Supplementary Material for: Tei Index Complements Conventional Echocardiographic Parameters in Diagnostic Workup of Suspected Takotsubo Syndrome

Background: Tei index (TI) is a combined myocardial performance index for overall cardiac function, the sensitivity of which seems to be better than that of systolic and diastolic parameters alone. Evidence for TI in the context of Takotsubo syndrome (TTS) is currently limited, which is why we chose to investigate this parameter in affected patients. Subjects and Methods: Patients with TTS (n = 51), acute coronary syndrome (ACS; n = 29) and controls (n = 58) were retrospectively investigated. Laboratory and echocardiographic parameters including TI were analyzed for their ability to discriminate TTS in the total study cohort. Results: TI was highest, and thus most pathological, in patients with TTS (median 0.516 vs. ACS: 0.355 vs. control: 0.313, p < 0.0001) and showed the best discriminatory ability for TTS (AUC: 0.836, p < 0.0001). A cut-off for diagnosis of TTS was calculated at ≥0.418 (specificity: 83.5%, sensitivity: 74.0%) by means of the Youden index. Conclusion: The discriminatory ability of TI was better than that of other echocardiographic parameters such as LV systolic function. Due to the simple, fast and inexpensive way of calculating TI, diagnostic workup with conventional parameters could be complemented by Tei index in patients with suspected Takotsubo syndrome.