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Takotsubo cardiomyopathy – A rare form of transient LV dysfunction

August 2, 2016

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Takotsubo cardiomyopathy – A rare form of transient LV dysfunction By: Tina Bastin Lexington High School, MA Abstract: Takotsubo Cardiomyopathy occurs in individuals when they experience unexpected, sudden stress that affects them emotionally and/ or physically. In this study, data was obtained from various patients of different ages ranging from 45-55 years old from Japan and also from different genders. After following up with an echocardiogram, females were found to have a higher risk of heart failure than males. When a patient encountered more than one emotionally stressful event, their risk to the disease decreased. This particular study demonstrates the different circumstances that impact the level of heart failure and compares the different genders and ages encountering it, thereby aiding in diagnosis and early treatment to prevent future complications. Introduction: Takotsubo Cardiomyopathy, originating from Japan, is a heart failure due to unexpected, sudden stress. It is known to be prominent in women 50 years and older. This disease is influenced by gender and age, and may also have a genetic predisposition. Other prominent symptoms include chest pain, electrocardiogram abnormalities, swelling, shock, and abnormal movement in the left ventricle (located on the bottom, left chamber of the heart below the left atrium). Takotsubo cardiomyopathy, also referred to as stress-induced cardiomyopathy, is a syndrome characterized by transient dysfunction of the apical portion of the left ventricle (located on the lower, left chamber of the heart), with compensatory hyperkinesis of the basal walls, producing ballooning of the apex (Figure 1). This is much more common in postmenopausal women. Takotsubo cardiomyopathy was first identified by Sato et al. (1990), who compared Takotsubo to an octopus fishing pot with a round bottom and narrow neck. The syndrome is characterized by various factors: acute substernal chest pain with ST-segment elevation and/or T-wave inversion in precordial leads, absence of significant coronary artery (an artery supplying blood to the heart) narrowing by angiography, immense psychological stress or acute medical illness immediately preceding and triggering cardiac symptoms, and minimal myocardial enzymes released. When these enzymes are present, they help promote biochemical reactions—such as controlling how the heart muscles contract and managing the heart’s energy process. Acute mental or physical stress causes a weakening of the left ventricle, which is vital for pumping blood with the highest pressure. The left ventricle is also crucial because it carries and pumps oxygen-rich blood, received from the left atrium, to the rest of the body system into the systemic circulation. Unfortunately, no treatments are available specifically for this disease. However, some medications that are helpful for this syndrome are ACE inhibitors, angiotensin converting enzyme inhibitor, and beta blockers, beta adrenergic blocking agents. ACE inhibitors are used to decrease a patient’s blood pressure, causing their heart rate to decrease, and also used to treat hypertension. This is because ACE inhibitors dilate the blood vessels, improving the quantity of blood pumped, lowering blood pressure, and increasing blood flow. All this results in the amount of energy and work the heart performs to decrease, preventing the weakening of the heart. In addition, beta blockers have been shown to decrease the impact of stress hormones upon the left ventricle. Beta blockers work similarly to ACE inhibitors. Beta blockers block the effects of the hormone epinephrine/ adrenaline, which is a hormone that is released from the medulla of the adrenal glands to the bloodstream when an individual encounters strong emotions that cause high levels of stress. This in turn causes the heart to beat more slowly using less energy, reducing blood pressure and causing the blood vessels to dilate and improve blood flow. If beta blockers were not used and epinephrine was release to the bloodstream, this would cause an increase in heart rate, more heart energy and muscle strength to be used, causing an increase in blood pressure, which would further weaken the left ventricle, stimulating Takotsubo Cardiomyopathy. a.) b)

Figure 1. When an individual encounters an unexpected mentally or physically stressful event, the left ventricle swells up (a) and has a similar configuration to the shape of an octopus trap (b). Takotsubo is derived from the Japanese word meaning octopus trap (Internet Scientific Publications). Case Study: A 55 year old female with a history of hypothyroidism, GERD (gastroesophageal reflux disease- acid reflux disease) was walking to work when she tripped and fell, hitting her head and chest. She had LOC (level of consciousness), perhaps seizure-like activity, which lasted approximately one minute. She was brought by an Emergency Medical Technician (EMT) to the emergency room (ER); the patient was unresponsive but her vitals were normal. Her subsequent examination was unremarkable. Initial troponin (cardiac enzyme) and BNP (brain natriuretic peptide) were normal. Subsequently her troponin and BNP were elevated and normalized in a few days. Her EKG (electrocardiogram) showed T-wave inversions in the lateral leads. Later when she regained consciousness, she complained of left and midsternal sharp chest pain, nausea, shortness of breath, and diaphoresis. Echocardiogram results showed severe hypokinesia to akinesia of the bulk of the anterior wall, apex, and inferior apex, mid and apical septum. In the interim her neurologic status improved and her head CT showed no evidence of bleeding. Coronary angiography showed normal coronary arteries and confirmed echo finding-ejection fraction was 40 – 45%. The remainder of the left ventricular function was normal. This was consistent with Takotsubo cardiomyopathy. She was started on angiotensin- converting enzyme inhibitor, beta-blocker, aspirin and discharged home in a stable condition. Patient Analysis and Method: Day 1. A 55-year old woman tripped over a curb when she was walking to work. When she fell, she hit the left temporal region of her head, above the eyes, and became unconscious. She endured a small seizure and was admitted to the ER immediately. Once in the ER, she complained of a sharp pain in the left side of her chest. She also had a nauseating sensation, shortness of breath, and sweating. She denied having a history of cerebral palsy, shown in Figure 2. However, one of the symptoms she described was subscapular pain (back pain), which she claims she had for four days.

