ID 25 – Changes of cardiac autonomic nervous activity during a course of electroconvulsive therapy in depression

Abstract

Objective Seizure duration has been reported to decrease across a course of electroconvulsive therapy (ECT) (anticonvulsant effect). Because dynamic autonomic activity changes have been described during ECT, and are affected by seizure generalization, we examined the relationship between longitudinal autonomic nervous activity changes on a course of ECT and seizure duration. Methods Electroencephalograms (EEG) and electrocardiograms (ECG) of twelve depressive patients were recorded during ECT procedures. The mean heart rate (HR) in 30 s prior to stimulus onset was defined as baseline HR. The T Max peak was designated as the data point with the maximum HR after stimulus onset. T 1/2 points were determined as the time point when HR was reduced midway between baseline HR and T Max HR. The changes of EEG seizure duration, T Max , and T 1/2 throughout the course of ECT, and their correlations, were examined. Results T 1/2 significantly decreased with repetition of ECT. T 1/2 was positively correlated to EEG seizure duration. Conclusions The time to return to the baseline from sympathetic nervous activation caused by ECT stimulation is shortened during a course of ECT. Key message Sympathetic nervous activity suppression and an anticonvulsant effect may contribute to the clinical action of ECT.