Metabolic evidence of myocardial stunning in takotsubo cardiomyopathy: a positron emission tomography study

Metabolic remodeling in takotsubo syndrome

The heart requires a large and constant supply of energy that is mainly the result of an efficient metabolic machinery that converges on mitochondrial oxidative metabolism to maintain its continuous mechanical work. Perturbations in these metabolic processes may therefore affect energy generation and contractile function directly. Metabolism characteristics in takotsubo syndrome (TTS) reveals several metabolic alterations called metabolic remodeling, including the hyperactivity of sympathetic metabolism, derangements of substrate utilization, effector subcellular dysfunction and systemic metabolic disorders, ultimately contributing to the progression of the disease and the development of a persistent and long-term heart failure (HF) phenotype. In this review, we explore the current literature investigating the pathological metabolic alterations in TTS. Although the metabolic dysfunction in takotsubo hearts is initially recognized as a myocardial metabolic inflexibility, we suggest that the widespread alterations of systemic metabolism with complex interplay between the heart and peripheral tissues rather than just cardiometabolic disorders per se account for long-term maladaptive metabolic, functional and structural impairment under this condition. Therapeutic strategies with the recent evidence from small clinical and animal researches, especially for targeting substrate utilization and/or oxidative stress, might be promising tools to improve the outcome of patients with TTS beyond that achieved with traditional sympathetic inhibition and symptomatic therapies.

A Review of Nuclear Imaging in Takotsubo Cardiomyopathy

Takotsubo cardiomyopathy or Takotsubo Syndrome (TTS) is a reversible left ventricular dysfunction syndrome that is increasingly being recognized. Recent advances in nuclear imaging have allowed us to study TTS in greater detail. We searched the PubMed and Medline databases and identified 53 publications with 221 patients reporting nuclear imaging findings in TTS. The age of the patients ranged from 17 to 87 years and were predominantly women (88.2%). The TTS variant was apical (typical) in 170 (76.9%), mid-ventricular in 23 (10.4%), and basal (reverse TTS) in 2 (0.9%). Cardiac perfusion was assessed using 99mTc sestamibi (MIBI) SPECT, 99mTc tetrofosmin SPECT, 201Tl SPECT, 82Rb PET, 201Tl SPECT, and 13N ammonia PET. Additional studies used were 123I MIBG SPECT, 123I BMIPP SPECT, 18F FDG PET, 67Ga citrate, and 11C hydroxy-ephedrine. A perfusion defect was seen in 69 (31.2%), and an inverse perfusion-metabolism mismatch (normal or near-normal perfusion with absent myocardial metabolic activity) was seen in 183 (82.8%) patients. Nuclear imaging has a significant role in evaluating, diagnosing, and prognosticating patients with TTS. As nuclear imaging technology evolves, we will surely gain more insights into this fascinating disorder.

Various Aspects of Fasting on the Biodistribution of Radiopharmaceuticals

It is demonstrated that fasting can alter the biodistribution of radiopharmaceuticals in nuclear medicine. Various studies have highlighted that fasting is interpreted to be easy for physicians during PET study, fasting is one of the most important factors determining the usefulness of this protocol. It is well documented that fasting can suppress normal ¹⁸F-FDG PET uptake during nuclear cardiology. However, there is no consensus about the usefulness of fasting on radiopharmaceuticals, especially on ¹⁸F-FDG in PET imaging, but special attention should be paid to the setting of the fasting duration. Nevertheless, it does seem we still need extensive clinical studies in the future. The present study aims to review the various aspects of fasting, especially metabolic alteration on radiopharmaceutical biodistribution. In this study, we focused more on the effect of fasting on ¹⁸F-FDG biodistribution, which alters its imaging contrast in cardiology and cancer imaging. Therefore, shifting substrate metabolism from glucose to free fatty acids during fasting can be an alternative approach to suppress physiological myocardial uptake.

Novel Imaging and Genetic Risk Markers in Takotsubo Syndrome

Takotsubo syndrome (TTS) is an increasingly recognized condition burdened by significant acute and long-term adverse events. The availability of novel techniques expanded the knowledge on TTS and allowed a more accurate risk-stratification, potentially guiding clinical management. The present review aims to summarize the recent advances in TTS prognostic evaluation with a specific focus on novel imaging and genetic markers. Parametric deformation analysis by speckle-tracking echocardiography, as well as tissue characterization by cardiac magnetic resonance imaging T1 and T2 mapping techniques, currently appear the most clinically valuable applications. Notwithstanding, computed tomography and nuclear imaging studies provided limited but promising data. A genetic predisposition to TTS has been hypothesized, though available evidence is still not sufficient. Although a genetic predisposition appears likely, further studies are needed to fully characterize the genetic background of TTS, in order to identify genetic markers that could assist in predicting disease recurrences and help in familial screening.

