measurement points across 20 young male subjects at rest and during physical exercise.
- Used linear stepwise regression and factor analysis to model ejection duration as a function of heart rate, stroke index, and aortic diastolic pressure.
- Stepwise regression produced a predictive formula for ejection duration (.36646 - .00108*rate - .00036*diastolic pressure + .00076*stroke index) with a correlation coefficient of r = 0.90 and an error of estimate of 0.0155 seconds.
- Heart rate was identified as the primary determinant of ejection duration, whereas aortic diastolic pressure and stroke index demonstrated smaller but statistically significant effects.
Structured PICO
PPopulation20 normal young men
OOutcomeDuration of left ventricular ejectionsurrogate
Heart rate is the primary determinant of left ventricular ejection duration in normal young men, with stroke index and aortic diastolic pressure having minor but statistically significant effects.