Electroconvulsive therapy in a patient with metallic implant

To the Editor

Patients with treatment-resistant depression and metallic facial implants can respond well to electroconvulsive therapy (ECT).

A 54-year-old father of three presented to hospital twice in the context of intense suicidal ideation, with one previous high-lethality suicide attempt. He developed depressive symptoms and took a drug and alcohol overdose, culminating in his pilot admission. Since his discharge, he reported having ruminating thoughts of suicide and felt persistently despondent, despite antidepressant treatment.

He was referred to a community psychiatrist by his general practitioner (GP). Given his poor response to antidepressants, ECT was pursued. The patient had a facial implant 3 years earlier, fixed on the lateral margin of the right orbit and the anterior margin of right maxilla, following a zygoma fracture. Given the position of the metallic plate, he was commenced on Left Unilateral (LUL) Ultrabrief pulse ECT.

After five sessions of LUL ultrabrief pulse ECT, he showed minimal improvement, and changing the electrode placement was considered. Repeat computed tomography (CT) scan showed no damage to surrounding brain tissue and no displacement of the implant. The ECT regime was then changed to bifrontal brief pulse. He continued to have another six sessions with good effect. No cognitive decline was noted throughout treatment – measured using Montreal Cognitive Assessment (MoCA).

A case report and review article done by Mortier et al. (2012) suggested that ECT in patients with intracranial metallic implants is harmless. Theoretically, metal is heated with electric current leading to the injury of the surrounding brain tissue. Therefore, ECT electrodes should be placed as far away as possible from metallic implants. Another suggestion by Mortier et al. is to omit threshold titration to avoid unnecessary current exposure. It is postulated that as the energy required to induce a seizure is low and a lot less than what is required for procedures such as cardioversion, the risk of heating the electrodes is small. The findings above are further supported by a literature review and case report by Amanullah et al. (2012) which had a similar conclusion.

Another reason to place electrodes far from metallic implants is to avoid possible electrical shunting (Glezer et al., 2009). Our patient who had a metallic implant and received ECT had no adverse effects throughout his course of treatment and had no cognitive problems. This reaffirms that ECT is a safe treatment for patients with metallic implants and should be considered if required, with careful consideration of possible risks and benefits.