The role of multimodality imaging in takotsubo cardiomyopathy

Takotsubo cardiomyopathy (TC) is a syndrome of transient left ventricular (LV) dysfunction mimicking acute coronary syndrome. Although the mechanisms underlying the occurrence of TC are unknown, several imaging techniques contribute to its diagnosis. Here we review the current knowledge about TC, in particular, the pathophysiology and the role of imaging including nuclear cardiovascular medicine.

Takotsubo cardiomyopathy: FDG myocardial uptake pattern in fasting patients. Comparison of PET/CT, SPECT, and ECHO results

BACKGROUND

The aim of this study was to assess the accumulation pattern of 18F-FDG in fasting patients with takotsubo cardiomyopathy (TTC) and to correlate the results with perfusion scintigraphy and echocardiography.

METHODS

18 consecutive patients with TTC were identified by clinical symptoms, cardiac catheterization, and echocardiography. Coronary angiography (CA) and transthoracic echocardiography (TTE) were performed on the day of the onset of symptoms. An assessment of myocardial perfusion (99mTc-MIBI) and glucose metabolism (18F-FDG) was performed within 18 days.

RESULTS

SPECT showed no regional perfusion abnormalities in 10/18 patients, and a mild perfusion defect was found in 8/18 patients. Perfusion abnormalities were limited to apical and para-apical regions. In 8/18 cases, there was an increased selective apical 18F-FDG accumulation. In 10/18 cases, in spite of the fastened 18F-FDG protocol, slightly inhomogeneous 18F-FDG uptake was present in the entire myocardium: with relatively reduced uptake of 18F-FDG in the apical region and LV mid-segments.

CONCLUSION

This study demonstrated the heterogeneous nature of myocardial 18F-FDG accumulation in patients with TTC. Selective, preferential apical 18F-FDG uptake in almost half of the patients confirms an existing disorder of glucose metabolism, similar to that observed in stunned or hibernated myocardium.

Takotsubo cardiomyopathy: Pathophysiology and role of cardiac biomarkers in differential diagnosis

Takotsubo cardiomyopathy (TC) is characterized by reversible ventricular dysfunction, not limited to the distribution of an epicardial coronary artery. A disease primarily afflicting post-menopausal women, it is frequently mistaken for acute anterior wall myocardial infarction. Alternatively called Stress Cardiomyopathy, physical or emotional triggers are identified in only three fourths of TC patients. Long considered a benign condition, recent findings suggest poor short term prognosis similar to acute coronary syndrome (ACS). Despite the widely recognized pathophysiological role of catecholamine excess, its diagnostic role is uncertain. TC is suspected based on typical wall motion abnormalities in ventriculogram or echocardiogram. Several additional electrocardiographic, laboratory and imaging parameters have been studied with the goal of clinical diagnosis of TC. While several clinical clues differentiate it from ACS, a clinical diagnosis is often elusive leading to avoidable cardiac catheterizations. Natriuretic peptides (NPs), a family of peptide hormones released primarily in response to myocardial stretch, play a significant role in pathophysiology, diagnosis as well as treatment of congestive heart failure. TC with its prominent ventricular dysfunction is associated with a significant elevation of NPs. NPs are elevated in ACS as well but the degree of elevation is typically lesser than in TC. Markers of myocardial injury such as troponin are usually elevated to a higher degree in ACS than in TC. This differential elevation of NPs and markers of myocardial injury may play a role in early clinical recognition of TC.

