Estradiol protection against toxic effects of catecholamine on electrical properties in human-induced pluripotent stem cell derived cardiomyocytes

The Role of Catecholamines in the Pathogenesis of Diseases and the Modified Electrodes for Electrochemical Detection of Catecholamines: A Review

Catecholamines (CAs), which include adrenaline, noradrenaline, and dopamine, are neurotransmitters and hormones that critically regulate the cardiovascular system, metabolism, and stress response in the human body. The abnormal levels of these molecules can lead to the development of various diseases, including pheochromocytoma and paragangliomas, Alzheimer's disease, and Takotsubo cardiomyopathy. Due to their low cost, high sensitivity, flexible detection strategies, ease of integration, and miniaturization, electrochemical techniques have been extensively employed in the detection of CAs, surpassing traditional analytical methods. Electrochemical detection of CAs in real samples is challenging due to the tendency of poisoning electrode. Chemically modified electrodes have been widely used to solve the problems of poor sensitivity and selectivity faced by bare electrodes. There are a few articles that provide an overview of electrochemical detection and efficient enrichment of CAs, but there is a dearth of updates on the role of CAs in the pathogenesis of diseases. Additionally, there is still a lack of systematic synthesis with a focus on modified electrodes for electrochemical detection. Thus, this review provides a summary of the recent clinical pathogenesis of CAs and the modified electrodes for electrochemical detection of CAs published between 2017 and 2022. Moreover, challenges and future perspectives are also highlighted. This work is expected to provide useful guidance to researchers entering this interdisciplinary field, promoting further development of CAs pathogenesis, and developing more novel chemically modified electrodes for the detection of CAs.

Age-Related Differences in Takotsubo Syndrome: Results From the Multicenter GEIST Registry

BACKGROUND

The role of age in the short- and long-term prognosis of takotsubo syndrome (TTS) is controversial. The aim of the present study was to evaluate age-related differences and prognostic implications among patients with TTS.

METHODS AND RESULTS

In total, 2492 consecutive patients with TTS enrolled in an international registry were stratified into 4 groups (<45, 45-64, 65-74, and ≥75 years). The median long-term follow-up was 480 days (interquartile range, 83-1510 days). The primary outcome was all-cause mortality (in-hospital and out-of-hospital mortality). The secondary end point was TTS-related in-hospital complications. Among the 2479 patients, 58 (2.3%) were aged <45 years, 625 (25.1%) were aged 45 to 64 years, 733 (29.4%) were aged 65 to 74 years, and 1063 (42.6%) were aged ≥75 years. Young patients (<45 years) had a higher prevalence of men (from youngest to oldest, 24.1% versus 12.6% versus 9.7% versus 11.4%; P<0.01), physical triggers (46.6% versus 27.5%, 33.9%, and 38.4%; P<0.01), and non-apical forms of TTS (25.9% versus 23.7%, 12.7%, and 9%; P<0.01) than those aged 45 to 64, 65 to 74, and ≥75 years. During hospitalization, young patients experienced a higher rate of in-hospital complications (32.8% versus 23.4%, 27.4%, and 31.9%; P=0.01), but in-hospital mortality was higher in the older group (0%, 1.6%, 2.9%, and 5%; P=0.001). Long-term all-cause mortality was significantly higher in the older cohort (5.6%, 6.4%, 11.3%, and 22.3%; log-rank P<0.001), as was long-term cardiovascular mortality (0%, 0.9%, 1.9%, and 3.2%; log-rank P=0.01).

CONCLUSIONS

Young patients with TTS have a typical phenotype characterized by a higher prevalence of male sex, non-apical ballooning patterns, and in-hospital complications. However, in-hospital and long-term mortality are significantly lower in young patients with TTS.

REGISTRATION

URL: https://classic.clinicaltrials.gov/ct2/show/NCT04361994. Unique identifier: NCT04361994.

Triggers, characteristics, and hospital outcome of patients with Takotsubo syndrome: 10 years experience in a large university hospital centre

A unique clinical feature of Takotsubo syndrome (TTS) is the stress trigger factor. Different types of triggers exist, generally divided into emotional and physical stressor. The aim was to create long-term registry of all consecutive patients with TTS across all disciplines in our large university hospital. We enrolled patients on the basis of meeting the diagnostic criteria of the international InterTAK Registry. We aimed to determine type of triggers, clinical characteristics, and outcome of TTS patients during 10 years period. In our prospective, academic, single centre registry, we enrolled 155 consecutive patients with diagnoses of TTS between October 2013 and October 2022. The patients were divided into three groups, those having unknown (n = 32; 20.6%), emotional (n = 42; 27.1%), or physical (n = 81; 52.3%) triggers. Clinical characteristics, cardiac enzyme levels, echocardiographic findings, including ejection fraction, and TTS type did not differ among the groups. Chest pain was less common in the group of patients with a physical trigger. On the other hand, arrhythmogenic disorders such as prolonged QT intervals, cardiac arrest requiring defibrillation, and atrial fibrillation were more common among the TTS patients with unknown triggers compared with the other groups. The highest in-hospital mortality was observed between patients having physical trigger (16% vs. 3.1% in TTS with emotional trigger and 4.8% in TTS with unknown trigger; P = 0.060). Conclusion: More than half of the patients with TTS diagnosed in a large university hospital had a physical trigger as a stress factor. An essential part of caring for these types of patients is the correct identification of TTS in the context of severe other conditions and the absence of typical cardiac symptoms. Patients with physical trigger have a significantly higher risk of acute heart complications. Interdisciplinary cooperation is essential in the treatment of patients with this diagnosis.

An integrated strategy to explore the potential role of melatonin against copper-induced adrenaline toxicity in rat cardiomyocytes: Insights into oxidative stress, inflammation, and apoptosis

AIMS

Circumstantial anxiety as well as chronic stress may stimulate the release of stress hormones including catecholamines. Adrenaline toxicity has been implicated in many cardiovascular conditions. Considering previous literature that suggests the oxidative potential of the adrenaline-copper entity, we have investigated its potential nocuous role in isolated adult rat cardiomyocytes, the underlying molecular mechanism, and its possible protection by melatonin.

MAIN METHODS

Given the mechanistic congruity of adrenaline-copper (AC) with the well-established H₂O₂-copper-ascorbate (HCA) system of free radical generation, we have used the latter as a representative model to study the cytotoxic nature of AC. We further investigated the cardioprotective efficacy of melatonin in both the stress models through scanning electron microscopy, immunofluorescence, flow cytometry, and western blot analysis.

KEY FINDINGS

Results show that melatonin significantly protects AC-treated cardiomyocytes from ROS-mediated membrane damage, disruption of mitochondrial membrane potential, antioxidant imbalance, and distortion of cellular morphology. Melatonin protects cardiomyocytes from inflammation by downregulating pro-inflammatory mediators viz., COX-2, NF-κB, TNF-α, and upregulating anti-inflammatory IL-10. Melatonin significantly ameliorated cardiomyocyte apoptosis in AC and HCA-treated cells as evidenced by decreased BAX/BCL-2 ratio and subsequent suppression of caspase-9 and caspase-3 levels. The isothermal calorimetric study revealed that melatonin inhibits the binding of adrenaline bitartrate with copper in solution, which fairly explains the rescue potential of melatonin against AC-mediated toxicity in cardiomyocytes.

SIGNIFICANCE

Findings suggest that the multipronged strategy of melatonin that includes its antioxidant, anti-inflammatory, anti-apoptotic, and overall cardioprotective ability may substantiate its potential therapeutic efficacy against adrenaline-copper-induced damage and death of adult rat cardiomyocytes.

