Elsevier

International Journal of Cardiology

Volume 199, 15 November 2015, Pages 132-140
International Journal of Cardiology

Usefulness of ECG to differentiate Takotsubo cardiomyopathy from acute coronary syndrome

https://doi.org/10.1016/j.ijcard.2015.07.046Get rights and content

Abstract

Objective

We aimed to describe the evolution of ECG changes in TC compared with MI, and evaluate ECG features which might help to distinguish between these conditions.

Background

Takotsubo cardiomyopathy (TC) can mimic both ST-elevation (STEMI) and non-ST-elevation myocardial infarction (NSTEMI) but management is different. Several electrocardiographic (ECG) abnormalities have been identified which might help to differentiate TC with and without ST-elevation, from STEMI and NSTEMI, respectively.

Methods

We prospectively identified 100 consecutive patients with TC and 100 MI patients. They were divided into 2 groups according to the presence of ST-segment elevation (STE). Serial ECGs from admission to Day 2 were compared.

Results

Thirty-five TC patients had STE on admission. Compared with STEMI patients they had less prominent STE (median peak elevation 2 mm vs. 3 mm, P < 0.05), less reciprocal ST-segment depression and no abnormal Q-waves. By Day 2 all STEMI patients had pathological Q-waves but none of the TC patients.

Compared with NSTE-TC patients, NSTEMI patients had more ST-segment depression (28.2% vs. 0%, P < 0.05), but less T-wave inversion (33.8% vs. 11.3%, P < 0.05) on admission. By Day 2 the ECG criterion which best distinguished NSTE-TC from NSTEMI was the presence of T-wave inversion in ≥ 6 leads (sensitivity 74%, specificity 92%).

Conclusion

ECG changes seen in TC within two days of presentation are distinctive and important clues for clinicians to suspect the diagnosis.

Introduction

Takotsubo cardiomyopathy (TC) (also known as apical ballooning syndrome) is characterised by acute but rapidly reversible left ventricular (LV) dysfunction in the absence of obstructive coronary disease [1], [2]. At presentation TC typically mimic an acute myocardial infarction (AMI) and the initial electrocardiogram (ECG) exhibits ST-segment elevation in about a third of patients [3], [4], [5]. Because the in-hospital management of TC and AMI, both with and without ST-segment elevation is distinct, it would be useful to identify ECG features which facilitate the distinction between TC with and without ST-segment elevation, and ST-elevation myocardial infarction (STEMI) and non-ST-elevation MI (NSTEMI), respectively. Several ECG features of TC have been reported which may help to make these distinctions. These include absence of reciprocal changes, absence of abnormal Q-waves, absence of ST-segment elevation in lead V1, progressive QTc interval prolongation and widespread T-wave inversion [6], [7], [8].

Our aim was to examine the serial ECG patterns in TC patients, compare them with both STEMI and NSTEMI patients to identify the ECG features that may distinguish between these diagnoses, and evaluate their discriminative value both at admission and on Day 1 or 2 after admission.

Section snippets

Study population

The study population was prospectively identified from 3 coronary care units in the public hospitals in Auckland region (Middlemore Hospital, Auckland City Hospital and North Shore Hospital) between March 2004 and July 2010. One hundred consecutive patients who fulfilled the TC diagnostic criteria proposed by the Mayo Clinic group[9] and 100 patients presented with AMI (as described in the Third University Definition of Myocardial Infarction)[10] were identified. ECGs on admission, Day 1 and

Clinical characteristics

Table 1 summarises the clinical characteristics of the study population. TC patients were older (65 ± 11 years vs. 56 ± 7 years, P < 0.05) and there were more women in the TC group (95% vs. 25%, P < 0.05). TC patients with and without ST-segment elevation had similar risk factor distribution.

STE-TC versus STEMI

ECG findings of STE-TC and STEMI patients are presented in Table 2 and Fig. 1.

Discussion

To our knowledge, this study is the largest cohort published to date in Australasia and one of the largest cohorts internationally, evaluating ECG differences between TC and MI patients. The evolution of ECG changes in TC presenting with and without ST-segment elevation was similar suggesting a common underlying pathophysiology. Although at admission there were differences in the degree of ST change and incidence of Q-waves between MI and TC there was considerable overlap which limits the value

Clinical implications

It is unlikely that any ECG criteria will allow reliable discrimination of TC from MI at admission. However, in the appropriate clinical context (e.g. women who have experienced a recent emotional or physical stressor), either the presence of widespread and deep TWI in the absence of ST changes, or low grade ST segment elevation without Q-waves should raise the possibility of TC. However, given the clinical impact of delaying revascularisation in STEMI, our data do not support the ability of

Conclusion

Given the consequences of missing the diagnosis of a STEMI the diagnostic accuracy of ECG criteria were insufficient to reliably distinguish patients with TC from patients with STEMI at admission. In contrast, the differences were more marked after admission, with the absence of Q-waves being strongly suggestive of TC in those presenting with ST-segment elevation, and the late evolution of widespread and deep TWI being highly suggestive of TC in those without admission ST-segment elevation.

Conflict of interest

None.

Acknowledgement

None.

References (28)

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The authors take responsibility for all aspects of the reliability and freedom from bias of the data presented and their discussed interpretation.

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