Pathophysiology of Takotsubo Syndrome

Originally described by Japanese authors in the 1990s, Takotsubo syndrome (TTS) generally presents as an acute myocardial infarction characterized by severe left ventricular dysfunction. TTS, however, differs from an acute coronary syndrome because patients have generally a normal coronary angiogram and left ventricular dysfunction, which extends beyond the territory subtended by a single coronary artery and recovers within days or weeks. The prognosis was initially thought to be benign, but subsequent studies have demonstrated that both short-term mortality and long-term mortality are higher than previously recognized. Indeed, mortality reported during the acute phase in hospitalized patients is ≈4% to 5%, a figure comparable to that of ST-segment-elevation myocardial infarction in the era of primary percutaneous coronary interventions. Despite extensive research, the cause and pathogenesis of TTS remain incompletely understood. The aim of the present review is to discuss the pathophysiology of TTS with particular emphasis on the role of the central and autonomic nervous systems. Different emotional or psychological stressors have been identified to precede the onset of TTS. The anatomic structures that mediate the stress response are found in both the central and autonomic nervous systems. Acute stressors induce brain activation, increasing bioavailability of cortisol and catecholamine. Both circulating epinephrine and norepinephrine released from adrenal medullary chromaffin cells and norepinephrine released locally from sympathetic nerve terminals are significantly increased in the acute phase of TTS. This catecholamine surge leads, through multiple mechanisms, that is, direct catecholamine toxicity, adrenoceptor-mediated damage, epicardial and microvascular coronary vasoconstriction and/or spasm, and increased cardiac workload, to myocardial damage, which has a functional counterpart of transient apical left ventricular ballooning. The relative preponderance among postmenopausal women suggests that estrogen deprivation may play a facilitating role, probably mediated by endothelial dysfunction. Despite the substantial improvement in our understanding of the pathophysiology of TTS, a number of knowledge gaps remain.

The natural history of takotsubo syndrome: a two-year follow-up study with myocardial sympathetic and perfusion G-SPECT imaging

PURPOSE

To investigate changes in sympathetic activity, perfusion, and left ventricular (LV) functionality in takotsubo cardiomyopathy (TTC) patients from onset (T₀) to post-onset conditions at 1 month (T₁), 1-2 years (T₂, T₃).

METHODS

Twenty-two patients (70 ± 11 years) underwent serial gated single photon emission tomography (G-SPECT) studies with ¹²³I-mIBG and ^99mTc-Sestamibi. Statistics were performed using ANOVA/Sheffé post-hoc, correlation test, and receiver operating characteristic (ROC) curve analysis (p < 0.05).

RESULTS

Patients presented at T₀ with LV ballooning and reduced early-late mIBG uptake (95%, 100%), left ventricular ejection fraction (LVEF)_G-SPECT (86%) and perfusion (77 %). Adrenergic dysfunction was greater in apex, it overlaps with contractile impairment, and both were more severe than perfusion defect. During follow-up, LVEF_G-SPECT, contractility, and perfusion were normal, while 82% and 90% of patients at T₁ and 50% at T₂ and T₃ continued to show a reduced apical early-late mIBG distribution. These patients presented at T₀-T₁ with greater impairment of adrenergic function, contractility, and perfusion. A relationship was present within innervation and both perfusion and contractile parameters at T₀ and T₁, and between the extent of adrenergic defect at T₃ and both the defect extent and age at T₀ (cut-off point 42.5%, 72 years).

CONCLUSION

Outcome for TTC is not limited to a reversible contractile and perfusion abnormalities, but it includes residual adrenergic dysfunction, depending on the level of adrenergic impairment and age of patients at onset. The number of patients, as well as degree of perfusion abnormalities were found to be higher than those previously reported possibly depending on the time-interval between hospital admission and perfusion scan.

Takotsubo cardiomyopathy with use of salbutamol nebulisation and aminophylline infusion in a patient with acute asthma exacerbation

Takotsubo cardiomyopathy, apical ballooning syndrome or stress-induced cardiomyopathy is characterised by transient left ventricular dysfunction, mimicking myocardial infarction in the absence of obstructive coronary artery disease or acute plaque rupture on coronary angiography. The exact mechanism of myocardial dysfunction in Takotsubo cardiomyopathy is unknown; however, due to its association with physical and emotional stress, it is postulated that catecholamines play a central role in its pathogenesis. We present a case of a patient who was admitted with acute asthma exacerbation and was treated with β-2 agonist nebulisation and intravenous aminophylline. During her hospital stay she developed Takotsubo cardiomyopathy.

Takotsubo cardiomyopathy systematic review: Pathophysiologic process, clinical presentation and diagnostic approach to Takotsubo cardiomyopathy

Takotsubo cardiomyopathy (TTC) is characterized by transient left ventricular apical ballooning with the absence of coronary occlusion, which typically occurs in older women after emotional or physical stress. The pathophysiology of TTC is not well established, though several possible causes such as catecholamine cardiotoxicity, metabolic disturbance, coronary microvascular impairment and multivessel epicardial coronary artery spasm have been proposed. A number of diagnostic criteria have been suggested in the world and not unified as single, but the most common accepted one is Mayo Clinic proposed criteria. Since the clinical presentation of TTC is usually similar to acute coronary syndrome, differential diagnosis is essential to exclude other diseases and also for its treatment. Imaging modality including echocardiogram, angio CT and cardiac MRI, and lab tests for catecholamine, troponin T, creatine kinase MB and B-type natriuretic peptide can be useful to differentiate TTC from other diseases. Prognosis is generally favorable and in-hospital mortality is from 0% to within 10%.

