Rare Etiological Causes of Takotsubo Cardiomyopathy

The valuable comments made by Babu et al. are very much appreciated. Babu et al. stress the value of exercise oxygen consumption and oxygen pulse to assess mortality risk.[1,2] Indeed, both CPET parameters were reduced in the presented patient and remained reduced after the start of therapy.[3] Babu et al. hypothesize that the lack of normalization in CPET parameters may have been explained by a short duration (4 months) of therapy. However, during her recent 1 year follow-up evaluation, we observed no further improvements in maximal exercise capacity (from 167 to 162 W), maximal oxygen consumption (from 2.11 to 2.03 l/min), or oxygen pulse (from 12 to 11 ml/beat). It is difficult to determine whether the lack of normalization of CPET parameters translates into a poor prognosis. The prognostic value of changes in CPET parameters after the start of therapy remains unclear. Studies examining the prognostic utility of CPET in pulmonary arterial hypertension (PAH) were performed in a relatively small number of patients,[4] and in these studies, measurements were only done at baseline.