Figure 2. The patient had subscapular pain (back pain). Upon reviewing her past medical records, it was revealed that she had GERD (gastroesophageal reflux disease), a digestive disorder taking place in the lower esophagus. She had hypothyroidism which is where the activity of the thyroid gland is abnormally low, causing mental dysfunctions such as depression and impaired memory. She had also undergone gastric bypass surgery and a hysterectomy. Looking back at the patient’s personal records, she had a history of smoking and drug use. She also consumed alcohol occasionally. She is married with two children and works as a bank teller. After reviewing her family records, both her father and brother passed away due to myocardial infarction, a heart disease where blood stops flowing to parts of the heart, causing chest pain. The father and brother died young, between the ages of 41-55. The woman, who is approximately the same age as her brother and father when they died, is enduring a form of heart disease. After a ROS (review of systems) she was declared positive for chest pain, sweats, nausea, GERDS, and anemia. She denied having a history of depression, however.

Normal Vitals
Heart Rate	80
Breathing Rate	132/70
RR ?	18
O2 Saturation	98%
Weight	155 Lbs.
Temperature	98.8

Patient’s arterial blood gas (ABG) was normal.

Arterial Blood Gas
pH	7.43
pCO2	39.1
pO2	56
HCO3	25.3
O2 sats	87.5
FiO2	100%

Patient’s diagnostic studies. Results were normal.

Diagnostic Studies	mEq (milliequivalent)
Na	145
K	3.6
Cl	106
HCO3	27
Glucose	105
BUN	11
Cr	0.6
Ca	8.9
Alk.phos	116
ALT	58
AST	43
Bili	0.8

EKG Results: T-wave inversion in I and aVL.

Figure 3 (Image from UpToDate) Diagnostic Studies: In the chest x-ray, lymph node enlargement was apparent. Hypothesis: this was inherited because her mother suffered and died from lymphoma. She was also suffering from alveolar edema (fluid accumulation in the lungs) but had a normal sized heart.

(Cardiology Journal) Figure 4: Diagram of CXR:Chest x-ray shows bilateral edema. Computed Tomography (CT): can be used to see the organs in-depth, unlike x-rays. CT showed low attenuation in the brain stem.

(Cardiology Journal) Figure 5: Image of CT Head: Duration in ER: The CXR (chest x-ray) indicated she had bilateral edema, which is an excess fluid in the cavities or tissues of the body, and was then given Lasix, which prevents the body from absorbing an excess amount of salts, which then allowed the salt to pass to the urine, instead of retaining it Her O2 saturation and blood pressure then dropped, so she was given dopamine gtt, which helps with the central nervous system (CNS).

(Cardiology Journal) Figure 6: Image of echocardiogram Based on the patient’s echocardiogram, it was potentially possible for an acute AMI- acute myocardial infarction, also known as a heart attack, although the troponin level, a protein complex involved in muscle contraction, and BNP were normal. Coronary angiography, a test that uses dye to show the insides of the coronary arteries was performed. This revealed that the LAD (left anterior descending) coronary was problematic;the left ventricular angiogram showed there was acute hypokinesia of the anterior. The ejection fraction was between 40-45, which was abnormal. This is consistent with the hypothesis that this patient has acute stunned myocardium- heart attack due to unexpected shock.

Figure 7: Image of Cardiac Catheterization Cardiology Journal The patient was transferred to the ICU for continuous cardiac supervision. Day 2. The patient’s BNP increased, brain natriuretic peptide. Another echocardiogram was performed on day 5; the patient had an improved LV, but acute hypokinesia continued to be prominent.

Cardiology Journal Figure 8: Image of ECHO After consultation with a neurologist, a MRI (magnetic resonance imaging) was ordered, which produced normal results. The conclusion after these findings- a secondary brief seizure due to a concussion and unexpected shock. Ultimately, stress triggered the patient’s heart attack, which is also known as Takotsubo cardiomyopathy, broken-heart syndrome. CONCLUSION: Catecholamine cardiotoxicity and adrenoceptor hyperreactivity have been suggested as potential causes of Takotsubo cardiomyopathy. Identification of Takotsubo syndrome is important because its management and prognosis differs significantly from that of an AMI (acute myocardial infarction) that results from thrombotic occlusion of a coronary atheromatous plaque. Left ventricle function normalizes within several days or weeks in most cases. Prognosis is good without any form of treatment provided the patient survives the severe heart failure state. Development/ Pathogenesis: There is no specific pattern or path to follow. However, this disease is triggered by intense emotional or physical stress. For instance, some stress inducing factors are financial loss, car accident, domestic violence, and unexpected loss of a family member or friend.

References

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