INTRODUCTION — Stress-induced cardiomyopathy, also called apical ballooning syndrome, broken heart syndrome, and takotsubo cardiomyopathy, is an increasingly reported syndrome generally characterized by transient systolic dysfunction of the apical and/or mid segments of the left ventricle that mimics myocardial infarction (MI), but in the absence of obstructive coronary artery disease [1-15].
Stress-induced cardiomyopathy was first described in Japan [1,2] and was subsequently reported in non-Asian populations, including the United States [6,7,10] and Europe [9,16].
The term “takotsubo” is taken from the Japanese name for an octopus trap, which has a shape that is similar to the apical ballooning configuration of the left ventricle (LV) in systole in the "typical" form of this disorder. In the more commonly described "typical" type of stress-induced cardiomyopathy, the contractile function of the mid and apical segments of the LV are depressed, and there is compensatory hyperkinesis of the basal walls, producing a balloon-like appearance of the distal ventricle with systole. Less commonly (17 percent of cases in one series), the ventricular hypokinesis is restricted to the midventricle ("atypical") with relative sparing of the apex [17]. About a third of cases involve both right and left ventricles.
Stress-induced cardiomyopathy is much more common in women than men [3,4,7,15,16]. In a review of ten prospective series, women accounted for 80 to 100 percent of cases, with a mean age of 61 to 76 years [15].
PATHOGENESIS — The onset of stress-induced cardiomyopathy is frequently but not always triggered by an acute medical illness or by intense emotional or physical stress (eg, death of relatives, particularly if unexpected, domestic abuse, arguments, catastrophic medical diagnoses, devastating financial or gambling losses, natural disasters) [4,5,7-10,18].
The pathogenesis of this disorder is not well understood. It is not known why this disorder affects postmenopausal women disproportionately or why the left ventricular mid-cavity and apex are predominantly affected. Although the clinical presentation simulates that of an acute MI, coronary arteriography typically shows no obstructive lesions [4,7], and only a minority of patients display coronary spasm with acetylcholine provocation [4].
Postulated mechanisms include catecholamine excess, coronary artery spasm, and microvascular dysfunction. Alternatively, there may be dynamic mid-cavity or left ventricular outflow tract obstruction which may contribute to apical dysfunction. Analogous permanent (rather than transient) apical outpouchings develop in patients with hypertrophic cardiomyopathy and mid-ventricular obstruction. (See "Types and pathophysiology of obstructive hypertrophic cardiomyopathy", section on 'Midcavity obstructive HCM'.)
A potential role for plaque rupture and thrombosis with spontaneous thrombolysis has not been established and the results of intravascular ultrasound (IVUS) studies are mixed. Although one IVUS study found evidence of mid left anterior descending (LAD) coronary artery plaque rupture in 5 of 5 patients diagnosed with stress-induced cardiomyopathy [19], other IVUS series found no evidence of culprit lesions in the LAD [20,21].
Physical or emotional stress — A number of features of stress-induced cardiomyopathy, including its association with physical or emotional stress [4,5,7-10,18], suggest that this disorder may be caused by diffuse catecholamine-induced microvascular spasm or dysfunction, resulting in myocardial stunning [22], or by direct catecholamine-associated myocardial toxicity [23]. In some patients with stress-induced cardiomyopathy, the only apparent stressor is exposure to catecholamine or beta-agonist drugs in routine clinical doses [24]. (See "Clinical syndromes of stunned or hibernating myocardium".)
Support for a possible pathogenic role for catecholamines comes from studies in which plasma catecholamines were measured at presentation [8,25-27]. Combining the results from these series, plasma norepinephrine levels were elevated in 26 of 35 patients (74 percent) [22]. Elevated catecholamine levels and reversible left ventricular ballooning have also been observed in a rat model of immobilization-induced stress [28].
The magnitude of catecholamine excess associated with this disorder was illustrated in a report that measured plasma catecholamine levels in 13 patients with stress-induced cardiomyopathy and seven patients with a Killip class III MI (table 1) [8]. Plasma catecholamines were significantly higher in the patients with stress-induced cardiomyopathy as compared to those with MI: epinephrine (1264 versus 376 pg/mL) and norepinephrine (2284 versus 1100 pg/mL). However, elevation in blood catecholamine levels is not uniformly present and some studies have reported normal levels [29].
Further support for the catecholamine hypothesis is provided by observations of a similar reversible cardiomyopathy with global or focal dysfunction in patients with pheochromocytoma [30] (see "Clinical presentation and diagnosis of pheochromocytoma"), and in the setting of acute brain injury, which has also been postulated to be related to catecholamine excess [31]. (See "Cardiac complications of stroke", section on 'Neurogenic cardiac damage'.)
