Abstract 10406: The Development of Negative T Waves After Initial ST-Segment Elevation Differs Between Takotsubo Cardiomyopathy and Reperfused Anterior Acute Myocardial Infarction
In takotsubo cardiomyopathy (TC), negative T waves (Neg T) with QT interval prolongation commonly appear after resolution of ST-segment elevation (ST↑) in precordial leads, but also occur in reperfused anterior acute myocardial infarction (AMI). These ECG findings are considered to be associated with viable but sympathetically denervated myocardium. To clarify ECG characteristics of TC, we compared ECGs on admission and those with the greatest amplitude of subsequent Neg T (mean 2 days later) between 33 patients with TC and 346 with a first reperfused anterior AMI. All patients were admitted within 6 h after the onset. As compared with patients with anterior AMI, those with TC were older (70±11 vs 61±11 years, p<0.01), more likely to be women (85% vs 15%, p<0.01) and had a lower peak creatine kinase (409±533 vs 3682±2622 mU/ml, p<0.01) despite a lower admission left ventricular ejection fraction (39±14% vs 46±10%, p=0.08). TC was associated with a smaller maximal ST↑ on admission (4.5±4.9 vs 7.0±3.0 mm, p<0.01), more frequent absence of abnormal Q waves (79% vs 9%, p<0.01), a greater maximal amplitude of Neg T (9.1±5.1 vs 6.6±4.2 mm, p<0.01) and a longer maximal QTc interval (641±94 vs 587±84 ms, p<0.01) in subacute phase. Distribution of ST↑ (>0.5 mm in limb leads, >1.0 mm in precordial leads) and Neg T (>1.0 mm) was shown in Figure, in which the anatomically contiguous Cabrera sequence was used to display limb leads. The distributions of ST↑ differed between TC and anterior AMI. In anterior AMI, the distributions and the prevalences of ST↑ and of Neg T were similar. In TC, however, Neg T were more broadly distributed and the prevalences of Neg T were higher as compared with ST↑. In conclusion, the development of Neg T after initial ST↑ differs between TC and reperfused anterior AMI, suggesting the differences in underlying electrophysiologic mechanisms between the 2 diseases. TC might be associated with more extensive viable but sympathetically denervated myocardium.
- © 2010 by American Heart Association, Inc.