How does left ventricular function change during graded supine exercise as assessed by two-minute equilibrium gated blood pool scanning in normal subjects?
Two-minute equilibrium gated blood pool scanning demonstrates that normal subjects increase their left ventricular ejection fraction during exercise primarily through a reduction in end-systolic volume.
In 20 normal volunteers, two minute equilibrium gated blood pool scanning (GBPS) was used to assess left ventricular function during rest and three stages of graded supine exercise on a bicycle ergometer. The three work loads were individualised for each subject from a previously performed exercise test and corresponded to mild, moderate and severe stress. The short imaging time was validated against standard GBPS. With exercise all subjects increased their left ventricular ejection fraction and in the majority, most of this rise occurred with the lowest work load. This change was predominantly due to a marked fall in end-systolic volume. The end-diastolic volume initially fell, then at peak exercise returned to baseline values. The major change in stroke volume occurred at peak exercise.
Kalff et al. (Wed,) studied this question.