Reverse Takotsubo Cardiomyopathy following Inadvertent Intrathecal Injection during Percutaneous Epidural Neuroplasty

Stress induced cardiomyopathy (SIC) is becoming increasingly described as an underdiagnosed complication during common medical procedures. Reverse Takotsubo cardiomyopathy (RTC) is a variant of SIC that involves the basal and mid-ventricular segments and spares the apical segments. The authors present a rare case of RTC, following an inadvertent intrathecal injection during percutaneous epidural neuroplasty. Although the precise mechanism involved remains unclear, the direct neurohumoral effects of the hyperbaric anaesthetics and adhesiolytics appear to have resulted in a catecholamine surge and myocardial stunning that precipitated the SIC.

Standard and advanced echocardiography in takotsubo (stress) cardiomyopathy: clinical and prognostic implications

Echocardiography is frequently the initial noninvasive imaging modality used to assess patients with takotsubo cardiomyopathy (TTC). Standard transthoracic echocardiography can provide, even in the acute care setting, useful information about left ventricular (LV) morphology as well as regional and global systolic or diastolic function. It allows the differentiation of different LV morphologic patterns according to the localization of wall motion abnormalities. A "circumferential pattern" of LV myocardial dysfunction characterized by symmetric wall motion abnormalities involving the midventricular segments of the anterior, inferior, and lateral walls should be considered suggestive of TTC and included in the differential diagnosis of acute coronary syndromes. Moreover, advanced echocardiographic techniques, including speckle-tracking, myocardial contrast, and coronary flow studies, are providing mechanistic and pathophysiologic insights into this unique syndrome. Early identification of any potential complications (i.e., LV outflow tract obstruction, reversible moderate to severe mitral regurgitation, right ventricular involvement, thrombus formation, and cardiac rupture) are crucial for the management, risk stratification, and follow-up of patients with TTC. Because of the dynamic evolution of the syndrome, comprehensive serial echocardiographic examinations should be systematically performed. This review focuses on these aspects of imaging and the increasing understanding of the clinical and prognostic utility of echocardiography in TTC.

Epidemiology and clinical profile of Takotsubo cardiomyopathy

First described in Japan over 2 decades ago, takotsubo cardiomyopathy (TTC) has emerged as a unique cardiomyopathy with world-wide recognition, mimicking acute coronary syndrome. In early TTC experience, typical patients were older women, with a triggering emotional event, ST-segment elevation, and apical ballooning left ventricular (LV) contraction pattern. However, TTC is now more heterogeneous, occurring in males and younger individuals, without ST-segment elevation, as a spontaneous event in the absence of a trigger, and with diverse LV contraction patterns. Furthermore, TTC is more common than initially thought, now constituting 10% of women with suspected acute coronary syndrome. TTC is also associated with a broader range of psychological or physical triggers, including presentation during outpatient medical evaluations or hospitalization for acute illness. Although TTC has been considered a benign condition, it now carries a small but important risk for adverse outcomes, including cardiac arrest in 5%. Hemodynamic instability requiring intervention with vasopressor drugs or intra-aortic balloon pump is necessary in 15% and in-hospital mortality is approximately 5%, largely because of refractory cardiogenic shock or irreversible major comorbid conditions. Although complete cardiac recovery usually occurs rapidly, post-hospital survival may be less than the general population of similar age, largely because of concomitant illnesses. TTC may reoccur in up to 10% of patients, but β-blocking drugs are not absolutely preventive for initial or subsequent events.

Usefulness of myocardial positron emission tomography/nuclear imaging in Takotsubo cardiomyopathy

AIM: To analyse and summarize all the articles related to positron emission tomography and Takotsubo cardiomyopathy (TTC).

METHODS: We performed a systematic review of the existing literature on positron emission tomography/nuclear imaging and Takotsubo cardiomyopathy using PUBMED database. We combined search terms such as “takotsubo”, “takotsubo syndrome”, “myocardial positron emission tomography”, “positron emission tomography”. All case reports were excluded. The list included only four articles which were reviewed by two independent investigators. It was not possible to undertake a formal meta-analysis because of the heterogeneity of the studies; therefore, we made a narrative synthesis of the collected data.

