Takotsubo syndrome (TTS) is a poorly recognized heart disease that was initially regarded as a benign condition. Recently, it has been shown that TTS may be associated with severe clinical complications including death and that its prevalence is probably underestimated. Since current guidelines on TTS are lacking, it appears timely and important to provide an expert consensus statement on TTS. The clinical expert consensus document part I summarizes the current state of knowledge on clinical presentation and characteristics of TTS and agrees on controversies surrounding TTS such as nomenclature, different TTS types, role of coronary artery disease, and etiology. This consensus also proposes new diagnostic criteria based on current knowledge to improve diagnostic accuracy.

The clinical expert consensus statement on takotsubo syndrome (TTS) part II focuses on the diagnostic workup, outcome, and management. The recommendations are based on interpretation of the limited clinical trial data currently available and experience of international TTS experts. It summarizes the diagnostic approach, which may facilitate correct and timely diagnosis. Furthermore, the document covers areas where controversies still exist in risk stratification and management of TTS. Based on available data the document provides recommendations on optimal care of such patients for practising physicians.

Takotsubo cardiomyopathy (TTC) remains a potentially life-threatening disease, which is clinically indistinguishable from acute myocardial infarction (MI). Today, no established biomarkers are available for the early diagnosis of TTC and differentiation from MI. MicroRNAs (miRNAs/miRs) emerge as promising sensitive and specific biomarkers for cardiovascular disease. Thus, we sought to identify circulating miRNAs suitable for diagnosis of acute TTC and for distinguishing TTC from acute MI. After miRNA profiling, eight miRNAs were selected for verification by real-time quantitative reverse transcription polymerase chain reaction in patients with TTC (n = 36), ST-segment elevation acute myocardial infarction (STEMI, n = 27), and healthy controls (n = 28). We quantitatively confirmed up-regulation of miR-16 and miR-26a in patients with TTC compared with healthy subjects (both, P < 0.001), and up-regulation of miR-16, miR-26a, and let-7f compared with STEMI patients (P < 0.0001, P < 0.05, and P < 0.05, respectively). Consistent with previous publications, cardiac specific miR-1 and miR-133a were up-regulated in STEMI patients compared with healthy controls (both, P < 0.0001). Moreover, miR-133a was substantially increased in patients with STEMI compared with TTC (P < 0.05). A unique signature comprising miR-1, miR-16, miR-26a, and miR-133a differentiated TTC from healthy subjects [area under the curve (AUC) 0.835, 95% CI 0.733–0.937, P < 0.0001] and from STEMI patients (AUC 0.881, 95% CI 0.793–0.968, P < 0.0001). This signature yielded a sensitivity of 74.19% and a specificity of 78.57% for TTC vs. healthy subjects, and a sensitivity of 96.77% and a specificity of 70.37% for TTC vs. STEMI patients. Additionally, we noticed a decrease of the endothelin-1 (ET-1)-regulating miRNA-125a-5p in parallel with a robust increase of ET-1 plasma levels in TTC compared with healthy subjects (P < 0.05). The present study for the first time describes a signature of four circulating miRNAs as a robust biomarker to distinguish TTC from STEMI patients. The significant up-regulation of these stress- and depression-related miRNAs suggests a close connection of TTC with neuropsychiatric disorders. Moreover, decreased levels of miRNA125a-5p as well as increased plasma levels of its target ET-1 are in line with the microvascular spasm hypothesis of the TTC pathomechanism.

Takotsubo syndrome (TTS), also known as broken heart syndrome or stress cardiomyopathy, was first described in 1990¹ as transient apical ballooning of the left ventricle in the absence of obstructive coronary artery disease, predominantly present in female patients.² However, variants of this syndrome with midventricular,^3-6 basal,^7-11 and focal^12,13 wall motion patterns were later described. Interestingly, different forms of TTS can also occur in the same patient.¹⁴

Aims Clinical presentation of takotsubo syndrome (TTS) mimics acute coronary syndrome (ACS) and does not allow differentiation. We aimed to develop a clinical score to estimate the probability of TTS and to distinguish TTS from ACS in the acute stage. Methods and results Patients with TTS were recruited from the International Takotsubo Registry ( www.takotsubo‐registry.com) and ACS patients from the leading hospital in Zurich. A multiple logistic regression for the presence of TTS was performed in a derivation cohort (TTS, n = 218; ACS, n = 436). The best model was selected and formed a score (InterTAK Diagnostic Score) with seven variables, and each was assigned a score value: female sex 25, emotional trigger 24, physical trigger 13, absence of ST‐segment depression (except in lead aVR) 12, psychiatric disorders 11, neurologic disorders 9, and QTc prolongation 6 points. The area under the curve (AUC) for the resulting score was 0.971 [95% confidence interval (CI) 0.96–0.98] and using a cut‐off value of 40 score points, sensitivity was 89% and specificity 91%. When patients with a score of ≥50 were diagnosed as TTS, nearly 95% of TTS patients were correctly diagnosed. When patients with a score ≤31 were diagnosed as ACS, ∼95% of ACS patients were diagnosed correctly. The score was subsequently validated in an independent validation cohort (TTS, n = 173; ACS, n = 226), resulting in a score AUC of 0.901 (95% CI 0.87–0.93). Conclusion The InterTAK Diagnostic Score estimates the probability of the presence of TTS and is able to distinguish TTS from ACS with a high sensitivity and specificity. Trial registration: NCT0194762