Takotsubo syndrome: getting closer to its causes

Takotsubo syndrome (TTS) accounts for between 1 and 4% of cases presenting clinically as an acute coronary syndrome. It typically presents as a transient cardiac phenotype of left ventricular dysfunction with spontaneous recovery. More dramatic presentations may include cardiogenic shock or cardiac arrest. Despite progress in the understanding of the condition since its first description in 1990, considerable questions remain into understanding underlying pathomechanisms. In this review article, we describe the current published data on potential underlying mechanisms associated with the onset of TTS including sympathetic nervous system over-stimulation, structural and functional alterations in the central nervous system, catecholamine secretion, alterations in the balance and distribution of adrenergic receptors, the additive impact of hormones including oestrogen, epicardial coronary or microvascular spasm, endothelial dysfunction, and genetics as potentially contributing to the cascade of events leading to the onset. These pathomechanisms provide suggestions for novel potential therapeutic strategies in patients with TTS including the role of cognitive behavioural therapy, beta-blockers, and endothelin-A antagonists. The underlying mechanism of TTS remains elusive. In reality, physical or emotional stressors likely trigger through the amygdala and hippocampus a central neurohumoral activation with the local and systemic secretion of excess catecholamine and other neurohormones, which exert its effect on the myocardium through a metabolic switch, altered cellular signalling, and endothelial dysfunction. These complex pathways exert a regional activation in the myocardium through the altered distribution of adrenoceptors and density of autonomic innervation as a protective mechanism from myocardial apoptosis. More research is needed to understand how these different complex mechanisms interact with each other to bring on the TTS phenotype.

Successful treatment of a severe Takotsubo syndrome case complicated by liver abscess

The main manifestations of Takotsubo syndrome (TTS) are a spherical expansion of the left ventricle or near the apex and decreased systolic function. TTS is mostly thought to be induced by emotional stress, and the induction of TTS by severe infection is not often reported. A 72-year-old female patient with liver abscess reported herein was admitted due to repeated fever with a history of hypertension and impaired glucose tolerance. Her severe infection caused TTS, and her blood pressure dropped to 80/40 mmHg. IABP treatment was performed immediately and continued for 10 days, and comprehensive medication was administered. Based on her disease course and her smooth recovery, general insights and learnings may be: Adding to mental and other pathological stress reaction, serious infections from pathogenic microorganism could be of great important causation of stress reaction leading to TTS, while basic diseases such as coronary heart disease, hypertension, and diabetes were be of promoting factors; In addition to effective drug therapies for TTS, the importance of the timely using of IABP should be emphasized.

Human induced pluripotent stem cell (hiPSC)-derived cardiomyocyte modelling of cardiovascular diseases for natural compound discovery

Cardiovascular disease (CVD) remains the leading cause of death worldwide. Natural compounds extracted from medicinal plants characterized by diverse biological activities and low toxicity or side effects, are increasingly taking center stage in the search for new drugs. Currently, preclinical evaluation of natural products relies mainly on the use of immortalized cell lines of human origin or animal models. Increasing evidence indicates that cardiomyopathy models based on immortalized cell lines do not recapitulate pathogenic phenotypes accurately and a substantial physiological discrepancy between animals and humans casts doubt on the clinical relevance of animal models for these studies. The newly developed human induced pluripotent stem cell (hiPSC) technology in combination with highly-efficient cardiomyocyte differentiation methods provides an ideal tool for modeling human cardiomyopathies in vitro. Screening of drugs, especially screening of natural products, based on these models has been widely used and has shown that evaluation in such models can recapitulate important aspects of the physiological properties of drugs. The purpose of this review is to provide information on the latest developments in this area of research and to help researchers perform screening of natural products using the hiPSC-CM platform.

Takotsubo syndrome: A current review of presentation, diagnosis, and management

Takotsubo syndrome is a syndrome of acute heart failure due to left ventricular systolic dysfunction that is associated with increased cardiovascular morbidity and mortality. It occurs in both sexes and at all ages, but predominates in post-menopausal women for reasons that are unclear. In a patient who presents with cardiac symptoms, electrocardiographic changes, and/or biomarker elevation indicating myocardial stress (i.e. troponin elevation), this condition should be considered in the differential diagnosis. Cardiac imaging is critical for a timely diagnosis of this condition and has management implications. This syndrome can occur with or without underlying coronary artery disease, and while there are various characteristic myocardial patterns described on imaging, the most common one is left ventricular dysfunction due to apical stunning with basal hyperkinesis. In the acute phase, Takotsubo syndrome can lead to life-threatening sequelae, including cardiogenic shock, pulmonary edema, thromboembolism, and arrhythmias. Multiple pathophysiologic mechanisms are implicated, including an acute increase in left ventricular afterload in the setting of sympathetic activation with a catecholamine storm, multi-vessel coronary vasospasm, coronary endothelial microvascular dysfunction, and inflammation. In this review, we discuss the current knowledge surrounding presentation, diagnosis, and treatment of this under-diagnosed condition.

Trigger related outcomes of takotsubo syndrome in a cancer population

Background

Takotsubo syndrome (TTS) occurs more frequently in cancer patients than in the general population, but the effect of specific TTS triggers on outcomes in cancer patients is not well studied.

Objectives

The study sought to determine whether triggering event (chemotherapy, immune-modulators vs. procedural or emotional stress) modifies outcomes in a cancer patient population with TTS.

Methods

All cancer patients presenting with acute coronary syndrome (ACS) between December 2008 and December 2020 at our institution were enrolled in the catheterization laboratory registry. Demographic and clinical data of the identified patients with TTS were retrospective collected and further classified according to the TTS trigger. The groups were compared with regards to major adverse cardiac events, overall survival and recovery of left ventricular ejection fraction (LVEF) and global longitudinal strain (GLS) after TTS presentation.

Results

Eighty one of the 373 cancer patients who presented with ACS met the Mayo criteria for TTS. The triggering event was determined to be "cancer specific triggers" (use of chemotherapy in 23, immunomodulators use in 7, and radiation in 4), and "traditional triggers" (medical triggers 22, and procedural 18 and emotional stress in 7). Of the 81 patients, 47 died, all from cancer-related causes (no cardiovascular mortality). Median survival was 11.9 months. Immunomodulator (IM) related TTS and radiation related TTS were associated with higher mortality during the follow-up. Patients with medical triggers showed the least recovery in LVEF and GLS while patients with emotional and chemotherapy triggers, showed the most improvement in LVEF and GLS, respectively.

Conclusion

Cancer patients presenting with ACS picture have a high prevalence of TTS due to presence of traditional and cancer specific triggers. Survival and improvement in left ventricular systolic function seem to be related to the initial trigger for TTS.

Hyperthermia as a trigger for Takotsubo syndrome in a rat model

Takotsubo syndrome is a well-characterized cause of acute yet reversible heart failure associated with periods of intense emotional stress, often mimicking on presentation an acute coronary syndrome. Animal models of Takotsubo syndrome have been developed, either through the application of a stressor, or administration of exogenous catecholamine. We found that in a model of isoproterenol-induced Takotsubo syndrome in anesthetized rats hyperthermia (40–41°C) would occur after the administration of isoproterenol. Maintenance of this hyperthermia would result in an apical hypocontractility typical of the syndrome, whereas prevention of hyperthermia with active cooling to maintain a euthermic core body temperature prevented (but did not subsequently reverse) apical hypocontractility. In vitro experimentation with isolated cardiomyocytes showed no effect of hyperthermia on either baseline contractility or contractility change after beta-adrenoceptor stimulation. We suggest that the rise in body temperature that is characteristic of catecholamine storm may be a component in the development of Takotsubo syndrome.

cAMP сoncentrations in cardiac mitochondria and serum in the С57ВL/6 mice under independent melanoma В16/F10 growth versus melanoma В16/F10 growth linked to chronic neurogenic pain

The aim of this research work is to study the cAMP level in the cardiac mitochondria and serum in the С57ВL/6 strain mice of both genders under the independent melanoma В16/F10 growth versus the melanoma В16/F10 growth linked to chronic neurogenic pain (CNP). Materials and methods. Mice of strain С57ВL/6 (n=336) have been grouped as follows: the intact group of the mice (♂n=21; ♀n=21), the reference group (♂n=21; ♀n=21) with the reproduced CNP model, the comparison group (♂n=63; ♀n=63) to include the mice with melanoma В16/F10, and the main test group (♂n=63; ♀n=63) to cover the mice with the melanoma growth against the CNP background. Upon expiration of 1 week, 2 and 3 weeks of the melanoma growth, in the animals of the above experimental groups the cardiac mitochondria have been isolated with the centrifugation using high-performance refrigerated centrifuge Avanti J-E, BECMAN COULTER, USA. With ELISA Kit (RayBio USA) we have determined cAMP concentrations in serum and in the cardiac mitochondria. Results. CNP has induced a decrease in the cAMP level in the cardiac mitochondria by a factor of 3,6 in the female mice only. In the animals of the comparison group the cAMP level in the heart has been increasing beginning with week 2 of the tumor growth on average by a factor of 4, while in the main test group starting from week 1 of the tumor growth it has been recorded 2-4 times higher and was depleted by the end of the experiment. As to the cAMP concentration in serum, the dynamics thereof has not been found to be in correlation with the cardiac mitochondrial data, and its concentration decrease has been recorded both in the females and the males. Conclusion. So, the changes in the cAMP concentration in the cardiac mitochondria demonstrate their gender-specific feature; the female mice as against the males have responded to an independent impact produced by CNP. As to the main test group, CNP has stimulated an increase in the cAMP level in the cardiac mitochondria 1 week earlier than it is the case with the comparison group, and it has resulted in the full cAMP depletion by the 3rd week of the experiment.

