Abstract Electroconvulsive therapy (ECT) has been recognized as an effective treatment option in severe major depression and treatment-resistant depression. However, its use has been associated with an initial increase in parasympathetic and subsequently sympathetic tone; this has relevance in the context of patients with arrhythmias or pre-excitation syndromes in which some adverse effects have been reported. We present the case of a young female with treatment-resistant depression and a history of Wolff Parkinson White Syndrome admitted for modified ECT. To date, there is no evidence of the anesthetic management of patients with pre-excitation syndromes who require ECT treatment. Therefore, doubts arose regarding the management prior to the procedure. After performing 12 modified ECT sessions an improvement in depressive symptoms was evidenced without any adverse event.