The following observations support the hypothesis of vascular dysfunction that may be catecholamine-induced:
The following observations support the hypothesis of catecholamine-induced myocardial effects:
Predisposing factors — Since stress-induced cardiomyopathy occurs in a minority of postmenopausal women, it is likely that predisposing factors increase susceptibility in some individuals. Recently, there have been two reports of familial cases involving two sisters in one family and a mother and daughter in another family raising the possibility of a genetic predisposition [37,38]. However, early genetic analyses have not identified a mutation or polymorphism [39,40]. Moreover, there may be a higher prevalence of chronic anxiety disorders preceding the illness in patients with stress induced cardiomyopathy [41].
Critical illness — The incidence of stress-induced cardiomyopathy in a medical intensive care unit (ICU) population was prospectively evaluated in a series of 92 patients with a non-cardiac diagnosis and no prior history of cardiac disease [42]. All patients underwent serial echocardiography on admission and on hospital days three and seven, specifically evaluated for LV apical ballooning. The following findings were reported:
The high incidence of transient LV apical ballooning in this series requires validation in larger series, but it appears that this phenomenon is not uncommon in a medical ICU population.
PREVALENCE — Some of the best available estimates come from four small series of consecutive patients presenting with a suspected acute coronary syndrome (ACS) [10,25,26,43], which were included in a larger systematic review [22]. Each of these series included 10 to 16 patients with stress-induced cardiomyopathy, accounting for approximately 1.7 to 2.2 percent of cases presenting with suspected ACS. A similar prevalence of 1.2 percent was reported from a registry of 3265 patients with troponin-positive ACS [16].
CLINICAL PRESENTATION — The clinical presentation of stress-induced cardiomyopathy is similar to that of an acute MI [3,4,7]. The most common presenting symptom is acute substernal chest pain, but some patients present with dyspnea, syncope, shock, or electrocardiographic abnormalities.
Acute complications of stress-induced cardiomyopathy can include heart failure, tachyarrhythmias (including ventricular tachycardia and ventricular fibrillation), bradyarrhythmias, mitral regurgitation and cardiogenic shock [3,4,7,9]. In a review of 12 prospective series (with 13 to 88 subjects), pulmonary edema occurred in 0 to 44 percent of cases and intra-aortic balloon counterpulsation was used in 0 to 18 percent of patients [15]. Left ventricular outflow tract (LVOT) obstruction, induced by left ventricular basal hyperkinesis, can contribute to the development of shock and cause severe mitral regurgitation or the murmur of hypertrophic cardiomyopathy (see "Auscultation of cardiac murmurs", section on 'Subvalvular outflow obstruction') [44]. Apical thrombus formation and stroke have also been described [24,45].
A preliminary report proposed a risk score to predict the likelihood of acute heart failure based on the presence or absence of the following three variables: age >70 years, presence of a physical stressor, and left ventricular ejection fraction (LVEF) <40 percent [46]. In the development cohort of 118 patients, the likelihood of developing acute heart failure was <10 percent in the absence of these risk factors. With one, two, or three risk factors present, the risk was approximately 28, 58, and 85 percent, respectively. A similar gradient of risk was observed when the risk score was applied to the 52 patients in the validation cohort.
Data on the characteristics of stress-induced cardiomyopathy come from relatively small case series [3-5,7-10,25,44,47,48]. A systematic review of 14 series, including a total of 286 patients, provides a more comprehensive assessment of this disorder [22]. The range of findings from these reports is illustrated by the following:
Diagnosis — The diagnosis of stress-induced cardiomyopathy should be suspected in postmenopausal women who present with an acute coronary syndrome after intense psychologic stress in whom the clinical manifestations and ECG abnormalities are out of proportion to the degree of elevation in cardiac biomarkers [11]. Apical ballooning (typical variant) and/or midventricular hypokinesis is usually seen on left ventriculography or echocardiography [3-5,7,9,16,25]. In a minority of cases, the transient left ventricular hypokinesis is restricted to the midventricular segments ("atypical variant" or “apical sparing variant”) without involvement of the apex [16]. In one series of 256 patients, 82 percent were apical, 17 percent midventricular, and 1 percent basal, with 34 percent of cases demonstrating right ventricular involvement [17].