Arrhythmias and Their Electrophysiological Mechanisms in Takotsubo Syndrome: A Narrative Review

BACKGROUND

Takotsubo syndrome (TTS), an acute and usually reversible condition, is associated with both tachy- and bradyarrhythmias. Such arrhythmias can be life-threatening, e.g. ventricular tachycardia and fibrillation, and associated with cardiac arrest. Others, such as atrioventricular block, persist and require long-term device therapy. In this narrative review, we aim to provide a summary of the current literature on arrhythmias in TTS and their clinical sequelae.

METHODS

PubMed and Medline databases were searched with various permutations of TTS, arrhythmias and beta-adrenoceptors. After application of exclusion criteria and review, 84 articles were included.

RESULTS

Although there are no specific electrocardiograph (ECG) findings in TTS to differentiate it from ST-elevation myocardial infarction, suggestive patterns include small QRS amplitude, ST segment elevation without reciprocal ST depression and prolonged QT interval. Atrial tachyarrhythmias (incidence of 5-15%) are associated with a more unwell patient cohort. Ventricular arrhythmias (incidence 4-14%) are often associated with prolonged QT interval and are a cause of sudden death in TTS. Bradyarrhythmias are less common (incidence 1.3-2.5%), but have been reported with TTS, and usually persist beyond the acute phase.

CONCLUSIONS

Takotsubo syndrome, though considered primarily a disease of the myocardium, carries multiple arrhythmic manifestations that affect short- and long-term prognosis. The management of such arrhythmias represents a constantly evolving area of research.

Update of Takotsubo cardiomyopathy: Present experience and outlook for the future

Takotsubo cardiomyopathy (TTS) has become a recognised clinical entity since the Japanese scientist Sato first described it in 1990.

Despite an increasing number of confirmed cases, especially during the COVID-19 pandemic, its pathophysiology remains incompletely understood, and decision-making differs in the diagnosis and treatment. In addition, it is not evident whether a significant increase in TTS is due to better understanding among practitioners and widespread access to coronary angiography, or if it is a reflection of an actual increase in incidence.

We analysed a series of international research studies from 1990 to 2021. Beyond epidemiology and clinical presentation, we evaluated and summarised fundamental knowledge about various predisposing factors, with particular attention to the iatrogenic impact of certain drugs, namely antidepressants, chemotherapy, and antiarrhythmics.

Furthermore, we highlighted the main pathophysiological theories to date. In addition, based on published studies and clinical cases, we investigated the role of numerous diagnostic approaches in the differential diagnosis of TTS and identified predictors of TTS complications, such as cardiogenic shock, ventricular fibrillation, and left ventricular thrombi. Accordingly, we sought to propose a diagnostic algorithm and further treatment management of TTS under the presence of possible complications to help practitioners make more informed decisions, as the initial presentation continues to pose a challenge due to its close similarity to acute coronary syndrome with ST-elevation.

In conclusion, this article examines Takotsubo cardiomyopathy from different perspectives and, along with future systematic reviews and meta-analyses, can be of particular interest to practising cardiologists and researchers in developing clinical guidelines.

Case Report: Takotsubo Syndrome Induced by Severe Anaphylactic Reaction During Anesthesia Induction and Subsequent High-Dose Epinephrine Resuscitation

Takotsubo syndrome (TTS) is a type of non-ischemic cardiomyopathy characterized by an acute reversible left ventricular dysfunction with typical apical ballooning, usually with subsequent complete recovery. Early diagnosis and prompt treatment are of great essence. Herein, we described a case of TTS of a patient who was scheduled initially for laparoscopic endometrial cancer staging. The 69-year-old woman presented with cardiogenic shock induced by the severe anaphylactic reaction to the antibiotics during anesthesia induction. Cardiopulmonary resuscitation (CPR) was implemented while several boluses of 1 mg epinephrine were injected. After the return of spontaneous circulation, a large number of orange peel-like rash appeared on the head, face, neck, and trunk of the patient. Transesophageal echocardiography (TEE) revealed diffused decreased left ventricular systolic function. Therefore, veno-arterial extracorporeal membrane oxygenation (VA-ECMO) and intra-aortic balloon pump (IABP) were applied in the intensive care unit. Biomarkers like cardiac troponin I (cTnI) subsequently decreased with improved cardiac insufficiency. Finally, the patient was discharged in good condition. This case demonstrated that TTS could be secondary to severe anaphylactic shock and exogenous catecholamines. With the consideration of the reversible condition and predictable recovery of TTS, early vigilance and advanced life support devices should be necessary.

A Case Series of Concomitant Cardiac Electrical Disease among Takotsubo Syndrome Patients and Literature Review

The pathophysiology of Takotsubo Syndrome (TTS) is not completely understood and the trigger of sudden cardiac death (SCD) in TTS is not clear either. We therefore sought to find an association between TTS and primary electrical diseases. A total of 148 TTS patients were analyzed between 2003 and 2017 in a bi-centric manner. Additionally, a literature review was performed. The patients were included in an ongoing retrospective cohort database. The coexistence of TTS and primary electrical diseases was confirmed in five cases as the following: catecholaminergic polymorphic ventricular tachycardia (CPVT, 18-year-old female) (n = 1), LQTS 1 (72-year-old female and 65-year-old female) (n = 2), LQTS 2 (17-year-old female) (n = 1), and LQTS in the absence of mutations (22-year-old female). Four patients suffered from malignant tachyarrhythmia and recurrent syncope after TTS. Except for the CPVT patient and one LQTS 1 patient, all other cases underwent subcutaneous ICD implantation. An event recorder of the CPVT patient after starting beta-blocker did not detect arrhythmias. The diagnosis of primary electrical disease was in 80% of cases unmasked on a TTS event. This diagnosis triggered a family clinical and genetic screening confirming the diagnosis of primary electrical disease. A subsequent literature review identified five cases as the following: a congenital atrioventricular block (n = 1), a Jervell and Lange-Nielsen Syndrome (n = 1), and a family LQTS in the absence of a mutation (n = 2), LQTS 2 (n = 1). A primary electrical disease should be suspected in young and old TTS patients with a family history of sudden cardiac death. In suspected cases, e.g., ongoing QT interval prolongation, despite recovery of left ventricular ejection fraction a family screening is recommended.

Glucose Counteracts Isoprenaline Effects on Ion Channel Functions in Human-Induced Pluripotent Stem Cell-Derived Cardiomyocytes

Recent studies indicate that the disorder of glucose metabolism in myocardial tissue is involved in the development of Takotsubo syndrome (TTS). This study investigated the effects of a high level of glucose on the pathogenesis of TTS, focusing on the electrophysiological mechanisms. Human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) were treated with toxic concentration of isoprenaline (Iso, 1 mM) and a high level of glucose (22 mM) to mimic the setting of TTS and diabetes mellitus (DM). Iso prolonged action potential duration (APD) through enhancing the late sodium channel current and suppressing the transient outward potassium current (Ito). However, a high level of glucose prevented the APD prolongation and the change in Ito. High-level glucose reduced the expression levels of PI3K/Akt, β1-adrenoceptors, Gs-protein, and PKA, suggesting their involvement in the protective effects of high-level glucose against toxic effects of catecholamine. High glucose level did not influence Iso-induced ROS-generation, suggesting that the protective effects of high-level glucose against Iso did not result from changes in ROS generation. High-level glucose may protect cardiomyocytes from the toxic effects of catecholamine excess through suppressing β1-adrenoceptor-Gs-PKA signaling. DM may reduce the risk for occurrence of arrhythmias due to QT prolongation in TTS patients.

