Takotsubo cardiomyopathy (TCM) is a neurocardiologic disorder thought to be triggered by a stressful event that causes reversible, transient heart failure.^1,2 The signs and symptoms of TC often mimic that of an acute myocardial infarction (MI) without demonstrable coronary artery stenosis or spasm, in which the apical portion of the heart balloons out and the base of the heart has preserved systolic function.³ TCM results in transient apical akinesis or dyskinesis of the left ventricle and a significantly depressed ejection fraction.⁴

History of TCM

TCM is also referred to as stress-induced cardiomyopathy, ampulla cardiomyopathy, left ventricular apical ballooning syndrome, or broken heart syndrome. It was first described in Japan in 1991. The term takotsubo cardiomyopathy originated from the Japanese word for an octopus trapping pot, a round vessel with a narrow neck that resembles the ventriculographic appearance of the heart at the end of systole.^1,5 The apical portion of the heart balloons out, while the base of the heart has preserved systolic function.³

Occurrence and Epidemiology

TCM accounts for approximately 2% of suspected acute MIs.⁶ Japan, Germany, the United States, Europe, Italy and Belgium have all reported increases in TCM over the past few years.⁵ Most patients are postmenopausal women who experience an acute emotional or physical stressor prior to symptom onset.² One study found that 90% of TCM cases occurred in women with a median age of 58 to 75.²

Etiology

Catecholamines and microvascular ischemia are possible mechanisms in TCM because these neurogenic particles are often elevated when people experience severe emotional and physical stress.² The majority of TCM cases appear to be precipitated by an intense emotional or physical condition. These include a death, a catastrophic medical diagnosis, terminal illness or life-changing treatment.⁵

More unconventional emotional stressors documented in cases of TCM include excessive gambling, tension related to financial difficulties, and professional sporting events. Physical conditions such as an exacerbation of chronic illness and fear related to domestic violence are also documented stressors.⁵ Environmental factors such as earthquakes and destructive weather conditions are recognized triggers.⁵ Some affected patients report no precipitating event, and these cases are considered idiopathic.⁷

Patient Presentation

The presentation of patients with TCM is similar to those with an acute MI. Symptoms include chest pain and dyspnea. In most cases, patients are hemodynamically stable but may present with hypotension or pulmonary edema.² Cardiac biomarkers, including creatinine kinase and cardiac troponin levels, increase slightly above normal.⁴ Electrocardiogram (ECG) findings often include ST elevation in precordial leads with subsequent T-wave inversion and Q-wave formation.⁶

These similar results make it impossible to distinguish between a diagnosis of TCM and a diagnosis of acute MI, and further testing is needed.¹

No pattern of patient or family history has been identified in TCM, but patients may have a history of hypertension, hyperlipidemia or atrial fibrillation.⁴

Pathophysiology

TCM seems to be associated with neuropsychologic, endocrine, hormonal and microvascular factors. Stress activates the fight-or-flight response, producing a rapid release of catecholamines.⁵ High levels of catecholamines may produce myocardial stunning and wall motion abnormalities in the heart.⁵ These events result in decreased cardiac contractility and grossly reduce the ability of the heart to pump and circulate blood volume.⁵ As the volume in the heart increases, tension against the ventricular wall increases and leads to a decreased contractile state, reducing cardiac output and increasing myocardial oxygen demands.⁵

During the stress response, the adrenal medulla also releases epinephrine, which normally causes increased myocardial contraction and a positive chronotropic effect.⁵ Epinephrine triggers the hepatic release of glucagon, which decreases the production of insulin.⁵ A hyperglycemic state develops because less active insulin is available to break down glucose.⁵ Metabolic abnormalities are more pronounced in the mid- and apical regions, possibly contributing to the formation of the classic apical ballooning pattern.¹

Another theory relates to estrogen deficiency. TCM may be associated with endothelial dysfunction and an increased risk of sympathetic-mediated myocardial dysfunction.¹ Nussinovitch et al1 state that the decreased use of hormone replacement therapy may be linked to the increasing reports of TCM.

Diagnostic Criteria

No consensus has been reached about the diagnostic criteria for TCM, but clinicians from the Mayo Clinic have proposed criteria that are commonly used:⁷

• Transient hypokinesis, akinesis or dyskinesis in the left ventricular mid- segments with or without apical involvement
• Regional wall motion abnormalities that extend beyond a single epicardial vascular distribution
• In most cases, a stressful trigger
• Absence of obstructive coronary disease or angiographic evidence of acute plaque rupture
• New electrocardiography abnormalities (ST-segment elevation and/or T-wave inversion) or modest elevation in cardiac troponin
• Absence of pheochromocytoma and myocarditis.

