We appreciate the interest and comments of Khalid et al. regarding our article.1 The results of the successive registries and experimental studies add evidence to support that estrogens play an important role in the modulation of catecholaminergic discharge on the heart, thus affecting the development and outcome of tako-tsubo syndrome (TTS). It is interesting to think that this could lead in the future to design strategies for targeted treatment in patients with TTS. However, other sex-related factors probably influence this different prognosis. For instance, the number of previous pregnancies has recently been shown to be associated with a better prognosis in women with heart failure.2 Also, important sex-related differences have been described in patients with acute myocardial infarction.3 Irrespective of these considerations, we agree that, with respect to the prognosis of patients with TTS, the underlying trigger is also an important factor. In fact, in a previous work by our group,4 we reported that the clinical course during hospitalization (length of stay and complications) and follow-up (recurrences) was worse in secondary than in primary TTS. This is why we proposed to extend this simple nomenclature. Primary TTS has no identifiable trigger, or is triggered by major psychological stress, while secondary TTS is triggered by physical factors (such as respiratory exacerbation, surgery, and trauma).5
The authors wish to acknowledge the inestimable and generous contribution of Irene Martín and all the RETAKO investigators.