Takotsubo Syndrome: Translational Implications and Pathomechanisms

Takotsubo syndrome (TTS) is identified as an acute severe ventricular systolic dysfunction, which is usually characterized by reversible and transient akinesia of walls of the ventricle in the absence of a significant obstructive coronary artery disease (CAD). Patients present with chest pain, ST-segment elevation or ischemia signs on ECG and increased troponin, similar to myocardial infarction. Currently, the known mechanisms associated with the development of TTS include elevated levels of circulating plasma catecholamines and their metabolites, coronary microvascular dysfunction, sympathetic hyperexcitability, inflammation, estrogen deficiency, spasm of the epicardial coronary vessels, genetic predisposition and thyroidal dysfunction. However, the real etiologic link remains unclear and seems to be multifactorial. Currently, the elusive pathogenesis of TTS and the lack of optimal treatment leads to the necessity of the application of experimental models or platforms for studying TTS. Excessive catecholamines can cause weakened ventricular wall motion at the apex and increased basal motion due to the apicobasal adrenoceptor gradient. The use of beta-blockers does not seem to impact the outcome of TTS patients, suggesting that signaling other than the beta-adrenoceptor-associated pathway is also involved and that the pathogenesis may be more complex than it was expected. Herein, we review the pathophysiological mechanisms related to TTS; preclinical TTS models and platforms such as animal models, human-induced pluripotent stem cell-derived cardiomyocyte (hiPSC-CM) models and their usefulness for TTS studies, including exploring and improving the understanding of the pathomechanism of the disease. This might be helpful to provide novel insights on the exact pathophysiological mechanisms and may offer more information for experimental and clinical research on TTS.

Dopamine D1/D5 Receptor Signaling Is Involved in Arrhythmogenesis in the Setting of Takotsubo Cardiomyopathy

Background

Previous studies suggested involvement of non-ß-adrenoceptors in the pathogenesis of Takotsubo cardiomyopathy (TTC). This study was designed to explore possible roles and underlying mechanisms of dopamine D1/D5 receptor coupled signaling in arrhythmogenesis of TTC.

Methods

Human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) were challenged by toxic concentration of epinephrine (Epi, 0.5 mM for 1 h) for mimicking the catecholamine excess in setting of TTC. Specific receptor blockers and activators were used to unveil roles of D1/D5 receptors. Patch clamp, qPCR, and FACS analyses were performed in the study.

Results

High concentration Epi and two dopamine D1/D5 receptor agonists [(±)-SKF 38393 and fenoldopam] reduced the depolarization velocity and prolonged the duration of action potentials (APs) and caused arrhythmic events in iPSC-CMs, suggesting involvement of dopamine D1/D5 receptor signaling in arrhythmogenesis associated with QT interval prolongation in the setting of TTC. (±)-SKF 38393 and fenoldopam enhanced the reactive oxygen species (ROS)-production. H₂O₂ (100 μM) recapitulated the effects of (±)-SKF 38393 and fenoldopam on APs and a ROS-blocker N-acetylcysteine (NAC, 1 mM) abolished the effects, suggesting that the ROS-signaling is involved in the dopamine D1/D5 receptor actions. A NADPH oxidases blocker and a PKA- or PKC-blocker suppressed the effects of the dopamine receptor agonist, implying that PKA, NADPH oxidases and PKC participated in dopamine D1/D5 receptor signaling. The abnormal APs resulted from dopamine D1/D5 receptor activation-induced dysfunctions of ion channels including the Na⁺ and L-type Ca²⁺ and I_Kr channels.

Conclusions

Dopamine D1/D5 receptor signaling plays important roles for arrhythmogenesis of TTC. Dopamine D1/D5 receptor signaling in cardiomyocytes might be a potential target for treating arrhythmias in patients with TTC.

Oestrogenic Regulation of Mitochondrial Dynamics

Biological sex influences disease development and progression. The steroid hormone 17β-oestradiol (E2), along with its receptors, is expected to play a major role in the manifestation of sex differences. E2 exerts pleiotropic effects in a system-specific manner. Mitochondria are one of the central targets of E2, and their biogenesis and respiration are known to be modulated by E2. More recently, it has become apparent that E2 also regulates mitochondrial fusion–fission dynamics, thereby affecting cellular metabolism. The aim of this article is to discuss the regulatory pathways by which E2 orchestrates the activity of several components of mitochondrial dynamics in the cardiovascular and nervous systems in health and disease. We conclude that E2 regulates mitochondrial dynamics to maintain the mitochondrial network promoting mitochondrial fusion and attenuating mitochondrial fission in both the cardiovascular and nervous systems.

Stepwise approach for diagnosis and management of Takotsubo syndrome with cardiac imaging tools

Takotsubo syndrome is featured by transient left ventricle dysfunction in the absence of significant coronary artery disease, mainly triggered by emotional or physical stress. Its clinical presentation is similar to acute coronary syndrome; therefore, cardiac imaging tools have a crucial role. Coronary angiography is mandatory for exclusion of pathological stenosis. On the other side, transthoracic echocardiography is the first non-invasive imaging modality for an early evaluation of left ventricle systolic and diastolic function. Left ventricle morphologic patterns could be identified according to the localization of wall motion abnormalities. Moreover, an early identification of potential mechanical and electrical complications such as left ventricle outflow tract obstruction, mitral regurgitation, thrombus formation, right ventricular involvement, cardiac rupture, and cardiac rhythm disorders could provide additional information for clinical management and therapy. Because of the dynamic evolution of the syndrome, comprehensive serial echocardiographic examinations should be systematically performed. Advanced techniques, including speckle-tracking echocardiography, cardiac magnetic resonance, and nuclear imaging can provide mechanistic and pathophysiologic insights into this syndrome. This review focuses on these aspects and provide a stepwise approach of all cardiac imaging tools for the diagnosis and the management of Takotsubo syndrome.

Risk Factors for Cardiac Complications in Patients With Pheochromocytoma and Paraganglioma: A Retrospective Single-Center Study

BACKGROUND

Catecholamine excess arising from pheochromocytomas and paragangliomas (PPGLs) can cause a wide spectrum of cardiac manifestations. Although there are reviews of reported cases, these reviews lack detailed data, which makes it impossible to perform an accurate analysis. In this study, we conducted a comprehensive analysis of cardiovascular complications (CCs), including PPGL-related myocardial injury, cardiogenic shock, and arrhythmias requiring antiarrhythmic therapy, in a large cohort of patients with PPGL.

METHODS

We retrospectively analyzed the clinical data of consecutive patients with PPGL admitted between January 2018 and June 2020. The prevalence and the characteristics of patients with CCs were investigated. Moreover, comparisons were made between patients with and without CCs.

RESULTS

Compared with the non-CC group, the percentage of men was significantly lower (14/41 vs.92/175, 34.1% vs. 52.6%, p = 0.034) and the proportion of patients with paroxysmal hypertension was significantly higher (13/41 vs.29/173, 31.7% vs.16.8%, p = 0.03) in the CC group. More patients showed excessive sweating (19/41 vs 64/175, 46.3% vs. 24.0%, p = 0.004) and PPGL crisis (7/41 vs. 10/175, 17.1% vs.5.7%, p=0.035) in the CC group. In terms of laboratory findings, higher white blood cell [7.36 (6.49, 20.23) vs. 5.95 (5.1, 6.97)×10⁹/L, p<0.001] and platelet [339.28 ± 108.54 vs. 250.66 ± 70.83(×10⁹/L), p = 0.021] counts were more common in the CC group. There was also a higher prevalence of combination-producing PPGL in the CC group (13/24 vs.20/149, 54.2% vs.13.4%, p<0.001). However, the tumor size, invasive behavior on histology, and hemorrhage or necrosis on histology did not differ between the two groups. Platelet count [odds ratio (OR): 1.009; 95% confidence interval (CI) 1.001-1.016; p=0.023] and combination-secreting PPGL (OR: 5.009; 95% CI 1.365-18.38; p=0.015) are independent risk factors for CCs in patients with PPGL.

