Takotsubo Cardiomyopathy Workup

Updated: Jan 17, 2017
  • Author: Eric B Tomich, DO; Chief Editor: Erik D Schraga, MD  more...
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Workup

Approach Considerations

Cardiac markers, specifically troponin I (TnI) and tropnin T (TnT), are elevated in 90% of patients with takotsubo cardiomyopathy (TCM), though to a lesser magnitude than is seen in ST-segment elevation myocardial infarction (STEMI). The brain natriuretic peptide (BNP) level is also frequently elevated.

As with any patient in whom acute coronary syndrome (ACS) is suspected, electrocardiography (ECG) should be the initial test obtained soon after presentation to the emergency department (ED).

Transthoracic echocardiography (TTE) provides a quick method of diagnosing wall-motion abnormalities typically seen in TCM, specifically hypokinesis or akinesis of the midsegment and apical segment of the left ventricle (LV). The diagnosis of TCM is typically confirmed with cardiac angiography.

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Laboratory Studies

In patients with TCM, the mean TnT level at the time of admission has been found to be 0.49 ng/mL (normal, <0.01), and the mean TnI level has been reported as 4.2 ng/mL (normal, <0.04); during hospitalization, mean peak values for TnT and TnI have been demonstrated to be 0.64 and 8.6 ng/mL, respectively.

As mentioned, the BNP level is also frequently elevated, especially in those patients demonstrating left heart failure; it is an indicator of increased LV end-diastolic pressures that result from the stunned myocardium.

TCM mimics STEMI. In a study of 66 consecutive patients who were hospitalized with TCM and 66 patients with STEMI, cardiac biomarkers were determined during 12 hours from admission and compared with demographic, clinical, and echocardiographic findings. [29] Investigators found evidence that the following ratios were capable of distinguishing TCM from STEMI at an early stage:

  • Ratio of N-terminal pro-BNP (NTproBNP) to TnI
  • Ratio of NTproBNP to creatine kinase MB (CKMB) mass
  • Ratio of NTproBNP to ejection fraction (EF)

Of these, the most accurate marker was the NTproBNP-to-TnI ratio. [29]

Several studies looked at levels of circulating catecholamines in the acute phase and found that nearly 75% of patients had elevations markedly higher than did patients with STEMI. [30, 31]

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Echocardiography

As previously stated, TTE provides a quick method of diagnosing wall-motion abnormalities typically seen in TCM, [32] specifically hypokinesis or akinesis of the midsegment and apical segment of the LV. Perhaps most important, these wall-motion abnormalities extend beyond the distribution of any single coronary artery.

The LV ejection fraction (LVEF) can be estimated by means of echocardiography, cardiac magnetic resonance imaging (MRI), or left ventriculography. Mean LVEF on admission has been found to be in the range of 20-49%.

Echocardiography is commonly used in following the resolution of the cardiomyopathy and impaired LV function, with LVEF improving to 59-76% on average, by day 18. (See the images below.)

Echocardiogram of a patient with takotsubo cardiom Echocardiogram of a patient with takotsubo cardiomyopathy during diastole several days after presenting to the emergency department.
Echocardiogram of a patient with takotsubo cardiom Echocardiogram of a patient with takotsubo cardiomyopathy during systole, which demonstrates apical akinesis. Ejection fraction is 40%.
Echocardiogram of a patient with takotsubo cardiom Echocardiogram of a patient with takotsubo cardiomyopathy during systole, nearly 2 months after presenting to the emergency department. Note the improved contractility of the apex. Ejection fraction increased from 40% to 65%.
Echocardiogram of a patient with takotsubo cardiom Echocardiogram of a patient with takotsubo cardiomyopathy during diastole, approximately 2 months after presenting to the emergency department.
Echocardiogram focused on left ventricle of a pati Echocardiogram focused on left ventricle of a patient with takotsubo cardiomyopathy during diastole.
Echocardiogram focusing on left ventricle of a pat Echocardiogram focusing on left ventricle of a patient with takotsubo cardiomyopathy during systole. Note apical akinesis.
Echocardiogram focusing on left ventricle of a pat Echocardiogram focusing on left ventricle of a patient with takotsubo cardiomyopathy during systole, approximately 2 months after presenting to the emergency department. Note improved apical contraction.
Echocardiogram focusing on left ventricle of a pat Echocardiogram focusing on left ventricle of a patient with takotsubo cardiomyopathy during diastole, approximately 2 months after presenting to the emergency department.
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Cardiac Angiography

