What triggers Takotsubo in cases without an obvious trigger?

We read with interest the article by Mori et al. about a 64-year-old female with a history of rheumatoid arthritis starting 8 years earlier, who developed Takotsubo syndrome (TTS) 3 days prior to admission for chest pain and dyspnoea (1). No definite trigger for TTS was detected but cardiac magnetic resonance imaging (cMRI) suggested the presence of pericarditis, which was assumed not to have been causative (1). We have the following comments and concerns