Diagnostic Studies

Unlike an acute MI presentation, TCM often produces ST elevation in many leads.¹ Also, cardiac biomarkers demonstrate a small, rapid increase to above normal levels as opposed to those presenting in acute MI (usually a significant increase of CK and troponin). Numerous causes of troponin release due to myocardial damage unrelated to myocardial ischemia exist, and discrimination is vital to provide timely and appropriate treatment.⁸ Laboratory studies may also reveal elevated B-type natriuretic peptide and plasma catecholamine levels.

Echocardiograms are the hallmark diagnostic tool for TCM.⁴ In affected patients, echocardiography reveals a hyperkinetic left ventricular base, midventricular hypokinesis and apical akinesis or dyskinesis causing marked apical ballooning and a severely reduced ejection fraction.⁴ To further rule out acute MI, a cardiac catheterization is performed.

Coronary angiography that is negative for lesions or significant stenosis provides greater evidence for TCM. Given the lack of less invasive diagnostic methods with a high degree of specificity for TCM, the combination of chest pain, a positive echocardiogram and negative cardiac coronary angiography confirm the diagnosis.⁴

Treatment

TCM is transient and usually resolves in a few weeks. Treatment is mainly symptomatic and supportive.¹ Initial treatment is similar to that for myocardial ischemia and cardiomyopathy and may include aspirin, beta-blockers, angiotensin-converting enzyme inhibitors, diuretics, anticoagulation and continuous telemetry monitoring.² Anti-anxiety drugs may be used to manage emotional distress.² Anxiety and pain may exacerbate the underlying pathophysiology.²

If a patient develops severe cardiogenic shock, he or she should be treated with an intra-aortic balloon pump for left ventricular support. Adrenergic agents and positive inotropes are contraindicated due to additional catecholamine stimulation and proarrhythmia effects.⁹ Arrhythmias due to QT prolongation are common in patients with TCM.⁷ Typically, antiarrhythmics are not administered prophylactically. Studies have shown that administration of magnesium sulfate is effective for ventricular tachycardia in the acute phase of TCM if the QT interval is prolonged.⁷

Prognosis

In hospitalized patients with TCM, the mortality rate is about 1%.¹ However, the premature death rate may be 2.5% to 8%.¹ Myocardial systolic failure usually wanes quickly, with cardiac recovery usually occurring within 7 to 30 days of symptom onset.¹ Complications of TCM may include left-sided heart failure with or without pulmonary edema, fatal ventricular rupture, evolvement of severe mitral regurgitation, stroke, pneumothorax or arrhythmias due to QT-interval prolongation.¹

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Complete restoration of myocardial function is a hallmark of TCM. Lack of a complete recovery may indicate a different diagnosis.¹ Overall, the reported recurrence rate of TCM is very low.¹

NPs and PAs may encounter patients with TCM in the acute or clinic setting during onset or during early recovery. An understanding of transient cardiomyopathy can facilitate correct diagnosis and proper care.²

In patients who present with acute MI symptoms, TCM should always be considered. Although a consensus has not been reached on diagnostic criteria, the existing recommendations can be used to aid in diagnosis. If cardiac catheterization does not show significant blockages and the echocardiogram shows a decreased ejection fraction, TCM may be the diagnosis.

As primary care providers, NPs and PAs are often in a position to recognize triggers and stressful events that may precipitate TCM. When this condition seems likely, the patient should be sent directly to the emergency department for further work-up. Follow-up care after the diagnosis of TCM includes reassuring the patient of a probable positive outcome, monitoring short-term medication therapy, and assessing left ventricular function in order to adjust treatment.

References

1. Nussinovitch U, et al. Distinguishing a heart attack from the "broken heart syndrome" (Takotsubo Cardiomyopathy). J Cardiovasc Nurs. 2011;26(6):524-529.

2. Thanavaro J, Thanavaro K. Apical ballooning syndrome: the broken heart syndrome. J Nurse Pract. 2009;5(10):767-772.

3. Coons JC, et al. Takotsubo cardiomyopathy. Am J Health Syst Pharm. 2009;66(6):562-566.

4. Brenner ZR, Powers J. Takotsubo cardiomyopathy. Heart Lung. 2008;37(1):1:1-7.

5. Griffin S, Logue B. Takotsubo cardiomyopathy: a nurse's guide. Crit Care Nurse. 2009;29(5): 32-41.

6. Milinis K, Fisher M. Takotsubo cardiomyopathy: pathophysiology and treatment. Post Grad Med J. 2012;88:530-538.

7. Akashi JY, et al. Takotsubo cardiomyopathy: a new form of acute, reversible heart failure. Circulation. 2008;118(25):2754-2762.

8. Agewells, et al. Troponin elevation in coronary vs. noncoronary disease. Eur Heart J. 2011;32:404-411.

9. Pore N, Burley M. When a broken heart is real: takotsubo cardiomyopathy. Nurse Pract. 2012;37(10): 404-411.

Mary Jones Dalzell is a student in the adult nurse practitioner program at the University of Cincinnati. She has completed a disclosure statement and reports no relationships related to this article.