Ten psychotic and 10 normal children, paired for age and sex, were compared for respiratory sinus arrhythmia differences under conditions of spontaneous and 5, 10, and 15 sec interval breathing. Cardiac rate and respiratory changes were simultaneously recorded. Parameters of degree of change and timing for each respiratory-cardiac cycle and its associated changes in heart rate were measured and compared statistically. Results show significant differences between psychotics and normal controls as follows:
- 1The psychotics did not sustain the acceleratory phase of the cardiac cycle as did the controls.
- 2The lag intervals (interval between onset of inspiration and onset of cardiac acceleration, interval between onset of expiration and onset of cardiac deceleration) were more consistent for the normal controls than for the psychotics.
- 3At maximum respiratory depths the psychotics no longer demonstrated a direct relationship between depth of respiration and degree of cardiac rate change as did the controls.
We conclude that there is a different or less well-coordinated combination of operative forces in the sinus arrhythmia mechanism of the psychotics as compared to the controls.