RESULTS: Nuclear medicine techniques can be useful employed in the differential diagnosis of TTC from an acute coronary syndrome (ACS). In fact, transient left ventricular (LV) apical ballooning is a syndrome frequently misdiagnosed as an ACS and can mimic symptoms of myocardial infarction with ST-T segments changes on electrocardiography (ECG), a limited release of myocardial enzyme, mainly reported after sudden emotional or physical stress, and an akinesis or dyskinesis of the left ventricle apex which are completely reversible in a few weeks. In the studies included in this review, nuclear medicine techniques have demonstrated a discrepancy between normal perfusion and a reduced glucose utilization in TTC, commonly known as “inverse flow metabolism mismatch”. This suggests that apical ballooning represents a transient metabolic disorder on the cellular level, rather than a structural contractile disease of the myocardium, due to a transient decrease of glucose metabolism that might be related to a coronary microcirculation impairment followed by prolonged myocardial stunning.

CONCLUSION: Nuclear medicine techniques can be usefully used for the diagnosis of TTC and can increase our knowledge of the pathophysiological mechanisms of TTC.

Diagnostic utility of 123I-BMIPP imaging in patients with Takotsubo cardiomyopathy

OBJECTIVE

Takotsubo cardiomyopathy is a cardiac syndrome with an acute onset defined by chest symptoms and ST segment elevation on electrocardiograms. Takotsubo cardiomyopathy is sometimes misdiagnosed as acute myocardial infarction (AMI). Therefore a non-invasive diagnostic method is needed to be established for setting up appropriate strategies. The purpose of this study was to detect myocardial metabolic abnormalities and to determine the diagnostic usefulness of (123)I-beta-methy-iodophenyl pentadecanoic acid ((123)I-BMIPP) imaging in patients with takotsubo cardiomyopathy.

METHODS AND RESULTS

We examined 16 patients with takotsubo cardiomyopathy and 12 with AMI in the left anterior descending artery. All patients were studied with resting (123)I-BMIPP imaging. Total defect score (TDS) of (123)I-BMIPP and perfusion were semi-quantitatively determined with single-photon emission computed tomography (SPECT) imaging using a 17-segment 5-point model. TDS of (123)I-BMIPP were 4.8 ± 2.7 in patients with Takotsubo cardiomyopathy and 22.4 ± 10.7 in AMI. The ratio of summed BMIPP defect score of non-apical to apical segments in Takotsubo cardiomyopathy was smaller than that of the patients with AMI (0.1 ± 0.1 vs. 1.1 ± 0.7, p < 0.0001), indicating that (123)I-BMIPP abnormalities were exclusively observed the in apical area. The ratio of summed perfusion defect scores of non-apical to apical segments in takotsubo cardiomyopathy did not differ significantly from that of AMI (0.52 ± 0.6 vs. 0.57 ± 0.3, p = NS). Summed BMIPP defect score in the apical area of takotsubo cardiomyopathy was larger than that of perfusion defect score (3.9 ± 2.7 vs. 1.8 ± 1.8, p = 0.04).

CONCLUSION

Impaired metabolic metabolism exclusively in the apical region was observed by (123)I-BMIPP SPECT images in takotsubo cardiomyopathy. These typical metabolic SPECT features of the disease can be utilized on differential diagnosis of takotsubo cardiomyopathy.

Takotsubo cardiomyopathy: overview

Takotsubo cardiomyopathy (TTC) is a unique acute syndrome characterized by transient left ventricular systolic dysfunction in the absence of significant coronary artery disease, occurring mostly in postmenopausal women after emotional and/or physical stress. Given the nonspecific symptoms and signs, a high clinical index of suspicion is necessary to detect the disease in different clinical settings and scenarios. Noninvasive multimodality imaging may be useful to distinguish this cardiomyopathy from other acute cardiac and thoracic diseases. Coronary angiography remains, however, mandatory to differentiate TTC from acute coronary syndromes. This article reviews the clinical features and management of TTC and some new insights.

Contrast echocardiography reveals apparently normal coronary perfusion in a rat model of stress-induced (Takotsubo) cardiomyopathy

AIMS

Stress-induced cardiomyopathy (SIC) is an important differential diagnosis to acute myocardial infarction (AMI) that is associated with significant morbidity and mortality. The typical hallmark of SIC is left-ventricular apical akinesia but preserved function in basal segments. Catecholamines are postulated to play an important role in SIC but the precise pathophysiology is incompletely understood. Whether myocardial perfusion of the affected segments is impaired in SIC has been debated and remains unknown.

