Usefulness of Sum of ST-Segment Elevation on Electrocardiograms (Limb Leads) for Predicting In-Hospital Complications in Patients With Stress (Takotsubo) Cardiomyopathy

Abstract

Although the prognosis of patients with stress (takotsubo) cardiomyopathy is relatively favorable, serious complications occur in some patients. It is generally accepted that electrocardiography is an essential tool for the diagnosis of stress cardiomyopathy, with findings highly suggestive of the characteristics of myocardial damage. We tested the hypothesis that the quantitative analysis of electrocardiograhic changes can predict complications in stress cardiomyopathy. The study subjects were 85 patients with stress cardiomyopathy. A total of 34 patients developed ≥1 in-hospital complications (heart failure, intraventricular pressure gradient [>30 mm Hg], cardiogenic shock, ventricular tachycardia/fibrillation, and embolism). Patients with complications were likely to have a higher heart rate (96 ± 25 vs 76 ± 17 beats/min, p <0.001), larger sum of ST-segment elevation in 12 leads (median 10.5 mm; interquartile range 5.0 to 17.5 vs 3.0 mm, interquartile range 0 to 7.0; p <0.001) and extension of ST-segment elevation to limb leads (50% vs 12%, p <0.001) than those without complications. Multivariate logistic regression analysis identified heart rate (odds ratio 1.05, 95% confidence interval 1.02 to 1.07, p = 0.001) and sum of ST-segment elevation in 12 leads (odds ratio 1.24, 95% confidence interval 1.11 to 1.39, p <0.001) as significant and independent predictors of complications. Receiver operating characteristic analysis selected 5.5 mm as the best cutoff value of sum of ST-segment elevation in 12 leads for the prediction of complications, with a sensitivity and specificity of 74% and 73%, respectively, and area under the curve of 0.81 (95% confidence interval 0.72 to 0.90, p <0.001). The results suggest that the extent and magnitude of ST-segment elevation on the electrocardiogram are potentially useful predictors of in-hospital complications in patients with stress cardiomyopathy.