Coronary angiography typically demonstrates either normal vessels or mild to moderate coronary atherosclerosis. Obstructive coronary artery disease may rarely coexist by virtue of its prevalence in the population at risk [51]. Some investigators have hypothesized that stress cardiomyopathy is not a distinct clinical entity, but rather a manifestation of aborted anterior MI in patients with a long ‘wrap around’ left anterior descending artery [19]. Transient occlusion in such a vessel, with subsequent spontaneous thrombus lysis, could produce apical stunning and wall-motion abnormalities that would improve over followup. However, in one series the prevalence of ‘wrap-around’ left anterior descending artery in stress-induced cardiomyopathy was found to be low (27 percent) and comparable to that in patients diagnosed with anterior ST elevation MI [51].
The following cardiac magnetic resonance (CMR) imaging features may be helpful in the diagnosis of stress-induced cardiomyopathy:
A number of other syndromes in addition to stress-induced cardiomyopathy have been associated with ST segment changes in the absence of significant coronary artery disease, including cardiac syndrome X, variant (Prinzmetal's) angina, myocarditis, and cocaine abuse. As noted above, similar reversible cardiomyopathy with global or focal dysfunction has been observed in patients with pheochromocytoma and in the setting of acute brain injury [30,31]. These conditions are discussed in detail separately. (See "Cardiac syndrome X: Angina pectoris with normal coronary arteries", section on 'Acute coronary syndrome' and "Variant angina" and "Clinical manifestations and diagnosis of myocarditis in adults" and "Evaluation and management of the cardiovascular complications of cocaine abuse" and "Clinical presentation and diagnosis of pheochromocytoma" and "Cardiac complications of stroke", section on 'Neurogenic cardiac damage'.)
The following are the proposed Mayo Clinic diagnostic criteria, all four of which are required for the diagnosis [3,14]:
There are rare exceptions to these criteria such as patients in whom the regional wall motion abnormality is limited to a single coronary territory, and the occasional patient with obstructive coronary atherosclerosis who develops stress-induced cardiomyopathy.
An important issue is how the possible diagnosis of stress-induced cardiomyopathy should influence the evaluation of a suspected acute coronary syndrome. We suggest the following approach:
In the later scenario, the diagnosis of stress-induced cardiomyopathy may later be suggested by such clinical features as the absence of critical stenoses on coronary angiography, modest cardiac enzyme elevations and recovery of LV function. However, none of these features is diagnostic, as they may also reflect successful early fibrinolysis.
Right ventricular involvement — Most reports of stress-induced cardiomyopathy have focused on transient dysfunction of the left ventricle. However, there is emerging evidence that the right ventricle (RV) is also affected in some cases [53,54].
The frequency and significance of RV involvement was illustrated in a series of 34 patients with stress-induced cardiomyopathy who underwent cardiac magnetic resonance (CMR) imaging [54]. Nine patients (26 percent) had RV wall motion abnormalities. Patients with RV dysfunction had lower LV ejection fractions compared to patients with normal RV function (40 versus 48 percent), and were also more likely to have pleural effusions. At a mean of one year after presentation, follow-up CMR showed improvement or resolution of RV dysfunction in eight of nine patients.
TREATMENT AND PROGNOSIS — Despite the severity of the acute illness, stress-induced cardiomyopathy is a transient disorder managed with supportive therapy. Conservative treatment with resolution of the physical or emotional stress usually results in rapid resolution of symptoms.
General therapy — Once the diagnosis of stress-induced cardiomyopathy has been made, therapy is based upon the patient's overall clinical condition. There are no controlled data to define the optimal medical regimen, but it is reasonable to treat these patients with standard medications for left ventricular systolic dysfunction. These include ACE inhibitors, beta blockers, and diuretics as necessary for volume overload [3]. Aspirin is also suggested in the presence of coexisting coronary atherosclerosis [3,14]. (See "Overview of the therapy of heart failure due to systolic dysfunction".)
Stress-induced cardiomyopathy is a transient disorder. In the absence of clinical trial data, the appropriate duration of therapy is not known. We usually treat patients with the standard HF medical regimen until there is recovery of systolic function which occurs in one to four weeks in most cases. However, because the condition may recur, we often continue adrenergic blockade with either beta-blockers or combined alpha and beta-blockers indefinitely in the absence of contraindications or intolerance.
Hypotension and shock — Patients who are in shock should undergo urgent echocardiography to determine if left ventricular outflow tract (LVOT) obstruction is present, which has been described in 13 to 18 percent of cases [3,44].