The diagnosis of TCM is typically confirmed in the cardiac catheterization laboratory. In a review of 240 patients diagnosed with TCM, 211 were found to have completely normal coronary arteries, whereas the remainder had noncritical stenoses. The prevalence of normal coronary arteries by angiography in patients presenting with STEMI ranges from 1% to 12%. Aside from TCM, this phenomenon may be explained by transient vessel occlusion with spontaneous thrombolysis, by vasospasm, or by drug effects.

Left ventriculography is perhaps the best imaging modality for demonstrating the pathognomonic wall motion and evaluating LVEF. [22, 23] (See the images below.)

Coronary angiogram of a patient with takotsubo car Coronary angiogram of a patient with takotsubo cardiomyopathy demonstrating normal coronary arteries.
Coronary angiogram of a patient with takotsubo car Coronary angiogram of a patient with takotsubo cardiomyopathy demonstrating normal coronary arteries.
Ventriculogram during systole in a patient with ta Ventriculogram during systole in a patient with takotsubo cardiomyopathy demonstrating apical akinesis.
Ventriculogram during diastole in a patient with t Ventriculogram during diastole in a patient with takotsubo cardiomyopathy.
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Other Imaging Techniques

Chest radiographs in TCM are often normal, but they may demonstrate pulmonary edema.

Cardiac MRI is increasingly being used as a diagnostic modality that is uniquely suited for establishing the diagnosis of TCM by accurately visualizing regional wall-motion abnormalities, quantifying ventricular function, and identifying reversible injury to the myocardium by the presence of edema/inflammation and the absence of necrosis/fibrosis. [33, 34, 35]

In addition to evaluating wall-motion abnormalities and LVEF, cardiac MRI has been found to differentiate TCM, which is characterized by the absence of delayed gadolinium hyperenhancement, from myocardial infarction (MI) and myocarditis, in which the opposite occurs.

Although not indicated in the initial evaluation of patients with TCM, reports are emerging of the use of coronary computed tomography (CT) angiography (CTA) in the subsequent evaluation of patients with the disorder. [36]

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Electrocardiography

As with any patient in whom ACS is suspected, ECG should be the initial test obtained soon after presentation to the ED. ST-segment elevation (67-75%) and T-wave inversion (61%) are the most common abnormalities seen on the initial ECG. Ninety-five percent of ST-segment elevations have been found to involve the precordial leads and to be maximal in leads V2 -V3. In comparison with patients with STEMI from left anterior descending (LAD) coronary artery occlusion, patients with TCM had significantly lower amplitude of ST-segment elevations. (See the images below.)

Electrocardiogram of a patient with takotsubo card Electrocardiogram of a patient with takotsubo cardiomyopathy demonstrating ST-segment elevation in anterior and inferior leads.
Electrocardiogram from the same patient examined i Electrocardiogram from the same patient examined in the previous ECG, obtained several days after initial presentation. This demonstrates resolution of ST-segment elevation, and now with diffuse T-wave inversion and poor R-wave progression.

An initially normal or nonspecific ECG finding is seen in 15% of patients with TCM. Diffuse T-wave inversions tend to occur in the days and weeks following presentation as the ST segments normalize. TCM cannot be reliably differentiated from STEMI solely on the basis of ECG findings. [22, 26]

In a retrospective study of 33 patients with TCM, the authors proposed ECG criteria to distinguish TCM from anterior acute MI in those who presented within 6 hours of symptom onset. The combination of absent abnormal Q waves, absent reciprocal changes, lack of ST-segment elevation in lead V1, and presence of ST-segment elevation in lead aVR had more than 91% sensitivity and 96% specificity for TCM. [37]

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