A mimicry of an acute coronary syndrome

Abstract

Background: A 79-year-old woman was out in the garden having lunch on a hot summer day. She developed stabbing chest pains, more severe on her left side, associated with radiation down her left arm. Severity was 7 out of 10. There was no relief of pain with glyceryl trinitrate spray. Risk factors for ischaemic heart disease include hyperlipidaemia, being an ex-smoker (40 years), no history of diabetes or hypertension. There was a family history of her father having a myocardial infarction at the age of 54. Echocardiogram (ECG) revealed widespread deep symmetrical T-wave inversion in the chest leads and lateral limb leads.

Investigations: The patient’s serum creatine kinase level was 180 IU/litre (normal range 30–135), troponin I level was 6.56 g/litre (normal range 0–0.10), D-dimer was negative and random serum cholesterol level was 5.3 mmol/litre (3.8–5.2). Significant coronary stenoses were excluded. A left ventriculogram revealed a hyperkinetic base and a dyskinetic apical region of the left ventricle. Echocardiography showed normal valves, basal septal hypertrophy and a dilated akinetic apex, with the region of akinesia spanning more than the arterial territory.

Diagnosis: Takotsubo cardiomyopathy.

Management: Treatment with aspirin, angiotensin-converting enzyme (ACE) inhibitor, β blocker and a statin

CASE PRESENTATION

A 79-year-old woman presented to the accident and emergency department with acute left-sided stabbing chest pain, associated with an aching left arm and sweating. There was no radiation to any other areas, and she perceived the severity to be 7 out of 10. The pain was not relieved by glyceryl trinitrate spray given by the ambulance crew. She did not have heartburn. Risk factors for ischaemic heart disease include hyperlipidaemia, being an ex-smoker (40 years), no history of diabetes or hypertension. There was a family history of her father having a myocardial infarction at the age of 54. Her medications included atorvastatin 30 mg every night, calcium and vitamin D tablets and alendronate once a week. She is allergic to zinc oxide and penicillin.

On presentation, the patient was afebrile, with a blood pressure of 137/93 mm Hg, a regular pulse of 70 beats per min and a respiratory rate of 18 breaths per min with saturations of 100% on high-flow oxygen. Jugular venous pressure was not increased. Mild pitting oedema of her lower extremities was noted. Her lungs were clear on auscultation. Abdominal examination was unremarkable.

INVESTIGATIONS

Blood investigations revealed an increased level of troponin I of 6.56 µg/litre (normal range 0–0.10), creatine phosphokinase of 180 IU/litre (normal range 30–135) and a white cell count of 14.2×10⁹/litre (normal range 4.0–11.0).

Echocardiogram (ECG) was normal on admission. But subsequent ECGs revealed widespread symmetrical and broad T-wave inversion (fig 1). Cardiac catheterisation revealed a slightly irregular left coronary artery with no significant obstruction and a large dominant unobstructed right coronary artery. The left ventricle had a large symmetrical apical akinetic region.

Figure 1.

Widespread symmetrical and broad T-wave inversion.

The ECG revealed a normal left atrium, right atrium and right ventricle. The left ventricular apex and apical septum is hypokinetic and has an aneurysmal appearance, although it is hypokinetic rather than dyskinetic/akinetic (fig 2). There was basal septal hypertrophy. The overall left ventricular ejection fraction was 60%. Aortic, mitral and tricuspid valves were normal. There was no left ventricular outflow tract gradient.

Figure 2.

Echocardiogram revealing a normal left atrium, right atrium and right ventricle. The left ventricular apex and apical septum is hypokinetic and has an aneurysmal appearance. Basal septal hypertrophy was present. Aortic, mitral and tricuspid values were normal. There was no left ventricular outflow tract gradient.

A diagnosis of takotsubo cardiomyopathy was made.

OUTCOME AND FOLLOW-UP

Follow-up echocardiography at 5 weeks revealed normal biventricular function and morphology, with normal valve function. There was basal septal hypertrophy.

DISCUSSION

Dote et al¹ first described this form of cardiomyopathy in Japanese patients. The name relates to the peculiar shape of the left ventricle, which resembles an octopus fishing pot called a takotsubo. Takotsubo cardiomyopathy is increasingly recognised around the world.² The worldwide incidence is unknown. Takotsubo cardiomyopathy accounts for approximately 1% of admissions for suspected acute myocardial infarction in Japan. Most cases are reported in postmenopausal women.^2,3 Physiological or acute emotional stressors generally precede symptoms.⁴

Takotsubo cardiomyopathy has the following features: presentation of acute chest pain or dyspnoea after physiological or emotional stress that mimics acute myocardial infarction; electrocardiographic changes mimicking an acute myocardial infarction; absence of obstructive coronary vessels on coronary angiogram; absence of other catecholamine surge state, including pheochromocytoma, recent head trauma and intracranial bleeding; recovery of left ventricular function within 2–4 weeks of presentation.³

Presenting with overlapping symptoms and signs, it is difficult to distinguish takotsubo cardiomyopathy from an acute coronary syndrome. The described case mimicked a non-ST segment elevation myocardial infarction.

The presumed cause for the described case is dehydration leading to a reduction in venous return or vasodilatation, with consequent reduction in ventricular volume and generation of obstruction between the basal septum and the anterior mitral leaflet.

High ventricular pressure is required to overcome this obstruction leading to myocardial demand exceeding supply, with the apex bearing the brunt of this ischaemia.

This case illustrates the challenges of distinguishing takotsubo cardiomyopathy from an acute coronary syndrome. Further studies will hopefully enable early diagnosis of takotsubo cardiomyopathy, clarify its aetiology, refine its treatment and help in its prevention.

LEARNING POINTS

• Takotsubo cardiomyopathy is a condition in which there is transient left ventricle apex ballooning and transient ventricular failure.

• Takotsubo cardiomyopathy can present with acute chest pain resembling myocardial infarction.

• The ventricular failure resolves within 1 month.