CONCLUSIONS

In patients with PPGL, even in the absence of signs and symptoms of CCs, a work up of cardiology should be strongly considered. Importantly, if patients with PPGLs have higher platelet counts and the combination-secreting pattern, they are more likely to have CCs. Thus, a careful cardiac evaluation should be performed.

Pathophysiology of Takotsubo syndrome - a joint scientific statement from the Heart Failure Association Takotsubo Syndrome Study Group and Myocardial Function Working Group of the European Society of Cardiology - Part 2: vascular pathophysiology, gender and sex hormones, genetics, chronic cardiovascular problems and clinical implications

While the first part of the scientific statement on the pathophysiology of Takotsubo syndrome was focused on catecholamines and the sympathetic nervous system, in the second part we focus on the vascular pathophysiology including coronary and systemic vascular responses, the role of the central and peripheral nervous systems during the acute phase and abnormalities in the subacute phase, the gender differences and integrated effects of sex hormones, genetics of Takotsubo syndrome including insights from microRNA studies and inducible pluripotent stem cell models of Takotsubo syndrome. We then discuss the chronic abnormalities of cardiovascular physiology in survivors, the limitations of current clinical and preclinical studies, the implications of the knowledge of pathophysiology for clinical management and future perspectives and directions of research.

Reproductive History in Takotsubo Syndrome, A Register-Based Cohort Study

Background: Takotsubo syndrome (TS) is a recently recognized serious heart condition that mainly affects women. Despite that 80–90% of the patients are women, few studies have focused on sex-specific characteristics such as female sex hormones and reproductive history. The aim of the study was to compare reproductive history in patients with TS with controls.

Methods: This register-based cohort study compared reproductive history and off-spring birth characteristics between 158 TS patients without coronary artery stenoses and 236 age- and sex-matched controls (C) with coronary artery stenoses because of acute coronary syndrome (ACS-C), respectively, 285 without coronary artery stenoses with chest pain (CP-C).

Results: There were no differences in pregnancy complications between TS and CP-C. Gestational length did not differ, but infants born to TS patients had lower birth weight for gestational age than CP-C with an odds ratio of 1.7 (95% confidence interval 1.2–2.5) for infants born small.

Conclusion: The results showing an association between birth weight for gestational age and TS later in life are hypothesis-generating. The association is not likely causal and before delivery of small for gestational age infants can be considered as a risk marker for TS later in life the results need to be confirmed in independent studies

Alpha 1-adrenoceptor signalling contributes to toxic effects of catecholamine on electrical properties in cardiomyocytes

AIMS

This study aimed to investigate possible roles and underlying mechanisms of alpha-adrenoceptor coupled signalling for the pathogenesis of Takotsubo syndrome (TTS).

METHODS AND RESULTS

Human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) were treated with a toxic concentration of epinephrine (Epi, 0.5 mM for 1 h) to mimic the setting of TTS. Patch-clamp technique, polymerase chain reaction (PCR) and Fluorescence-activated cell sorting (FACS) were employed for the study. High concentration Epi suppressed the depolarization velocity, prolonged duration of action potentials and induced arrhythmic events in hiPSC-CMs. The Epi effects were attenuated by an alpha-adrenoceptor blocker (phentolamine), suggesting involvement of alpha-adrenoceptor signalling in arrhythmogenesis related to QT interval prolongation in the setting of TTS. An alpha 1-adrenoceptor agonist (phenylephrine) but not an alpha 2-adrenoceptor agonist (clonidine) mimicked Epi effects. Epi enhanced ROS production, which could be attenuated by the alpha- adrenoceptor blocker. Treatment of cells with H2O2 (100 µM) mimicked the effects of Epi on action potentials and a reactive oxygen species (ROS)-blocker (N-acetyl-I-cysteine, 1 mM) prevented the Epi effects, indicating that the ROS signalling is involved in the alpha-adrenoceptor actions. Nicotinamide adenine dinucleotide phosphate hydrogen (NADPH) oxidases were involved in alpha 1-adrenoceptor signalling. A protein kinase C (PKC) blocker suppressed the effects of Epi, phenylephrine and ROS as well, implying that PKC participated in alpha 1-adrenoceptor signalling and acted as a downstream factor of ROS. The abnormal action potentials resulted from alpha 1-adrenoceptor activation-induced dysfunctions of ion channels including the voltage-dependent Na+ and L-type Ca2+ channels.

CONCLUSIONS

Alpha 1-adrenoceptor signalling plays important roles for arrhythmogenesis of TTS. Alpha-adrenoceptor blockers might be clinically helpful for treating arrhythmias in patients with TTS.

Impact of Atrial Fibrillation on Outcome in Takotsubo Syndrome: Data From the International Takotsubo Registry

Background

Atrial fibrillation (AF) is a major risk factor for mortality. The prevalence, clinical correlates, and prognostic impact of AF in Takotsubo syndrome (TTS) have not yet been investigated in a large patient cohort. This study aimed to investigate the prevalence, clinical correlates, and prognostic impact of AF in patients with TTS.

Methods and Results

Patients with TTS were enrolled from the International Takotsubo Registry, which is a multinational network with 26 participating centers in Europe and the United States. Patients were dichotomized according to the presence or absence of AF at the time of admission. Of 1584 patients with TTS, 112 (7.1%) had AF. The mean age was higher (P<0.001), and there were fewer women (P=0.046) in the AF than in the non‐AF group. Left ventricular ejection fraction was significantly lower (P=0.001), and cardiogenic shock was more often observed (P<0.001) in the AF group. Both in‐hospital (P<0.001) and long‐term mortality (P<0.001) were higher in the AF group. Multivariable Cox regression analysis revealed that AF was independently associated with higher long‐term mortality (hazard ratio, 2.31; 95% CI, 1.50–3.55; P<0.001). Among patients with AF on admission, 42% had no known history of AF before the acute TTS event, and such patients had comparable in‐hospital and long‐term outcomes compared with those with a history of AF.

Conclusions

In patients presenting with TTS, AF on admission is significantly associated with increased in‐hospital and long‐term mortality rates. Whether antiarrhythmics and/or cardioversion are beneficial in TTS with AF should thus be tested in a future trial.

Registration

URL: https://www.clinicaltrials.gov; Unique identifier: NCT01947621.

TRPV1 activation and internalization is part of the LPS-induced inflammation in human iPSC-derived cardiomyocytes

The non-selective cation channel transient receptor potential vanilloid 1 (TRPV1) is expressed throughout the cardiovascular system. Recent evidence shows a role for TRPV1 in inflammatory processes. The role of TRPV1 for myocardial inflammation has not been established yet. Human induced pluripotent stem cell (iPSC)-derived cardiomyocytes (hiPSC-CM) from 4 healthy donors were incubated with lipopolysaccharides (LPS, 6 h), TRPV1 agonist capsaicin (CAP, 20 min) or the antagonist capsazepine (CPZ, 20 min). TRPV1 expression was studied by PCR and western blotting. TRPV1 internalization was analyzed by immunofluorescence. Interleukin-6 (IL-6) secretion and phosphorylation of JNK, p38 and ERK were determined by ELISA. TRPV1-associated ion channel current was measured by patch clamp. TRPV1-mRNA and -protein were expressed in hiPSC-CM. TRPV1 was localized in the plasma membrane. LPS significantly increased secretion of IL-6 by 2.3-fold, which was prevented by pre-incubation with CPZ. LPS induced TRPV1 internalization. Phosphorylation levels of ERK, p38 or JNK were not altered by TRPV1 stimulation or inhibition. LPS and IL-6 significantly lowered TRPV1-mediated ion channel current. TRPV1 mediates the LPS-induced inflammation in cardiomyocytes, associated with changes of cellular electrophysiology. LPS-induced inflammation results in TRPV1 internalization. Further studies have to examine the underlying pathways and the clinical relevance of these findings.

Incidence and Clinical Impact of Right Ventricular Involvement (Biventricular Ballooning) in Takotsubo Syndrome: Results From the GEIST Registry

BACKGROUND

The short- and long-term prognosis of Takotsubo syndrome (TTS) presenting with right ventricular (RV) involvement remains poorly understood.

RESEARCH QUESTION

What is the incidence and clinical outcome of RV involvement in TTS?

