Validation of the InterTAK Diagnostic Score for Differentiating Takotsubo Syndrome from Acute Coronary Syndrome in a Middle Eastern Population.

Background/Objectives: Takotsubo syndrome (TS) is an acute, reversible cardiac condition that represents an increasingly recognized acute heart failure syndrome affecting 2-3% of patients presenting with suspected acute coronary syndrome (ACS), with significant morbidity and mortality comparable to myocardial infarction. The InterTAK Diagnostic Score was developed to differentiate TS from ACS at initial presentation. However, its performance characteristics and optimal cutoff values in Middle Eastern populations have not been established, despite potential ethnic and cultural variations in the clinical presentation and trigger patterns. Methods: We conducted a retrospective, case-control, diagnostic accuracy study of patients admitted to Tawam Hospital, Al Ain, United Arab Emirates, between June 2012 and June 2022. Power analysis indicated 80% power to detect an AUC difference of 0.15 with our sample size. Results: Eleven patients with confirmed TS (mean age 53.4 ± 14.1 years, 72.7% female) were compared with 26 age-matched patients with ACS (mean age 54.6 ± 11.0 years, 23.1% female). TS diagnosis was based on modified Mayo Clinic criteria with independent adjudication by two cardiologists (κ = 0.92). The InterTAK score was calculated for each patient based on seven clinical variables. The mean InterTAK score was significantly higher in TS patients (49.1 ± 14.8) compared with ACS patients (13.0 ± 9.3; p < 0.001). The receiver operating characteristic curve analysis yielded an area under the curve (AUC) of 0.974 (95% confidence interval, 0.92-1.00), exceeding the original validation cohort's performance (AUC 0.971). An InterTAK score ≥ 40 identified TS with 81.8% sensitivity and 100% specificity. Remarkably, when the cutoff was lowered to ≥36, sensitivity improved to 90.9% while maintaining 100% specificity. Conclusions: The InterTAK Diagnostic Score demonstrated exceptional discriminatory ability (AUC 0.974, 95% CI 0.92-1.00) in differentiating TS from ACS in our Middle Eastern cohort, surpassing the original validation study's performance. A regionally optimized cutoff of ≥36 points achieved 90.9% sensitivity with 100% specificity, compared to the original ≥40 cutoff (81.8% sensitivity, 100% specificity). These findings establish the score's trans-ethnic validity while highlighting the importance of regional calibration. Larger prospective studies are warranted to validate these findings and establish region-specific cutoff values.