Modulation of the PR Interval after Electroconvulsive Therapy in Depressed Patients with or without Suicide Ideation:...

Depression is a common mental disorder, often accompanied by suicidal ideation (SI). Modified electroconvulsive therapy (MECT) is widely used as an effective treatment for severe depression, especially when pharmacotherapy has failed. However, concerns regarding the potential cardiovascular effects of MECT have prompted further investigation.

A total of 100 patients with depressive disorders undergoing MECT were recruited in this study. Among them, 70 had suicide ideation (SI group) and 30 did not (non-SI group). Electrocardiogram (ECG) recordings were obtained before MECT and on the second day after several sessions of MECT treatment.

After treatment with MECT, no significant differences were observed in ECG parameters, including PR intervals, QT intervals, and heart rates. However, a significant interaction between time and group on PR intervals was observed (F(1,98)=5.5, p=0.02). Specifically, patients in the non-SI group exhibited a slight increase in PR intervals compared with baseline values, whereas those in the SI group showed a slight decrease. More importantly, significant differences were observed between the SI and non-SI groups (Z= 2.3, p=0.02). Further linear regression analysis showed that, after controlling for gender and medication types (antidepressants versus antipsychotics), the presence of suicide ideation was independently associated with changes in PR intervals following MECT treatment (β= 0.20, t= 2.04, p= 0.04).

Our findings suggested a significant interaction between time and group on PR intervals after treatment with MECT in patients.

Considering that the within-group changes did not reach statistical significance, future research with a large sample size is warranted to focus on the differential effects of MECT on ECG indicators in depressed patients with or without suicide ideation.