Discussion

We identified two important clinical findings in this case. First, serial electrocardiographic findings and speckle-tracking echocardiographic changes in the paediatric case of takotsubo cardiomyopathy with single right ventricle is similar to those in adults. Second, seizures can induce takotsubo cardiomyopathy in children.

Takotsubo cardiomyopathy is rare in children, ^{Reference Rozema and Klein2} particularly in those with a single ventricle. ^{Reference Derk, Aboulhosn and Reardon3,Reference Watanabe, Shiraishi, Takahashi and Tsuchida4} Previous paediatric reports did not detail serial electrocardiographic findings and speckle-tracking echocardiographic changes. ^{Reference Rozema and Klein2–Reference Watanabe, Shiraishi, Takahashi and Tsuchida4} A previous adult study ^{Reference Mitsuma, Kodama and Ito5} showed serial findings in women with takotsubo cardiomyopathy and reported that the clinical course comprised four electrocardiographic phases, with phase 1 characterised by ST-segment elevation immediately after onset. T-wave inversion was observed on days 1–3 (phase 2), and inverted T-waves improved transiently on days 2–6 (phase 3). Subsequently, giant inverted T-waves appeared and persisted for more than 2 months (phase 4). Finally, all electrocardiographic abnormalities normalised over several months. Similarly, the present case showed ST-segment elevation in leads V2 to 6 after onset and T-wave inversion 2 days later. On day 5, T-wave normalisation occurred, and giant T-wave inversion was observed on day 8. Gradually, negative T-waves normalised by day 40. Echocardiographic findings showed similar changes. Immediately after onset, the right ventricle-fractional area change was 16.8% (30.8% before onset) and the global longitudinal strain was −3.8%, which gradually improved to 31.0% and −10.3%, respectively, when the electrocardiogram showed giant negative T-waves on day 8. In adults, left ventricular strain has been reported to improve before the systolic function, while right ventricular strain improves simultaneously with systolic function, ^{Reference Tibrewala, Freed and Akhter6} suggesting that takotsubo cardiomyopathy with single right ventricle disease follows the same course as takotsubo cardiomyopathy in the right ventricle.

The triggers for takotsubo cardiomyopathy in adults and children are almost the same: psychological stress in 52% and physical stress in 48% (comprising acute respiratory failure in 26%, central nervous system disease in 18%, and malignant disease in 11%). ^{Reference Sharkey, Windenburg and Lesser7} In adults ^{Reference Stöllberger, Wegner and Finsterer8} and children, ^{Reference Yamaguchi, Nagase and Yoshida9} seizures inducing takotsubo cardiomyopathy have been noted. According to the latter report, takotsubo cardiomyopathy occurred within 72 hours after seizure, and in the present case, the disease onset was 36 hours after seizure. In the present case, it is thought that the severe seizure caused physical stress, leading to the onset of takotsubo cardiomyopathy. However, the previous physician did not evaluate cardiac function, and the exact mechanism of onset was unclear because the tachycardia that occurred after the severe seizure may have triggered takotsubo cardiomyopathy. In any case, seizures in patients with single ventricular disease can lead to takotsubo cardiomyopathy; therefore, epilepsy should be strictly controlled.

There is no specific treatment for takotsubo cardiomyopathy, and unnecessary inotropic drugs should be avoided because its pathogenesis is associated with excessive sympathetic nervous system activity. ^{Reference Paur, Wright and Sikkel10} Excessive sympathetic nervous system activity is thought to be the main pathogenesis because there are more β2-adrenergic receptors in the apex than in the base of the heart, and more sympathetic nerve endings are distributed in the basal segment. Accordingly, sympathetic overactivity suppresses the signal switch mechanism, causing contractile dysfunction in the apex, while sympathetic stimulation causes hypercontraction in the base segment. In the present case, catecholamines were used because of the marked decrease in cardiac contraction at disease onset; however, the clinical course and echocardiographic findings strongly suggested takotsubo cardiomyopathy; therefore, early termination of treatment was possible.

In conclusion, serial electrocardiogram findings in a paediatric single right ventricle can be the same as in adult takotsubo cardiomyopathy. To our knowledge, this is the first report to show serial electrocardiogram and two-dimensional speckle tracking changes in a child with single-ventricle disease and takotsubo cardiomyopathy.