Takotsubo cardiomyopathy

Takotsubo cardiomyopathy, also known as transient apical ballooning, stress-induced cardiomyopathy and simply stress cardiomyopathy, is a type of non-ischemic cardiomyopathy in which there is a sudden temporary weakening of the myocardium (the muscle of the heart). Because this weakening can be triggered by emotional stress, such as the death of a loved one, the condition is also known as broken heart syndrome ^[1].

The typical presentation of someone with takotsubo cardiomyopathy is a sudden onset of congestive heart failure or chest pain associated with EKG changes suggestive of an anterior wall heart attack. During the course of evaluation of the patient, a bulging out of the left ventricular apex with a hypercontractile base of the left ventricle is often noted. It is the hallmark bulging out of the apex of the heart with preserved function of the base that earned the syndrome its name "tako tsubo", or octopus trap in Japan, where it was first described. The etiology (cause) appears to involve high circulating levels of catecholamines (ie, adrenaline). Evaluation of individuals with takotsubo cardiomyopathy typically include a coronary angiogram, which will not reveal any significant blockages that would cause the left ventricular dysfunction. Provided that the individual survives their initial presentation, the left ventricular function improves within 2 months. Takotsubo cardiomyopathy is more commonly seen in post-menopausal women.^[2] Often there is a history of a recent severe emotional or physical stress.^[2]

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Etiology

The etiology of takotsubo cardiomyopathy is not fully understood, but several mechanisms have been proposed.

1. Wraparound LAD: The left anterior descending artery (LAD) supplies the anterior wall of the left ventricle in the majority of patients. If this artery also wraps around the apex of the heart, it may be responsible for blood supply to the apex and the inferior wall of the heart. Some researchers have noted a correlation between takotsubo and this type of LAD ^[3]. Other researchers have show that this anatomical variant is not common enough to explain takotsubo cardiomyopathy ^[4]. This theory would also not explain documented variants where the midventricular walls or base of the heart does not contract (akinesis).
2. Transient Vasospasm: Some of the original researchers of takotsubo suggested that multiple simultaneous spasms of coronary arteries could cause enough loss of blood flow to cause transient stunning of the myocardium ^[5]. Other researchers have shown that vasospasm is much less common than initially thought ^[6][7][8]. It has also been noted that when there are vasospasms, even in multiple arteries, that they do not correlate with the areas of myocardium that are not contracting ^[9].
3. Microvascular Dysfunction: The theory gaining the most traction is that there is dysfunction of the coronary arteries at the level where they are no longer visible by coronary angiography. This could include microvascular vasospasm, however it may well also have some similarities to the diseases such as diabetes mellitus. In such disease conditions the microvascular arteries fail to provide adequate oxygen to the myocardium.

It is likely that there are multiple factors at play which could include some amount of vasospasm, failure of the microvasculature, and an abnormal response to catecholamines (such as epinephrine and norepinephrine, released in response to stress).

Case series looking at large groups of patients report that some patients develop takotsubo after an emotional stressor, while others have a preceding clinical stressor (such as an asthma attack or sudden illness). Roughly one third of patients have no preceding stressful event ^[10].

Diagnosis

While the original case reports reported on individuals in Japan, takotsubo cardiomyopathy has been noted more recently in the United States and Western Europe. It is likely that the syndrome went previously undiagnosed before it was described in detail in the Japanese literature.

The diagnosis of takotsubo cardiomyopathy may be difficult upon presentation. The EKG findings are often confused with those found during an acute anterior wall myocardial infarction.^[2][11]

The diagnosis is made by the pathognomic wall motion abnormalities, in which the base of the left ventricle is contracting normally or are hyperkinetic while the remainder of the left ventricle is akinetic or dyskinetic. This is accompanied by the lack of significant coronary artery disease that would explain the wall motion abnormalities.

Histology

Focal myocytolysis is reported as an origin of this cardiomyopathy. No microbiological agent has been associated so far with Takotsubo cardiomyopathy. Kloner et al reported that a pathologic change in the myocardium was not demonstrated in the stunned myocardium.Infiltration of small mononuclear cells has been documented in some cases; these pathologic findings suggest that this cardiomyopathy is a kind of inflammatory heart disease, but not a coronary heart disease. There is also a report describing histologic myocardial damage without coronary heart disease.^[12]

Treatment

The treatment of takotsubo cardiomyopathy is generally supportive in nature. In individuals with hypotension, support with inotropic agents or an intra-aortic balloon pump have been used. In many individuals, left ventricular function normalizes within 2 months.^[13][14]

References

1. ^ http://www.medicalnewstoday.com/medicalnews.php?newsid=56666
2. ^ ^{a b c} Azzarelli S, Galassi AR, Amico F, Giacoppo M, Argentino V, Tomasello SD, Tamburino C, Fiscella A. (2006). "Clinical features of transient left ventricular apical ballooning". Am J Cardiol. 98 (9): 1273-6. PMID 17056345.
3. ^ Ibáñez B, Navarro F, Farré J, et al (2004). "[Tako-tsubo syndrome associated with a long course of the left anterior descending coronary artery along the apical diaphragmatic surface of the left ventricle.]" (in Spanish; Castilian). Revista española de cardiología 57 (3): 209–16. PMID 15056424.
4. ^ Inoue M, Shimizu M, Ino H, et al (2005). "Differentiation between patients with takotsubo cardiomyopathy and those with anterior acute myocardial infarction". Circ. J. 69 (1): 89–94. PMID 15635210.
5. ^ Kurisu S, Sato H, Kawagoe T, et al (2002). "Tako-tsubo-like left ventricular dysfunction with ST-segment elevation: a novel cardiac syndrome mimicking acute myocardial infarction". Am. Heart J. 143 (3): 448–55. PMID 11868050.
6. ^ Tsuchuhashi K et al. JACC 2001
7. ^ Kawai et al. JPJ 2000
8. ^ Desmet et al. Heart 2003
9. ^ Abe et al. JACC 2003
10. ^ Elesber, AA (July 2007). "Four-Year Recurrence Rate and Prognosis of the Apical Ballooning Syndrome". J Amer Coll Card 50 (5): 448-52.
11. ^ Bybee KA, Motiei A, Syed IS, Kara T, Prasad A, Lennon RJ, Murphy JG, Hammill SC, Rihal CS, Wright RS (2006). "Electrocardiography cannot reliably differentiate transient left ventricular apical ballooning syndrome from anterior ST-segment elevation myocardial infarction". J Electrocardiol. PMID 17067626.
12. ^ Dhar S, Koul D, Subramanian S, Bakhshi M (2007). "Transient apical ballooning: sheep in wolves' garb". Cardiol. Rev. 15 (3): 150-3. PMID 17438381.
13. ^ Akashi YJ, Nakazawa K, Sakakibara M, Miyake F, Koike H, Sasaka K. (2003). "The clinical features of takotsubo cardiomyopathy". QJM 96 (8): 563-73. PMID 12897341.
14. ^ Nyui N, Yamanaka O, Nakayama R, Sawano M, Kawai S. (2000). "'Tako-Tsubo' transient ventricular dysfunction: a case report". Jpn Circ J 64 (9): 715-9. PMID 10981859.