STUDY DESIGN AND METHODS

This study analyzed 839 consecutive patients with TTS (758 female subjects and 81 male subjects) in a multicenter registry. RV involvement was defined as wall motion abnormality of the RV free wall, with or without apical involvement. The median long-term follow-up was 2.1 years (interquartile range, 0.3-4.5 years). The primary outcome was in-hospital and out-of-hospital all-cause mortality. The secondary end point was a composite of in-hospital death, thromboembolic events, cardiogenic shock, pulmonary edema, and malignant arrhythmias.

RESULTS

The incidence of RV involvement in TTS was 11% (n = 93). More often patients with RV involvement were male compared with patients without RV involvement (P = .02). There was a slight difference in the left ventricular ejection fraction measured in patients with RV involvement vs those patients with isolated left ventricular TTS (38 ± 10% vs 40 ± 10%; P = .03). No major differences in terms of comorbidities were observed between groups except regarding a history of cancer, which was significantly more prevalent in patients with TTS presenting with RV involvement (P = .03). Physical stressors were more prevalent in the RV group (P < .01), whereas emotional stressors were less prevalent (P < .01). Patients with RV involvement had a higher incidence of in-hospital cardiogenic shock (P = .02). The primary outcome (in- and out-of-hospital all-cause mortality) was observed in 12.8% of patients without RV involvement compared with 29% of patients with RV involvement. Although the in-hospital mortality rate was similar in both groups, a higher out-of-hospital all-cause mortality rate (log-rank test, P = .008) was observed in the RV involvement group. The Cox multivariable regression analysis showed that physical triggers were independent predictors of RV involvement.

INTERPRETATION

RV involvement defines a high-risk cohort of patients with TTS.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov; No.: NCT04361994; URL: www.clinicaltrials.gov.

Effects of Antiarrhythmic Drugs on hERG Gating in Human-Induced Pluripotent Stem Cell-Derived Cardiomyocytes From a Patient With Short QT Syndrome Type 1

Aims: The short QT syndrome type 1 (SQT1) is linked to hERG channel mutations (e.g., N588K). Drug effects on hERG channel gating kinetics in SQT1-cells have not been investigated. Methods: This study used hiPSC-CMs of a healthy donor and a SQT1-patient carrying the N588K mutation and patch clamp to examine the drug effects on hERG channel gating kinetics. Results: Ajmaline, amiodarone, ivabradine, flecainide, quinidine, mexiletine and ranolazine inhibited the hERG channel current (I_Kr) less strongly in hiPSC-CMs from the SQTS1-patient (SQT1-hiPSC-CMs) comparing with cells from the healthy donor (donor-hiPSC-CMs). Quinidine and mexiletine reduced, but ajmaline, amiodarone, ivabradine and ranolazine increased the time to peak of I_Kr similarly in SQT1-hiPSC-CMs and donor-hiPSC-CMs. Although regarding the shift of activation and inactivation curves, tested drugs showed differential effects in donor- and SQT1-hiPSC-CMs, quinidine, ajmaline, ivabradine and mexiletine but not amiodarone, flecainide and ranolazine reduced the window current in SQT1-hiPSC-CMs. Quinidine, ajmaline, ivabradine and mexiletine differentially changed the time constant of recovery from inactivation, but all of them increased the time constant of deactivation in SQT1-hiPSC-CMs. Conclusion: The window current-reducing and deactivation-slowing effects may be important for the antiarrhythmic effect of ajmaline, ivabradine, quinidine and mexiletine in SQT1-cells. This information may be helpful for selecting drugs for treating SQT1-patients with hERG channel mutation.

Pathophysiology of Takotsubo Syndrome: JACC State-of-the-Art Review

Takotsubo syndrome (TTS) has been a recognized clinical entity for 31 years, since its first description in 1990. TTS is now routinely diagnosed in patients who present with acute chest pain, electrocardiographic changes, troponin elevation, unobstructed coronary arteries, and a typical pattern of circumferential left ventricular wall motion abnormalities that usually involve the apical and midventricular myocardium. Increasing understanding of this intriguing syndrome stems from wider recognition, possible increasing frequency, and a rising number of publications focused on the pathophysiology in clinical and laboratory studies. A comprehensive understanding of TTS pathophysiology and evidence-based treatments are lacking, and specific and effective treatments are urgently required. This paper reviews the pathophysiology of this fascinating syndrome; what is known from both clinical and preclinical studies, including review of the evidence for microvascular dysfunction, myocardial beta-adrenergic signaling, inflammation, and electrophysiology; and where focused research needs to fill gaps in understanding TTS.

The Link Between Sex Hormones and Susceptibility to Cardiac Arrhythmias: From Molecular Basis to Clinical Implications

It is well-known that gender is an independent risk factor for some types of cardiac arrhythmias. For example, males have a greater prevalence of atrial fibrillation and the Brugada Syndrome. In contrast, females are at increased risk for the Long QT Syndrome. However, the underlying mechanisms of these gender differences have not been fully identified. Recently, there has been accumulating evidence indicating that sex hormones may have a significant impact on the cardiac rhythm. In this review, we describe in-depth the molecular interactions between sex hormones and the cardiac ion channels, as well as the clinical implications of these interactions on the cardiac conduction system, in order to understand the link between these hormones and the susceptibility to arrhythmias.

Physiological And Pathological Roles Of Protein Kinase A In The Heart

Protein kinase A (PKA) is a central regulator of cardiac performance and morphology. Myocardial PKA activation is induced by a variety of hormones, neurotransmitters and stress signals, most notably catecholamines secreted by the sympathetic nervous system. Catecholamines bind β-adrenergic receptors to stimulate cAMP-dependent PKA activation in cardiomyocytes. Elevated PKA activity enhances Ca2+ cycling and increases cardiac muscle contractility. Dynamic control of PKA is essential for cardiac homeostasis, as dysregulation of PKA signaling is associated with a broad range of heart diseases. Specifically, abnormal PKA activation or inactivation contributes to the pathogenesis of myocardial ischemia, hypertrophy, heart failure, as well as diabetic, takotsubo, or anthracycline cardiomyopathies. PKA may also determine sex-dependent differences in contractile function and heart disease predisposition. Here, we describe the recent advances regarding the roles of PKA in cardiac physiology and pathology, highlighting previous study limitations and future research directions. Moreover, we discuss the therapeutic strategies and molecular mechanisms associated with cardiac PKA biology. In summary, PKA could serve as a promising drug target for cardioprotection. Depending on disease types and mechanisms, therapeutic intervention may require either inhibition or activation of PKA. Therefore, specific PKA inhibitors or activators may represent valuable drug candidates for the treatment of heart diseases.

Takotsubo Endocrinopathy

Takotsubo cardiomyopathy (TCMP) is a cardiac disorder, often seen in post-menopausal women, that resembles an acute coronary syndrome in its clinical presentation. The aetiopathogenesis of TCMP may have an endocrine basis, and hence we believe the term 'takotsubo endocrinopathy' may be more appropriate. In this review, we describe the various endocrine disorders that may lead to TCMP. We also describe the pathogenetic mechanism by which these endocrine disorders may lead to TCMP. Cardiomyopathy associated with pheochromocytoma closely resembles TCMP and we have suggested that it must be ruled out in all patients presenting with TCMP. The role of oestrogen deficiency in the pathogenesis of TCMP is examined in this article. The importance of the involvement of an endocrinologist in the management of TCMP is emphasised.

Reversible exercise-induced left ventricular dysfunction in symptomatic patients with previous Takotsubo syndrome: insights from stress echocardiography

AIMS

Takotsubo syndrome (TTS) is usually associated with rapid and spontaneous recovery of left ventricular (LV) function. However, a proportion of patients may have persistent symptoms. This study aimed to determine the haemodynamic and LV contractile responses to exercise in these patients.

