This report addresses the dilemma of continuing lithium prophylaxis and antidepressant therapy in view of cardiovascular adverse effects under electroconvulsive therapy (ECT) in patients with a long history of recurrent affective disorders. A severely depressed 48-year-old woman who had been treated with lithium for 18 years developed a ventricular tachycardia during ECT. Possible interaction with succinylcholine was taken into account, and rocuronium was used as an alternative muscle relaxant. Electroconvulsive therapy was continued without adverse effects after reduction of lithium and withdrawal from duloxetine. Systemic studies on cardiac adverse effects of serotonin and norepinephrine reuptake inhibitors and serotonin and norepinephrine reuptake inhibitor-lithium combinations during ECT are needed.