METHODS AND RESULTS

Myocardial contrast echocardiography (MCE) was used to study regional myocardial perfusion in a rat model of SIC. Twelve rats received 50 mg/kg isoproterenol (ISO) i.p. and were continuously monitored by MCE. Apical and basal perfusion were estimated and expressed as a ratio at baseline, 5, 10, 20, 30, 40, 50, 60, 70, 80, and 90 min post-ISO. The rats developed typical apical ballooning after 43 ± 9 min post-ISO injection. The ratio of apical:basal perfusion was close to 1.00 at all time-points and never dropped below 0.89 (95% CI never extended below 0.73). Light and electron microcoscopical investigation revealed no structural damage of myocardial vessels.

CONCLUSION

Apical perfusion is not impaired in the early phase of SIC in this rat model.

Scintigraphic imaging in Tako-Tsubo cardiomyopathy

Tako-Tsubo cardiomyopathy (TTC, stress cardiomyopathy) is more common in elderly women and its symptoms can be deceptively similar to those of acute myocardial infarction. Although coronary arteries appear normal on coronary angiograms, a shape like a Tako-Tsubo (a Japanese fishing pot for trapping octopuses) can be observed on left ventriculogram. TTC is generally considered to be a trigger for sudden cardiac death. The onset mechanism of TTC is still controversial. Catecholamine cardiotoxicity and/or coronary circulation disturbance due to coronary microvascular spasm and/or neurogenic stunned myocardium as a result of autonomic imbalance are considered to be the most likely causes. In this review, we assess the usefulness of myocardial scintigraphic imaging in TTC patients on the basis of the results obtained from earlier studies and case reports in order to establish a deeper understanding of the pathophysiological mechanism of this syndrome.

Takotsubo cardiomyopathy--a clinical review

Stress cardiomyopathy is characterised by reversible left ventricular dysfunction. It simulates an acute coronary syndrome (ACS), presenting with precordial pain or dyspnoea, changes of the ST segment, T wave, or QTc interval on electrocardiogram, and raised cardiac enzymes. Typical findings are disturbances of segmental contractility (apical hypokinesia or akinesia), with normal epicardial coronary arteries. The true prevalence is unknown, as the syndrome may be under-diagnosed; it is more common in postmenopausal women. There is usually a trigger in the form of physical or psychological stress. The electrocardiographic, echocardiographic, and ventriculographic changes resolve spontaneously over a variable period of time (from days to months). There are a number of pathophysiological theories, none of which has been shown to be definitive, suggesting that all of them may be involved to some extent. The prognosis is generally favourable, and recurrence is very rare.

Takotsubo Cardiomyopathy: A Review of the Literature

Although takotsubo cardiomyopathy is a rare entity, it is an important differential in patients presenting with symptoms, signs, and electrocardiographic changes suggestive of an acute myocardial infarction. Since it was first recognized in 1991, it has gained increasing attention worldwide; however, its etiology and consequently the optimal management still remains unclear. Here, the authors provide a review of the current literature accompanied with images of a typical case from our department.

Transient left ventricular dysfunction syndrome: patho-physiological bases through nuclear medicine imaging

BACKGROUND

Takotsubo cardiomyopathy (TTC) is a novel heart disease, mimicking acute myocardial infarction. The term "transient left ventricular dysfunction syndrome" (TLVDS) seems to be more appropriate since variant forms of TTC sparing apical segments (mid-ventricular ballooning syndrome (MVBS) and inverted TTC) have been described. Patho-physiological bases of TLVDS remain poorly understood and its optimal management is until now empirical. Our aim was to characterize patho-physiological mechanisms of TLVDS by means of nuclear medicine procedures and to discuss the clinical usefulness of isotopic imaging for a non-invasive diagnosis of TLVDS.

METHODS AND RESULTS

During the sub acute phase, eighteen patients with TLVDS (13 TTC and 5 MVBS) underwent myocardial (99m)Tc-tetrofosmin or (201)Thallium Gated Single Photon Emission Computed Tomography (G-SPECT) (n=11), (123)I-mIBG SPECT (n=8) and (18)F-FDG Gated Positron Emission Tomography (G-PET) (n=15), assessing respectively LV perfusion, sympathetic innervation and glucose metabolism. Hypocontractile LV segments were characterized by normal perfusion but reduced uptake of (18)F-FDG and (123)I-mIBG. Topography and extent of metabolic defects and innervation abnormalities were largely overlapping. Follow-up (123)I-mIBG SPECT and (18)F-FDG G-PET were performed in selected patients showing rapid normalization of LV motion and progressive improvement of both glucose metabolism and sympathetic innervation.

