Efficiency of the Stimulus Characteristics of ECT

OBJECTIVE: Greater ECT stimulus efficiency allows for a lower stimulus dose and should diminish the side effects of ECT. METHOD: Four different ECT stimuli of identical charge (average mC=2.5 times age) with pulse widths of 0.5 msec and 1 msec and frequencies of 30 Hz and 60 Hz, respectively, were compared for efficiency. The stimuli were applied in a balanced order to each of 24 subjects. Asymmetric bilateral electrode placement was used. RESULTS: Peak heart rates were higher with the 0.5-msec pulse width than the 1-msec pulse width. Seizure induction was more successful with the 0.5-msec pulse width than the 1-msec pulse width. Stimulus frequency had no effect on heart rate or seizure induction. CONCLUSIONS: The pulse width of 0.5 msec is more efficient than the 1-msec pulse width. The "half-age" dose for the first bilateral ECT treatment is usually successful for subsequent ECTs when the 0.5-msec pulse width is used.