Abstract
Dynamic heart rate changes have often been described in electroconvulsive therapy (ECT). However, the specific timing of these changes has not been reported. To examine the cardiac autonomic nervous changed by ECT, we evaluated heart rate and spectral analysis of heart rate variability (HRV) during ECT. Four patients with depression and four patients with schizophrenia who all underwent ECT were included. All ECT sessions were assessed using electrocardiograms (ECG). Heart rate was recorded and analyzed for the HRV indices, HF (an index of parasympathetic activity) and LF/HF (an index of sympathetic activity) during 4 minutes before and after seizure onset. Averaged heart rates over three heart beats pre-seizure and post-seizure onset were compared. Averages of HRV power in the range of 30–100 and 100–170 seconds following a seizure were assessed. Patients showed a significant prolongation of the average over three heart rates just after a seizure, suggesting parasympathetic dominance at this first phase. The average power of LF/HF significantly increased in the latency of 30–100 seconds after a seizure, while the average power of HF significantly increased in the window of 100–170 seconds after a seizure, reflecting sympathetic activation in the second phase and parasympathetic activation in the third phase. The evaluation of heart rates and HRV revealed a triphasic change from parasympathetic to sympathetic to parasympathetic cardiac autonomic activity following a seizure.
