TakoTsubo Cardiomyopathy

Introduction

TakoTsubo Cardiomyopathy (TTC), also known as broken-heart syndrome, apical ballooning syndrome or stress-induced cardiomyopathy. It is a reversible cardiomyopathy characterised by transient systolic ventricular dysfunction with a clinical presentation indistinguishable from acute myocardial infarction but in the absence of significant coronary artery obstruction. This condition is frequently precipitated by sudden, stressful emotional events, occasionally due to physiologic stress such as sepsis, non-cardiac surgery, and subarachnoid hemorrhage.

The term "Takotsubo"  was coined to describe the unusual shape of the left ventricular during systole. Typically, the mid to apical segments of the left ventricle are akinetic and the spared, basal walls exhibit compensatory hypercontractility. Takotsubo is a pot with round base and narrow neck used in Japan for trapping octopuses and has a similar appearance to this apical ballooning. 

TTC occurs most commonly in postmenopausal women and has a very good prognosis. Acutely, patients are often critically ill with heart failure, arrhythmias, shock, LVOT obstruction, thromboembolism but symptoms resolve quickly and death is rare.

Pathophysiology 

The pathophysiologic basis of TTC has not been conclusively determined but several mechanisms have been proposed. The underlying histopathological findings on myocardial biopsy are distinctly different from those of coagulation necrosis seen in typical atherosclerotic epicardial artery occlusion and myocardial infarction. 

• Catecholamine overload and myocardial stunning 
• Multi-vessel coronary artery spasm with resultant ischemia and stunned myocardium 
• Spontaneously aborted myocardial infarction 
• Microvascular dysfunction and myocarditis

Clinical presentation 

TTC has been reported to account for 1-3% of all acute coronary cases. About 90% of cases reported are in post-menopausal women ages 58-75 years old.  The clinical presentation of TTC is often identical to acute myocardial infarction (AMI). Most patients with takotsubo cardiomyopathy present with typical anginal chest pain, dyspnea, ischemic changes on electrocardiogram (ECG), and elevated cardiac markers.  Emotional stress, such as news of the death of a family member, divorce, or public speaking, is implicated as the trigger in approximately two-thirds of patients. 

ECG changes and cardiac biomarkers 

The most common abnormality on the ECG is ST elevation and T-wave inversion in the precordial leads. However, there may be some population differences in presenting signs and specific ECG changes should be considered suggestive but not diagnostic of TTC. Modest elevation of cardiac biomarkers is often observed in TTC.

ECG Image (TTC) from LIFTL

Diagnosis 

Due to the dramatic clinical presentation and high suspicion for acute myocardial infarction, most patients undergo emergent coronary angiography. Typical findings in TTC are normal epicardial coronaries, mild non-obstructive atherosclerosis, or rarely coexistent coronary artery disease. Therefore, TTC is a diagnosis of exclusion which can only be made after coronary angiography. It should be on the differential diagnosis in any post-menopausal women over 50 years old presenting with chest pain and ischemic ECG changes particularly in the setting of emotional stress. Furthermore it should also be considered in critically ill patients with sudden hemodynamic compromise and/or heart failure. 

Mayo Clinic proposed diagnostic criteria in 2004 for TTC which includes four components:

(1) Transient hypokinesis, akinesis, or dyskinesis of the left ventricular mid seg- ments with or without apical involvement; the regional wall motion abnormalities extend beyond a single epicardial vascular distribution; a stressful trigger is often, but not always present 

(2) Absence of obstructive CAD or angiographic evidence of acute plaque rupture 

(3) New electrocardiographic abnormalities (either ST-segment elevation and/or T wave inversion) or modest elevation in cardiac troponin 

(4) Absence of pheochromocytoma and myocarditis

Cardiac imaging 

Ventriculography reveals apical ballooning, with characteristic sparing of the basal segments and akinesis of the mid and apical left ventricle. However, variants of this pattern have been described. In patients with typical TTC, the wall motion abnormality usually extends beyond the distribution of a single coronary artery. 

Echocardiography can detect and measure the degree of left ventricular outflow (LVOT) obstruction and associated systolic motion of the anterior mitral valve and significant mitral regurgitation. 

LVOT obstruction is reported to occur in 25% patients and can have a major impact on acute management. In patients with hemodynamic compromise and shock, inotropes would worsen this situation and betablockers and pure vasopressor pharmacologic or mechanical support may be needed. The typical findings on cardiac MRI include the absence of delayed gadolinium hyperenhancement. This is specific to TTC and can help differentiate it from myocarditis and acute myocardial infarction in which delayed hyperenhancement is present.

Treatment 

Takotsubo cardiomyopathy has an excellent prognosis, with full and early recovery in virtually all patients. The majority of patients have normalization of LVEF within a week and all patients by 4-8 weeks. Long-term survival is similar to the general population. 

• The goals of treatment are usually conservative, supportive care. The therapy is guided by the patient’s clinical presentation and hemodynamic status. Despite the possible causal role of catecholamines in the disorder, patients who present in cardiogenic shock, and in the absence of LVOT obstruction, may be treated with inotropes. 
• Alternatively patients may derive further benefit from IABP and VADs. 
• If LVOT obstruction is present with cardiogenic shock, inotropes should be avoided and phenylphrine is the pressor agent of choice often combined with betablockade.
• Anticoagulation is reserved for those with ventricular thrombus or evidence of embolic events. 

Take Home

• Takotsubo cardiomyopathy is an acquired cardiomyopathy which is a differential diagnosis of acute coronary syndrome. 
• It is characterized by transient systolic ventricular dysfunction with regional wall motion abnormalities beyond a single vascular territory in the absence of significant epicardial coronary artery obstruction. 
• Acute emotional/ physical stressor immediately preceding the acute coronary syndrome is a common presentation. Catecholamine excess and cardiotoxicity is the most likely underlying mechanisms.
• Supportive treatment is the mainstay of therapy.

References:

1. Kurisu S, Kihara Y. Clinical management of takotsubo cardiomyopathy. Circ J. 2014. 78 (7):1559-66. 
2. Prasad A, Lerman A, Rihal CS. Apical ballooning syndrome (Tako-Tsubo or stress cardiomyopathy): a mimic of acute myocardial infarction. Am Heart J. 2008 Mar. 155(3):408-17.
3. Bybee KA, Kara T, Prasad A, et al. Systematic review: transient left ventricular apical ballooning: a syndrome that mimics ST-segment elevation myocardial infarction. Ann Intern Med. 2004 Dec 7. 141(11):858-65.
4. Merchant EE, Johnson SW, Nguyen P, Kang C, Mallon WK. Takotsubo cardiomyopathy: a case series and review of the literature. WestJEM. 2008. 9:104-11.