METHODS AND RESULTS

Thirty symptomatic TTS patients referred for exercise echocardiography, a median of 15 months following the index TTS episode, were matched with 30 controls with normal exercise echocardiography. Beta-blockers were withheld prior to the test. LV volumes, ejection fraction (EF) and wall motion score index (WMSI), were measured at rest and stress. The TTS cohort were Caucasian women with mean age of 64.6 ± 7.4 years and similar coronary risk factor profile and EF to controls. Resting systolic blood pressure (SBP), LV end-diastolic volume, wall stress, and right ventricular fractional area change were higher in TTS patients compared with controls. Stress echo data showed similar exercise time, peak heart rate, and peak SBP in TTS patients vs. controls, but TTS patients had higher LV volumes, lower exercise LVEF (70 ± 10% vs. 78 ± 7%; P = 0.001), ΔLVEF (4 ± 8% vs. 12 ± 5%; P < 0.001), and WMSI (1.4 ± 0.4 vs. 1 ± 0; P < 0.001) compared with controls. Twenty TTS patients had clear exercise-induced wall motion abnormalities, mainly involving the apex or more globally, with a mean ΔLVEF of 1% compared with 12% in controls. Among the other 10 TTS patients, the ΔLVEF was 10%.

CONCLUSION

Symptomatic patients with previous TTS have a blunted contractile response to exercise. The therapeutic and prognostic implications of these findings need further investigation.

Chromogranin-A serum levels in patients with takotsubo syndrome and ST elevation acute myocardial infarction

BACKGROUND

Sympathergic hyperactivity is considered one of the main trigger precipitating takotsubo syndrome (TTS). Chromogranin-A (CgA), a prognostic biomarker of sympatho-adrenal activation, is markedly high in acute coronary syndrome (ACS) and heart failure (HF), but its role in TTS is unknown.

METHODS

CgA serum levels from patients with TTS and symptoms onset <24 hours were consecutively evaluated and compared with anterior ST-elevation myocardial infarction (STEMI) patients from November 2016 to December 2019. Short and long-term follow-up data were recorded.

RESULTS

Eleven women with TTS and 10 subjects with anterior STEMI were analyzed and compared; differences were not significant in terms of age, gender and cardiovascular risk factors. NT-pro-BNP levels were similar (9,887 ± 12,170 vs 8,969 ± 15,053 pg/ml, p = .88), while troponin-I levels were higher in patients with STEMI (4 ± 3.2 vs 13.3 ± 10 ng/dl, p = .03). CgA admission levels were significantly lower in TTS patients (2.2 ± 1.5 vs 7.3 ± 6.2 nMol/l, p = .017), even after multivariable correction for principal bias. CgA levels correlated with NTproBNP levels (p = .02) and were higher in subjects with in-hospital events (3.7 ± 1.1 vs 1.6 ± 1.2 nMol/l, p = .03), even after multivariable forward stepwise analysis (p < .01). CgA levels <3.25 nMol/l (AUC 0.754, 95% C.I. 0.54-0.968) were able to discriminate TTS from anterior STEMI (negative predictive power of 99%).

CONCLUSIONS

Systemic CgA levels in the acute phase of TTS are lower than in anterior STEMI, possibly indicating a greater myocardial catecholamine release rather than adrenal.

Assessment of the German and Italian Stress Cardiomyopathy Score for Risk Stratification for In-hospital Complications in Patients With Takotsubo Syndrome

Importance

Takotsubo syndrome (TTS) is an acute, reversible heart failure syndrome featured by significant rates of in-hospital complications. There is a lack of data for risk stratification during hospitalization.

Objective

To derive a simple clinical score for risk prediction of in-hospital complications among patients with TTS.

Design, Setting, and Participants

In this prognostic study, 1007 consecutive patients were enrolled in the German and Italian Stress Cardiomyopathy (GEIST) registry from July 1, 2007, through December 31, 2017, and identified as the derivation cohort; 946 patients were enrolled in the Spanish Registry for Takotsubo Cardiomyopathy (RETAKO) as the external score validation. An admission risk score was developed using a stepwise multivariable regression analysis from 2 registries. Data analysis was performed from March 1, 2018, through July 31, 2018.

Main Outcomes and Measures

In-hospital complications were defined as death, pulmonary edema, need for invasive ventilation, and cardiogenic shock. Four variables were identified as independent predictors of in-hospital complications and were used for the score: male sex, history of neurologic disorder, right ventricular involvement, and left ventricular ejection fraction (LVEF).

Results

Of the 1007 patients enrolled in the GEIST registry, 107 (10.6%) were male, with mean (SD) age of 69.8 (11.4) years. Overall rate of in-hospital complications was 23.3% (235 of 1007) (death, 4.0%; pulmonary edema, 5.8%; invasive ventilation, 6.4%; and cardiogenic shock, 9.1%). The GEIST prognosis score was derived by providing 20 points each for male sex and history of neurologic disorders and 30 points for right ventricular involvement and then subtracting the value in percent of LVEF (decimal values between 0.15 and 0.70). Score accuracy on area under the receiver operating characteristic curve analysis was 0.71, with a negative predictive power of 87% with scores less than 20. External validation in the RETAKO population (124 [13.1%] male; mean [SD] age, 69.5 [14.9] years) revealed an area under the curve of 0.73 (P = .46 vs GEIST derivation cohort). Stratification into 3 risk groups (<20, 20-40, and >40 points) classified 316 patients (40.9%) as having low risk; 342 (44.3%) as having intermediate risk, and 114 (14.8%) as having high risk of complications. The observed in-hospital complication rates were 12.7% for low-risk patients, 23.4% for intermediate-risk patients, and 58.8% for high-risk patients (P < .001 for trend). After 2.6 years of follow-up, patients with in-hospital complications had significantly higher rates of mortality than those without complications (40% vs 10%, P = .01).

Conclusions and Relevance

The GEIST prognostic score may be useful in early risk stratification for TTS. High-risk patients with TTS may require an intensive care unit stay, and low-risk patients with TTS could be discharged within a few days. In-hospital complications in patients with TTS may be associated with increased risk of long-term mortality.

The Use of Beta Blockers in Takotsubo Syndrome as Compared to Acute Coronary Syndrome

BACKGROUND

Takotsubo syndrome (TTS) and acute coronary syndrome (ACS) patients have a similar mortality rate. In this study, we sought to determine the short- and long-term outcome of TTS patients as compared to ACS patients both treated with beta-blockers.

OBJECTIVES

In the present study we described the data of 5 years of follow up of 103 TTS and 422 ACS patients both treated with beta-blockers.

METHODS

Data from TTS patients were included retrospectively and prospectively, ACS patients were included retrospectively. All retrospectively included patients have been followed up for 5 years. The end point in this study was the occurrence of death.

RESULTS

TTS affected significantly more women (87.4%) than ACS (34.6%) (p < 0.01). TTS patients suffered significantly more often from thromboembolic events (14.6% versus 2.1%; p < 0.01) and cardiogenic shock (11.9% versus 3.6%; p < 0.01) than the ACS group. TTS patients had a significantly higher long-term mortality (within 5 years) as compared to ACS patients (17.5% versus 3.6%) (p < 0.01). Patients of the TTS group compared to the ACS group did not benefit from combination of beta-blockers and ACE-inhibitors in terms of long-term mortality (p < 0.01). As we compare TTS patients who were treated with beta-blockers and ACE-inhibitors versus single use of beta-blockers there was no difference in long-term mortality (p = 0.918).

CONCLUSION

TTS patients had a significantly higher long-term mortality (within 5 years) than patients with an ACS.

Takotsubo syndrome: between evidence, myths, and misunderstandings

Takotsubo syndrome (TS) is an acute cardiac condition characterized by transient wall motion abnormalities mostly of the left ventricle. First described in 1990, TS has gained substantial attention during the past 15 years. However, the disease is still underdiagnosed. Prospective studies on TS are largely lacking, and the condition remains incompletely understood. In addition, significant misconceptions and misunderstandings are evident, contributing to potentially severe underestimation. Here, we review important aspects of TS with a focus on pitfalls, misinterpretations, and knowledge gaps considered important during diagnosis and management of the disease.

Takotsubo syndrome and cardiac implantable electronic device therapy

Recent studies have reported that takotsubo syndrome (TTS) patients are suffering from life-threatening arrhythmias. The aim of our study was to understand the short and long-term usefulness of cardiac implantable electronic devices in TTS patients.We constituted a collective of 142 patients in a bi-centric study diagnosed with TTS between 2003 and 2017. The patient groups, divided according to the treatment with (n = 9, 6.3%) or without cardiac devices (n = 133, 93.7%), were followed-up to determine the importance of devices and its complications. One patient was treated with a permanent pacemaker, five patients with a wearable cardioverter defibrillator, two patients with a subcutaneous defibrillator and one patient with a transvenous defibrillator. Regular device check-up was documented in all patients, presenting an ongoing high-degree AV-block. Neither device complications nor life-threatening tachyarrhythmias were documented after acute TTS event. However, patients comprising the device group suffered significantly more often from a highly reduced EF (30 ± 7.7% versus 39.1 ± 9.7%; p < 0.05), cardiogenic shock with use of inotropic agents (66.6% versus 16.6%; p < 0.05) and cardiopulmonary resuscitation (44.4% versus 5.3%; p < 0.05). Our data confirm the usefulness of pacemaker in TTS patients. However, the cardioverter defibrillator including wearable cardioverter defibrillator may not be recommended.

