IJCS | Volume 33, Nº1, January / February 2019

95 Costa et al. Takotsubo syndrome versus transmural acute myocardial infarction Int J Cardiovasc Sci. 2020;33(1):94-97 Brief Communication Inclusion criteria Patients with ST-elevation and suspicion of ACS at admission, who were subsequently diagnosed with TTS according to Mayo Clinic criteria, 5 were included in the case group. Patients with ST-elevation and suspicion of ACS at admission, whowere subsequentlydiagnosedwith STEMI according to the Universal Definition of Myocardial Infarction, 6 were included in the control group. Exclusion criteria Patients with a previous diagnosis of heart failure, those without coronary angiography, and patients with cardiorespiratory arrest at admission were excluded from the study. Statistical analysis Normally distributed continuous variables are described as mean ± standard deviation (SD), and non- normally distributed continuous variables are expressed as median and interquartile range (IQR). Categorical variables are presented as percentages. The Student’s t-test (parametric) or the Mann–Whitney test (non- parametric) was used for comparison of continuous variables. Categorical variables were compared using Pearson’s chi-square test and or the Fisher’s exact test when appropriate. A value of p < 0.05 was considered to denote statistical significance. Ethical aspects The project was approved by the Research Ethics Committee of Santa Izabel Hospital (CAAE no. 76922117.0.0000.5520). Written informed consent was not required given the retrospective nature of the study. Results We evaluated 183 cases of suspected STEMI, six (3.2%) of them diagnosed with TTS. Comparison of demographic and clinical variables between cases and controls is shown in Table 1. TTS patients had a higher frequency of previous emotional stress (50.0 vs. 12.5%; p = 0.04), higher prevalence of depressive disorders (50.0 vs. 12.5%; p = 0.04), lower peak troponin levels (2.20 vs. 9.43 ng/ mL; p = 0.033), lower ejection fraction (35.5 vs. 56.0%; p = 0.018), and longer QTc intervals (516ms vs. 452 ms; p = 0.01) than STEMI patients. Also, TTS patients had significantly higher InterTAK scores (60.5 vs. 24.0; p < 0.001), figure 1. Discussion The data presented in this study, on a population of patients suspected of STEMI in Brazil, are in agreement with the literature and largemultinational registries. 1,2 The prevalence of TTS (3.2%) was higher than that reported in other studies, probably because the study populationwas composed only of suspected cases of STEMI. Most international Takotsubo registries 2,3 have collected data on patients with clinical manifestations of ACS, including STEMI and non–STEMI patients. Our study focused exclusively on patients within the spectrum of STEMI, because the need for a rapid diagnosis and rapid initiation of reperfusion therapy in STEMI cases makes the differential diagnosis from TTS a challenge. Early recognition of TTS can help avoid unnecessary procedures in these patients. Among the variables that differed significantly between cases and controls, we highlight gender, emotional and/or physical stress, neuropsychiatric disorders, and prolonged QTc interval – all of them compose the InterTAK score, a diagnostic tool that estimates the probability of a TTS event, with good sensitivity and specificity. 3 Although each of these characteristics is not specific of TTS, when taken together, they strongly suggest TTS. 2 There was a high prevalence of coronary artery disease (50%) in the TTS group, which was not associatedwith left ventricular dysfunction. This prevalence was higher than that reported in international registries and may be related to the mean age of the case group (72.5 ± 7.2 years). In this age range, some degree of coronary atherosclerosis is expected. A recent expert consensus statement on TTS 7 recommended the use of the InterTAK score only for patients suspected of TTS with non-ST elevation ACS. However, the good performance of the tool in our study suggests that it may also be used in suspected cases of STEMI, as sometimes the coronary pattern alone is not sufficient to differentiate between myocardial infarction with normal coronary arteries, myocarditis, and TTS, even in the absence of coronary obstruction. The limitations of our study include its retrospective nature and the lack of a clinical follow-up. The small