We report the case of an 18-year-old woman with Down syndrome (DS) who developed Takotsubo cardiomyopathy (TSC) immediately after the administration of electroconvulsive therapy (ECT), a treatment prescribed for Down syndrome regression disorder resistant to oral psychotropic drugs. TSC is a nonischemic cardiomyopathy related to psychological or physical stress, which has been described as a rare complication of ECT (Kinoshita et al., 2023, Journal of Electroconvulsive Therapy, 39, 185-192). The clinical description of the case is accompanied by a discussion of the peculiarities of the autonomic nervous system in DS.