Studying Brugada Syndrome With an SCN1B Variants in Human-Induced Pluripotent Stem Cell-Derived Cardiomyocytes

Background

Among rare channelopathies BrS patients are at high risk of sudden cardiac death (SCD). SCN5A mutations are found in a quarter of patients. Other rare gene mutations including SCN1B have been implicated to BrS. Studying the human cellular phenotype of BrS associated with rare gene mutation remains lacking.

Objectives

We sought to study the cellular phenotype of BrS with the SCN1B gene variants using human-induced pluripotent stem cell (hiPSCs)–derived cardiomyocytes (hiPSC-CMs).

Methods and Results

A BrS patient suffering from recurrent syncope harboring a two variants (c.629T > C and c.637C > A) in SCN1B, which encodes the function-modifying sodium channel beta1 subunit, and three independent healthy subjects were recruited and their skin biopsies were used to generate hiPSCs, which were differentiated into cardiomyocytes (hiPSC-CMs) for studying the cellular electrophysiology. A significantly reduced peak and late sodium channel current (I_Na) and a shift of activation curve to more positive potential as well as a shift of inactivation curve to more negative potential were detected in hiPSC-CMs of the BrS patient, indicating that the SCN1B variants impact the function of sodium channels in cardiomyocytes. The reduced I_Na led to a reduction of amplitude (APA) and upstroke velocity (V_max) of action potentials. Ajmaline, a sodium channel blocker, showed a stronger effect on APA and Vmax in BrS cells as compared to cells from healthy donors. Furthermore, carbachol was able to increase arrhythmia events and the beating frequency in BrS.

Conclusion

Our hiPSC-CMs from a BrS-patient with two variants in SCN1B recapitulated some key phenotypic features of BrS and can provide a platform for studies on BrS with SCN1B variants.

Drug Testing in Human-Induced Pluripotent Stem Cell-Derived Cardiomyocytes From a Patient With Short QT Syndrome Type 1

Short QT syndrome (SQTS) predisposes afflicted patients to sudden cardiac death. Until now, only one drug-quinidine-has been shown to be effective in patients with SQTS type 1(SQTS1). The objective of this study was to use human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) from a patient with SQTS1 to search for potentially effective drugs for the treatment of SQTS1 patients. Patch clamp and single-cell contraction measurements were employed to assess drug effects. Ivabradine, mexiletine, and ajmaline but not flecainide, ranolazine, or amiodarone prolonged the action potential duration (APD) in hiPSC-CMs from an SQTS1 patient. Ivabradine, ajmaline, and mexiletine inhibited KCNH2 channel currents significantly, which may underlie their APD-prolonging effects. Under proarrhythmic epinephrine stimulation in spontaneously beating SQTS1 hiPSC-CMs, ivabradine, mexiletine, and ajmaline but not flecainide reduced the epinephrine-induced arrhythmic events. The results demonstrate that ivabradine, ajmaline, and mexiletine may be candidate drugs for preventing tachyarrhythmias in SQTS1 patients.

Comparing the variants of takotsubo syndrome: an observational study of the ECG and structural changes from a New Zealand tertiary hospital

OBJECTIVES

In takotsubo syndrome, QTc prolongation is a measure of risk of potentially fatal arrhythmia. It is not known how this risk, or derangement of other markers, differs across the echo variants of takotsubo syndrome. Therefore, we sought to explore whether apical takotsubo syndrome differs from the variants of the syndrome in more ways than just regional wall motion pattern. As the region of affected myocardium is usually larger, we hypothesised that patients with the classic apical ballooning form of takotsubo syndrome would have more severe derangement of their markers.

DESIGN

Observational study of patients gathered from a prospective database (2010-2018) and by retrospective review (2006-2009).

SETTING

The sole tertiary hospital from a New Zealand region in which case clusters of takotsubo syndrome were precipitated by large earthquakes in 2010, 2011 and 2016.

PARTICIPANTS

A total of 222 patients who met a modified version of the Mayo criteria for takotsubo syndrome were included. All patients had digitally archived echocardiograms that were over-read by a second echocardiologist blinded to the clinical report.

PRIMARY OUTCOME MEASURES

Ejection fraction, peak troponin and QTc interval.

RESULTS

Patients with the apical form were older (p=0.011), had a lower initial left ventricular ejection fraction (35% vs 44%, p<0.0001) and a higher peak high-sensitivity troponin I (hsTnI) (p=0.01) than those with variant forms. There was no difference in the electrical abnormalities between the variants (QTc interval, heart rate, PR interval, QRS duration or T-wave axis). There was also no correlation between any of peak hsTnI, peak QTc and ejection fraction. QTc interval increased on day 2 and peaked on day 3 before falling steeply (p<0.0001).

CONCLUSIONS

The variants of takotsubo syndrome differ in more ways than just their echo pattern but do not differ in their electrical abnormalities. There is a dissociation between the structural and electrical abnormalities. QTc peaks on day 3 and then falls steeply.

Short- and Long-Term Incidence of Thromboembolic Events in Takotsubo Syndrome as Compared With Acute Coronary Syndrome

Thromboembolic events are a common complication in Takotsubo syndrome (TTS). However, their long-term incidence compared with acute coronary syndrome (ACS) is lacking. In-hospital and long-term incidence of thromboembolic events of 138 consecutive patients with TTS were compared with 138 sex- and age-matched patients with ACS. Predictors of events were analyzed. The incidence of thromboembolic events in TTS was 2-fold higher than ACS (21% vs 9%; P < .01) over a mean follow-up of 5 years. Although the left ventricular ejection fraction (LVEF) at event was significantly lower in TTS compared with ACS (38% [9%] vs 54% [11%]; P < .01), the follow-up LVEF was comparable. Patients with TTS suffering from thromboembolic events were more often treated with anticoagulation compared with ACS (44.8% vs 8.3%, P = .03). However, more patients presenting with ACS (100% vs 48.3%; P < .01) were discharged on aspirin. Only elevated C-reactive protein was a predictor of thromboembolic events using multivariate analysis (hazard ratio 1.1, 95% confidence interval, 1.0-1.2; P < .01). In conclusion, the risk of thromboembolic events in TTS was significantly higher than the risk of thromboembolic events in ACS over a mean follow-up of 5 years.

Plasma Epinephrine Level and its Causal Link to Takotsubo Syndrome Revisited: Critical Review with a Diverse Conclusion

Takotsubo syndrome (TS) is a recognized acute cardiac syndrome with a clinical presentation resembling that of an acute coronary syndrome (ACS). The defining feature of TS is the reversible left ventricular wall motion abnormality (LVWMA), which has a unique circumferential pattern resulting in a conspicuous ballooning of the left ventricle during systole, and extending beyond the coronary artery supply territory. The pathogenesis of TS is still elusive and several pathophysiological mechanisms have been proposed. A common portrayal of the syndrome in the literature is that the disease is characterized by massive surge of plasma catecholamines including epinephrine. Based on the assumption of massive plasma epinephrine elevation, some investigators hypothesized that the circulatory plasma epinephrine plays a pivotal role in the pathogenesis of TS. One typical such hypothesis is epinephrine induced switch in signal trafficking causing apical or mid-apical ballooning in TS. In-depth analysis of the literature reveals that no study with certainty has shown "massive" plasma epinephrine elevations in TS. Furthermore, the literature evidences challenging the epinephrine-induced switch in signal trafficking are substantial. In this review, sufficient data, indicating that the plasma epinephrine in TS is either normal or moderately elevated in all studies, are provided. Noteworthy, epinephrine may act as a trigger factor for TS-induction but there is no evidence for a direct causal link between epinephrine and TS.