Letter to the Editor Tako-Tsubo cardiomyopathy: NT-proBNP as a reliable parameter of a favourable prognosis? Holger M. Nef ⁎ , H. Möllmann, C. Troidl, Michael Weber, Christian Hamm, A. Elsässer Kerckhoff Heart Center, Department of Cardiology, Benekestr. 2-8, D-61231 Bad Nauheim, Germany Received 26 October 2006; accepted 22 November 2006 Available online 6 March 2007 Keywords: Tako-Tsubo cardiomyopathy; NT-proBNP; Prognosis We read with great interest the recently published report by Kurisu et al. “Documentation of early improvement of left ventricular function in tako-tsubo cardiomyopathy” [1] dealing with the fact of a rather expeditious recovery of the left ventricular dysfunction. As described by the authors Tako-Tsubo cardiomyopathy (TTC) is clinically character- ized by the finding of a transient wall motion abnormality without obstructive coronary artery disease. This is accom- panied by a mild increase of cardiac enzymes and transient ST elevation [2]. Previous studies could demonstrate a favourable prognosis regarding the improvement of the left ventricular dysfunction. Despite the majority of cases reporting a time course of contractile improvement from 8 to 53 days [3] there are several patients showing a early reconstitution of contractile dysfunction [1,4]. In the mentioned paper the authors concluded that the time to normalization of left ventricular function may be dependent on the degree of this phenomenon and assume that the earlier left ventricular function improves the less complication are likely to occur. However, in a recently published case report we could demonstrate that despite a very early reconstitution of left ventricular function within 48 h the clinical course of these patients was complicated by respiratory insufficiency with need for mechanical ventila- tion and by a third degree atrioventricular block. Therefore, it seems to be unlikely that the time period until recovery is a suitable predictor for potential complications or the clinical outcome. What are reliable parameters indicating a favour- able prognosis of patients presenting with TTC? In a retrospective assessment we investigated ten random- ly chosen patients enrolled from March 2005 to October 2006. Upon admission, and subsequently every 12 h until discharge all patients gave blood samples. Serum concentra- tions of N-terminus pro-brain natriuretic peptide (NT- proBNP) were measured using a one-step enzyme immuno- assay based on electrochemiluminescence technology (Elecsys proBNP STAT, Roche Diagnostics, Germany). The serum levels of NT-proBNP on admission were cor- related to the severity of complications during hospitaliza- tion. The higher serum levels of NT-proBNP were on admission, the more clinical complications were present, i.e. need for mechanical respiration, pulmonary oedema, malign ventricular arrhythmia. The median of NT-proBNP of four patients showing complications was 5200 (IQR 4280–6940) whereas for six patients without subsequent complications a median value of 900 (IQR 560–1310) was documented. The mean time between onset of clinical symptoms and first measuring of NT-proBNP values was 4.9±1.2 h. Patients with complications during hospitalization tended to have a prolonged time period between onset of symptoms and admission. Certainly, the limitation of our investigation is its retro- spective character. Nevertheless, we assume that low serum levels of NT-proBNP on admission could be a predictor for a rather favourable prognosis of patients presenting with TTC. International Journal of Cardiology 124 (2008) 237 – 238 www.elsevier.com/locate/ijcard ⁎ Corresponding author. Tel.: +49 6032 996 2829; fax: +49 6032 996 2827. E-mail address: h.nef@kerckhoff.mpg.de (H.M. Nef). 0167-5273/$ - see front matter © 2007 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.ijcard.2006.11.225