DISCUSSION

With the hypothesis of neurogenic stunned myocardium as the central causative mechanism of TLVDS, (123)I-mIBG SPECT seems to be the most specific diagnostic technique. Sympathetic function and glucose metabolism seem to be strictly correlated in the hypocontractile LV segments. Finally, our results underline the role of nuclear imaging in the setting of patho-physiological mechanisms of TLVDS.

A new ECG criterion to identify takotsubo cardiomyopathy from anterior myocardial infarction: role of inferior leads

With the exception of contrast-enhanced cardiovascular magnetic resonance imaging, clear distinction of takotsubo cardiomyopathy from anterior wall myocardial infarction cannot be achieved currently by simple and noninvasive tests. The aim of this study was to examine the role of inferior ECG leads in distinguishing these two conditions. From January 2004 to June 2006, eight female patients suffering from takotsubo cardiomyopathy were identified by the Mayo Clinic criteria. The clinical and ECG features were compared with 27 consecutive sex- and age-matched patients with anterior wall myocardial infarction admitted to the Coronary Care Unit within the same period. The observed ECG features were then verified with that of 62 published cases of takotsubo cardiomyopathy. Takotsubo cardiomyopathy patients had similar left ventricular ejection fraction (35.0% +/- 5.7% vs 38.2% +/- 6.4%, P = 0.829), lower peak creatinine kinase level (461 +/- 330 U/l vs 2723 +/- 1826 U/l, P = 0.020), more ST-segment elevation in the inferior leads (50% vs 7.4%, P = 0.016), and virtually no ST-segment depression in inferior leads (0% vs 48.2%, P = 0.015) compared with patients who had anterior wall myocardial infarction. ST-segment elevation of >or=1.0 mm in lead II had 62.5% sensitivity and 92.6% specificity in detecting takotsubo cardiomyopathy. The observed ECG characteristics were comparable with those in the literature. In patients who present with anterior wall myocardial infarction, the absence of ST-segment depression or ST-segment elevation in inferior leads, especially if the ST-segment in lead II >or= III, is highly suggestive of takotsubo cardiomyopathy.

Takotsubo cardiomyopathy: state-of-the-art review

Takotsubo cardiomyopathy (TC) is characterized by transient, often severe, left ventricular dysfunction and electrocardiographic changes that might mimic acute myocardial infarction in the absence of significant obstructive coronary artery disease. It is often encountered in elderly women after physical or emotional stress. Excessive catecholamine stimulation, metabolic abnormalities, and microcirculatory dysfunction are thought to be responsible for the manifestations of this disorder. This comprehensive review summarizes relevant published data, atypical presentations, pathophysiology, and management strategy. It also includes a review of 789 patients with TC including nine illustrative cases encountered at our institution.

An unusual manifestation of Takotsubo cardiomyopathy

Takotsubo cardiomyopathy typically presents with chest pain, ST changes, and transient left ventricular apical ballooning in the absence of epicardial coronary artery disease. This process is reversible and usually benign. An unusual manifestation is that of left ventricular outflow tract obstruction with systolic anterior motion of the mitral valve. Recognition of this finding is critical in patient management especially in the setting of cardiogenic shock, as inotropes are likely to aggravate and worsen the clinical condition. We provide a systematic review and an illustrative case and discuss treatment strategies.

Takotsubo cardiomyopathy

Takotsubo cardiomyopathy, also known as stress-induced cardiomyopathy, left ventricular apical ballooning syndrome, and broken heart syndrome, is a clinical entity first described in the early 1990s in Japan and now receiving increased attention in the United States. The clinical features include an onset of chest pain mimicking that of an acute myocardial infarction, electrocardiogram changes similar to those of an acute myocardial infarction, normal coronary arteries on cardiac catheterization, and a signature appearance on echocardiogram. Takotsubo cardiomyopathy results in a significantly decreased ejection fraction that, as long as the patient receives appropriate hemodynamic support, typically undergoes spontaneous reversal. This article describes the history, clinical presentation, and management strategies for Takotsubo cardiomyopathy and provides a case study.

Takotsubo cardiomyopathy

Takotsubo cardiomyopathy is a disease in which patients present with signs and symptoms mimicking an acute coronary syndrome and, thus, undergo cardiac catheterization. At the time of catheterization, however, no critical coronary lesions are found. Most of these patients have a characteristic left ventriculogram and recent history of a preceding stressor. While the acute phase of the illness can lead to ventricular tachyarrhythmias and possibly even death, a key feature of this syndrome in the majority of patients is its generally benign course and reversibility in myocardial dysfunction over a period of days to weeks. The pathophysiology of Takotsubo cardiomyopathy remains unclear. Optimal long-term medical therapy has not been well established at this time, since the etiology of the disease process remains a source of debate.