Without left ventricular outflow tract obstruction — Patients without significant LVOT obstruction who are hypotensive due to pump dysfunction can be treated cautiously with inotropes such as dobutamine and dopamine. Since the condition is potentially caused by catecholamine excess, the impact of sympathomimetics remains to be established. In a patient with hypotension due to pump failure, inotropic agents may induce LVOT obstruction, but the degree is usually mild [7]. A change in the therapeutic approach is not necessary if mild LVOT obstruction develops. Intra-aortic balloon counterpulsation (IABP) is the preferred therapy when there is marked LV dysfunction associated with severe hypotension or shock [7].
With left ventricular outflow tract obstruction — In contrast to hypotension due only to pump failure, hypotension associated with LVOT obstruction should NOT be treated with inotropic agents, because they can worsen the degree of obstruction [7,44].
The recommended approach to patients with moderate-to-severe LVOT obstruction includes the use of beta blockers, which can improve hemodynamics by causing resolution of the obstruction. (See "Medical therapy in hypertrophic cardiomyopathy".) In addition, in the absence of significant pulmonary congestion, the patient should be fluid resuscitated [3,44].
As with patients in shock due to pump failure, those with LVOT obstruction may benefit from an IABP, although there is a slight risk that afterload reduction from the IABP will worsen the degree of obstruction [7]. The initial treatment in such patients, however, should be to treat the underlying pathophysiological mechanisms with fluid replacement, beta blockers, and other negative inotropic agents. In patients with hypotension, whether with or without significant LVOT obstruction, who do not respond to initial medical therapy and volume resuscitation, we suggest the use of an IABP.
In patients with LVOT obstruction and severe hypotension who either do not tolerate or do not adequately respond to beta blockers, an alpha agonist may be added with caution and close monitoring. Phenylephrine is a pure alpha-adrenergic agonist that may reduce the gradient by increasing afterload, thereby improving overall hemodynamics. This treatment may be helpful to support blood pressure while a beta blocker is administered to reduce inotropy. However, the vasoconstrictive effects of alpha agonists may be harmful, particularly in these patients who can be prone to coronary vasospasm. Thus, if phenylephrine is used, it should be done with a high degree of caution and very close monitoring of hemodynamics and tissue perfusion.
Thromboembolism — The potential risk of intraventricular thrombus formation and systemic embolization should be addressed. Echocardiography (and CMR if available) should include evaluation for potential thrombus as well as assessment of the extent of wall motion abnormality.
Data are scant to identify suitable criteria for use of anticoagulation to prevent thromboembolism in patients with stress cardiomyopathy.
We recommend approximately three months of anticoagulation if intraventricular thrombus is detected. The duration of anticoagulation may be modified based on the rate of recovery of cardiac function and resolution of the thrombus. For patients without thrombus but with severe left ventricular dysfunction, we suggest anticoagulation until akinesis or dyskinesis has resolved or for three months, whichever is shorter.
Prognosis — Reported in-hospital mortality rates have ranged from 0 to 8 percent [3,4,7,15]. In a large series of 136 patients, there were three in-hospital deaths [24]. Patients who survive the acute episode typically recover normal ventricular function within one to four weeks [4,7-9,32]. In two series, for example, the mean LVEF increased from 29 percent at presentation to 63 percent at a mean of six days [7] and from a median of 20 percent at presentation to 60 percent at two to four weeks [8].
The longest follow-up data comes from a study of 100 patients [55]. Over a mean follow-up of 4.4 ± 4.6 years, 31 patients continued to have episodes of chest pain and 10 patients had recurrence of apical ballooning syndrome. Seventeen patients died, but there was no difference in survival compared to an age- and gender-matched population.
SUMMARY AND RECOMMENDATIONS — Stress-induced cardiomyopathy is an increasingly reported syndrome characterized by transient apical LV dysfunction in the absence of significant coronary artery disease.
Clinical manifestations and diagnosis
Management — The initial management of stress-induced cardiomyopathy is largely supportive, including hydration and an attempt to alleviate the triggering physical or emotional stress. The role of additional medications and the appropriate duration of therapy are not established. Most experts favor at least the short-term use of standard medications for heart failure due to systolic dysfunction. (See "Overview of the therapy of heart failure due to systolic dysfunction".)
We approach hemodynamically stable patients diagnosed with stress-induced cardiomyopathy in the following manner (see 'General therapy' above):
Hypotension — Some patients with stress-induced cardiomyopathy will develop hypotension and shock, which could be due either to severe systolic dysfunction or to LVOT obstruction. Because it will influence the choice of treatment, patients who develop severe hypotension should undergo urgent echocardiography to determine if LVOT obstruction is present.
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