HEART-RATE-VARIABILITY BEFORE AND AFTER TREATMENT WITH ELECTROCONVULSIVE-THERAPY

It has been suggested that depression may be associated with decreased parasympathetic activity. Based on this work, we tested the hypothesi s that treatment of depression with electroconvulsive therapy (ECT) wo uld result in a relative increase in cardiac vagal (parasympathetic) a ctivity. Changes in respiratory sinus arrhythmia, a marker of cardiac parasympathetic activity, were examined in nine patients with depressi ve episodes before and after ECT using spectral analysis. Hamilton Dep ression Raring Scale scores decreased significantly. In terms of the h eart rate measures, RR interval tended to decrease and the amplitude o f respiratory sinus arrhythmia decreased significantly following the c ourse of ECT. This reduction in respiratory sinus arrhythmia contribut ed to the overall decrease in RR interval variability. Additionally, t he magnitude of symptom improvement as measured by the Hamilton Scale correlated with the decrease in amplitude of the respiratory sinus arr hythmia. We report that treatment of depression with ECT was associate d with a relative decrease in parasympathetic activity, in contrast to our initial hypothesis of a relative increase. This finding may not b e related to the ECT per se but rather to the resolution of depression , as there was a significant correlation between the decrease in Hamil ton Depression Rating Scale scores and decrease in parasympathetic act ivity. Further work is necessary to better understand the autonomic ch anges associated with depressive illness and the clinical risks and be nefits associated with various treatment modalities. (C) 1997 Elsevier Science B.V.