Takotsubo cardiomyopathy: An under-recognized myocardial syndrome

Takotsubo cardiomyopathy is characterized by reversible left ventricular dysfunction with apical ballooning and is triggered by marked psychological or physiological stress in the absence of significant epicardial coronary artery disease. Clinically, this unique myocardial syndrome mimics acute myocardial infarction, and it has been considered to be a rare entity with a good prognosis. The literature on takotsubo cardiomyopathy is limited by selection bias and patient heterogeneity, but recent data suggest the syndrome is more prevalent, e.g., in critically ill, non-cardiac patients. Prompt diagnosis and aggressive therapy are essential for a rapid recovery. Clinicians should increase their awareness of this syndrome and more research should be carried out on the epidemiology, pathophysiology, and treatment of takotsubo cardiomyopathy.

Recurrence of Stress-Induced (Takotsubo) Cardiomyopathy

Takotsubo cardiomyopathy is a recently recognized form of transient left ventricular dysfunction that is presumably precipitated by stress and may clinically resemble an acute coronary syndrome. These patients have an akinetic left ventricular apex in an unusual shape that resembles a takotsubo. Although reports of single episodes of takotsubo cardiomyopathy are not infrequent in recent medical literature, we report a case of recurrence that may provide more insight into the nature of this syndrome.

Acute impairment of regional myocardial glucose uptake in the apical ballooning (takotsubo) syndrome

BACKGROUND

Apical ballooning syndrome (ABS) is a poorly understood clinical entity characterized by acute, transient systolic dysfunction of the left ventricular (LV) apex in the absence of epicardial coronary artery disease and commonly associated with acute emotional stress. We report abnormal regional myocardial perfusion and glucose uptake in 4 consecutive ABS patients studied using positron emission tomography with 13N-ammonia and 18F-fluorodeoxyglucose within 72 hours of presentation with ABS.

METHODS

All patients were postmenopausal females, 3 of whom had a major recent life stress event. Coronary angiography revealed no or minimal obstructive epicardial coronary artery disease. All patients exhibited reduced glucose uptake in the mid-LV and apical myocardial segments, which was out of proportion to perfusion abnormalities in half of the cases.

CONCLUSION

In all 4 patients, affected regions subsequently recovered regional LV systolic function within 6 weeks.

Acute impairment of regional myocardial glucose uptake in the apical ballooning (takotsubo) syndrome

BACKGROUND

Apical ballooning syndrome (ABS) is a poorly understood clinical entity characterized by acute, transient systolic dysfunction of the left ventricular (LV) apex in the absence of epicardial coronary artery disease and commonly associated with acute emotional stress. We report abnormal regional myocardial perfusion and glucose uptake in 4 consecutive ABS patients studied using positron emission tomography with 13N-ammonia and 18F-fluorodeoxyglucose within 72 hours of presentation with ABS.

METHODS

All patients were postmenopausal females, 3 of whom had a major recent life stress event. Coronary angiography revealed no or minimal obstructive epicardial coronary artery disease. All patients exhibited reduced glucose uptake in the mid-LV and apical myocardial segments, which was out of proportion to perfusion abnormalities in half of the cases.

CONCLUSION

In all 4 patients, affected regions subsequently recovered regional LV systolic function within 6 weeks.

Novel aspects of glypican glycobiology

Mutations in glypican genes cause dysmorphic and overgrowth syndromes in men and mice, abnormal development in flies and worms, and defective gastrulation in zebrafish and ascidians. All glypican core proteins share a characteristic pattern of 14 conserved cysteine residues. Upstream from the C-terminal membrane anchorage are 3-4 heparan sulfate attachment sites. Cysteines in glypican-1 can become nitrosylated by nitric oxide in a copper-dependent reaction. When glypican-1 is exposed to ascorbate, nitric oxide is released and participates in deaminative cleavage of heparan sulfate at sites where the glucosamines have a free amino group. This process takes place while glypican-1 recycles via a nonclassical, caveolin-1-associated route. Glypicans are involved in growth factor signalling and transport, e.g. of polyamines. Cargo can be unloaded from heparan sulfate by nitric oxide-dependent degradation. How glypican and its degradation products and the cargo exit from the recycling route is an enigma.