Differences in ST-elevation and T-wave amplitudes do not reliably differentiate takotsubo cardiomyopathy from acute anterior myocardial infarction.

Previous efforts to distinguish acute anterior ST-elevation myocardial infarction (anterior-STEMI) from various forms of takotsubo cardiomyopathy (TTC) by electrocardiography (ECG) have produced differing results. We performed a retrospective comparison of acute ECGs between 48 apical and 9 mid-ventricular TTC patients, with 96 anterior-STEMI patients. ECG was recorded in acute phase (<24h from onset of pain), and analyzed for ST-changes, negative T-waves, abnormal Q-waves and QT-interval duration. Time from onset of pain to ECG was gathered from patient records. Anterior-STEMI patients had ST-elevation in lead V1 more frequently than apical (70% vs 15%, p<0.0001) or mid-ventricular TTC patients (70% vs 0%, p<0.0001), and higher ST-elevation amplitudes in leads V2-V5 (p<0.02). Lack of ST-elevation in lead V1 and ST-elevation amplitude <2mm in lead V2 distinguished TTC from anterior-STEMI patients with 63% sensitivity and 93% specificity, with 79% predictive value. In patients with anterior ST-elevation and acute chest pain, lack of ST-elevation in lead V1 and ST-elevation amplitude <2mm in lead V2 suggests a TTC diagnosis. However, this criterion is not reliable enough in clinical practice to distinguish between TTC and anterior-STEMI patients.

Parkkonen O ，Allonen J ，Vaara S ，Viitasalo M ，Nieminen MS ，Sinisalo J ... -  《-》

Is it possible to differentiate between Takotsubo cardiomyopathy and acute anterior ST-elevation myocardial infarction?

Several studies have investigated the ability of the twelve-lead electrocardiogram (ECG) to reliably distinguish Takotsubo cardiomyopathy (TC) from an acute anterior ST-segment elevation myocardial infarction (STEMI). In these studies, only ECG changes were required - ST-segment deviation and/or T-wave inversion - in TC whereas in acute anterior STEMI, ECGs had to meet STEMI criteria. In the majority of these studies, patients of both genders were used even though TC predominantly occurs in women. The aim of this study is to see whether TC can be distinguished from acute anterior STEMI in a predominantly female study population where all patients meet STEMI-criteria. Retrospective analysis of the ST-segment changes was done on the triage ECGs of 37 patients with TC (34 female) and was compared to the triage ECGs of 103 female patients with acute anterior STEMI. The latter group was divided into the following subgroups: 46 patients with proximal, 47 with mid and 10 with distal LAD occlusion. Three ST-segment based ECG features were investigated: (1) Existing criterion for differentiating anterior STEMI from TC: ST-segment depression >0.5mm in lead aVR+ST-segment elevation ≤1mm in lead V1, (2) frontal plane ST-vector and (3) mean amplitude of ST-segment deviation in each lead. The existing ECG criterion was less accurate (76%) than in the original study (95%), with a large difference in sensitivity (26% vs. 91%). Only a frontal plane ST-vector of 60° could significantly distinguish TC from all acute anterior STEMI subgroups (p<0.01) with an overall diagnostic accuracy of 81%. The mean amplitude in inferior leads II and aVF was significantly higher for patients with TC compared to all patients with acute anterior STEMI (p<0.01 and p<0.05 respectively) and the mean amplitude in the precordial leads V1 and V2 was significantly lower compared to proximal and mid LAD occlusion (p<0.01). Given the consequences of missing the diagnosis of an acute anterior STEMI the diagnostic accuracy of the ECG criteria investigated in this retrospective study were insufficient to reliably distinguish patients with TC from patients with an acute anterior STEMI. To definitely exclude the diagnosis of an acute anterior STEMI coronary angiography, which remains the gold standard, will need to be performed.

Vervaat FE ，Christensen TE ，Smeijers L ，Holmvang L ，Hasbak P ，Szabó BM ，Widdershoven JW ，Wagner GS ，Bang LE ，Gorgels AP ... -  《-》

Electrocardiographic differentiation of early repolarization from subtle anterior ST-segment elevation myocardial infarction.

