Clinical correlates and prognostic significance of electrocardiographic abnormalities in apical ballooning syndrome (Takotsubo/stress-induced cardiomyopathy)

Abstract

Apical ballooning syndrome (ABS) is a unique transient cardiomyopathy that mimics an acute myocardial infarction. The relative frequency of ST-segment elevation on the 12-lead electrocardiogram (ECG) and its prognostic significance is unknown. The aims of this study were to evaluate the frequency and the clinical correlates of ST- and T-wave abnormalities on the admission ECG in patients with ABS. Patients were retrospectively identified from the cardiac catheterization database--those who underwent coronary and left ventricular angiography and fulfilled the Mayo criteria for ABS during the period January 1988 to November 2006. They were divided into 3 groups according to the presence of (1) ST-segment elevation (>1 mm in 2 contiguous lead) or new left bundle branch block, (2) T-wave inversion (>3 mm in 3 contiguous leads) but no ST shift, and (3) nonspecific ST-T abnormalities or normal ECG at the time of admission. Clinical and echocardiographic findings were compared between groups. Among the 105 patients, 36 (34.2%), 32 (30.4%), and 37 (35.2%) patients were in the three respective groups. There were no differences in the clinical characteristics, ejection fraction, and outcomes between the 3 groups. Over a median follow-up of 2.5 years, there was no difference in the 5-year recurrence rate of ABS between the 3 groups (13%, 5%, 17% patients, respectively, P = .25). The 5-year mortality was similar in the 3 groups (24%, 7.3%, 10.8%, P = .58). ST-segment elevation is absent in two thirds of patients with ABS. Thus, the cardiomyopathy may mimic either ST-elevation or non-ST-elevation myocardial infarction. The ECG abnormalities at presentation do not correlate with the magnitude of ventricular dysfunction or outcomes.