Anterior ST-segment elevation myocardial infarction (STEMI) can be difficult to differentiate from early repolarization on the ECG. We hypothesize that, in addition to ST-segment elevation, T-wave amplitude to R-wave amplitude ratio (T-wave amplitude(avg)/R-wave amplitude(avg)), and R-wave amplitude in leads V2 to V4, computerized corrected QT interval (QTc) and upward concavity would help to differentiate the 2. We seek to determine which ECG measurements best distinguish STEMI versus early repolarization. This was a retrospective study of patients with anterior STEMI (2003 to 2009) and early repolarization (2003 to 2005) at 2 urban hospitals, one of which (Minneapolis Heart Institute) receives 500 STEMI patients per year. We compared the ECGs of nonobvious ("subtle") anterior STEMI with emergency department noncardiac chest pain patients with early repolarization. ST-segment elevation at the J point and 60 ms after the J point, T-wave amplitude, R-wave amplitude, QTc, upward concavity, J-wave notching, and T waves in V1 and V6 were measured. Multivariate logistic regression modeling was used to identify ECG measurements independently predictive of STEMI versus early repolarization in a derivation group and was subsequently validated in a separate group. Of 355 anterior STEMIs identified, 143 were nonobvious, or subtle, compared with 171 early repolarization ECGs. ST-segment elevation was greater, R-wave amplitude lower, and T-wave amplitude(avg)/R-wave amplitude(avg) higher in leads V2 to V4 with STEMI versus early repolarization. Computerized QTc was also significantly longer with STEMI versus early repolarization. T-wave amplitude did not differ significantly between the groups, such that the T-wave amplitude(avg)/R-wave amplitude(avg) difference was entirely due to the difference in R-wave amplitude. An ECG criterion based on 3 measurements (R-wave amplitude in lead V4, ST-segment elevation 60 ms after J-point in lead V3, and QTc) was derived and validated for differentiating STEMI versus early repolarization, such that if the value of the equation ([1.196 x ST-segment elevation 60 ms after the J point in lead V3 in mm]+[0.059 x QTc in ms]-[0.326 x R-wave amplitude in lead V4 in mm]) is greater than 23.4 predicted STEMI and if less than or equal to 23.4, it predicted early repolarization in both groups, with overall sensitivity, specificity, and accuracy of 86% (95% confidence interval [CI] 79, 91), 91% (95% CI 85, 95), and 88% (95% CI 84, 92), respectively, with positive likelihood ratio 9.2 (95% CI 8.5 to 10) and negative likelihood ratio 0.1 (95% CI 0.08 to 0.3). Upward concavity, upright T wave in V1 or T wave, in V1 greater than T wave in V6, and J-wave notching did not provide important information. R-wave amplitude is lower, ST-segment elevation greater, and QTc longer for subtle anterior STEMI versus early repolarization. In combination with other clinical data, this derived and validated ECG equation could be an important adjunct in the diagnosis of anterior STEMI.

Smith SW ，Khalil A ，Henry TD ，Rosas M ，Chang RJ ，Heller K ，Scharrer E ，Ghorashi M ，Pearce LA ... -  《-》

Acute electrocardiographic differences between Takotsubo cardiomyopathy and anterior ST elevation myocardial infarction.

The aim of this study was to compare ECG findings between anterior ST elevation myocardial infarction (STEMI) and Takotsubo cardiomyopathy (TC) in a similar sample of postmenopausal women. Between 2008 and 2011, 27 patients with TC were retrospectively enrolled and matched with 27 STEMI patients with the same age and sex taken from the prospective database of our laboratory. The absence of abnormal Q waves, the ST depression in aVR and the lack of ST elevation in V1 were significantly associated with TC (respectively: 52% vs 18%, p=0.01; 47% vs 11%, p=0.01; 80% vs 41%, p=0.01). The combination of these ECG findings identified TC with a specificity of 95% and a positive predictive value of 85.7%. The ECG on admission may be useful to distinguish TC from anterior STEMI. The combination of three ECG findings identifies patients with TC with high specificity and positive predictive value.

Mugnai G ，Pasqualin G ，Benfari G ，Bertagnolli L ，Mugnai F ，Vassanelli F ，Marchese G ，Pesarini G ，Menegatti G ... -  《-》

Performance of electrocardiographic criteria to differentiate Takotsubo cardiomyopathy from acute anterior ST elevation myocardial infarction.

The initial electrocardiogram (ECG) in Takotsubo cardiomyopathy (TC) can mimic an acute, anterior ST-segment elevation myocardial infarction (STEMI). Given the profound and immediate treatment differences between TC and STEMI, it would be clinically valuable to distinguish them using ECG criteria. Presenting ECGs for proven cases of TC and acute, anterior STEMI were retrospectively collected. QRS onset and J-point were manually identified using custom software to compute median ST deviation for each lead. Six published ECG criteria were examined for diagnostic accuracy using the clinical diagnosis as the gold standard. 33 TC and 263 acute, anterior STEMI cases were identified. ST-segment deviation differed significantly between groups for all leads except aVR, I, V5, and V6. All six published ECG criteria showed a marked reduction in diagnostic accuracy in our validation cohort, except for a combination of ST-elevation in leads V2<1.75 mm and V3<2.5 mm (sensitivity 79%, specificity 73% for TC). Our study demonstrates the limited diagnostic accuracy of published ECG rules to distinguish TC from acute, anterior STEMI. Given the rarity of TC and the clinical consequences of a "false positive" TC diagnosis based on ECG criteria alone, such rules should not be used in practice. TC remains a diagnosis of exclusion after emergent angiography in patients with an acute coronary syndrome and significant ST-segment elevation.

Johnson NP ，Chavez JF ，Mosley WJ 2nd ，Flaherty JD ，Fox JM ... -  《-》