Stress cardiomyopathy

Upregulation of neuropeptide Y in cardiac sympathetic nerves induces stress (Takotsubo) cardiomyopathy

Substantial emotional or physical stress may lead to an imbalance in the brain, resulting in stress cardiomyopathy (SC) and transient left ventricular (LV) apical ballooning. Even though these conditions are severe, their precise underlying mechanisms remain unclear. Appropriate animal models are needed to elucidate the precise mechanisms. In this study, we established a new animal model of epilepsy-induced SC. The SC model showed an increased expression of the acute phase reaction protein, c-Fos, in the paraventricular hypothalamic nucleus (PVN), which is the sympathetic nerve center of the brain. Furthermore, we observed a significant upregulation of neuropeptide Y (NPY) expression in the left stellate ganglion (SG) and cardiac sympathetic nerves. NPY showed neither positive nor negative inotropic and chronotropic effects. On the contrary, NPY could interrupt β-adrenergic signaling in cardiomyocytes when exposure to NPY precedes exposure to noradrenaline. Moreover, its elimination in the left SG via siRNA treatment tended to reduce the incidence of SC. Thus, our results indicated that upstream sympathetic activation induced significant upregulation of NPY in the left SG and cardiac sympathetic nerves, resulting in cardiac dysfunctions like SC.

Takotsubo Syndrome in New Zealand: Current Knowledge and Future Challenges

Takotsubo syndrome (TS), also known as apical ballooning syndrome is a transient stress-related cardiomyopathy characterised by acute but reversible left ventricular dysfunction. The condition tends to occur in postmenopausal women after a stressful event. At presentation TS typically mimics acute myocardial infarction (MI) and the incidence of TS has been increasing worldwide. This is likely a consequence of an improved awareness of the existence of this syndrome and easier access to early echocardiography and coronary angiography. However, its aetiology remains poorly understood and it is probably still underdiagnosed. Similar to other countries. TS is being increasingly recognised in New Zealand. In this review, we discuss the demographics, clinical features and outcomes of patients with TS in New Zealand. Doing so informs us not only of the pattern of disease in New Zealand but it also provides insights into the condition itself. This article is protected by copyright. All rights reserved.

Autopsy Histopathologic Cardiac Findings in Two Adolescents Following the Second COVID-19 Vaccine Dose

CONTEXT

- Myocarditis in adolescents has been diagnosed clinically following the administration of the second dose of an mRNA vaccine for coronavirus disease 2019 (COVID-19).

OBJECTIVE

- To examine the autopsy microscopic cardiac findings in adolescent deaths that occurred shortly following administration of the second Pfizer-BioNTech COVID-19 dose to determine if the "myocarditis" described in these instances has the typical histopathology of myocarditis.

DESIGN

- Clinical and autopsy investigation of two teenage boys who died shortly following administration of the second Pfizer-BioNTech COVID-19 dose.

RESULTS

- The microscopic examination revealed features resembling a catecholamine-induced injury, not typical myocarditis pathology.

CONCLUSIONS

- The myocardial injury seen in these post-vaccine hearts is different from typical myocarditis and has an appearance most closely resembling a catecholamine-mediated stress (toxic) cardiomyopathy. Understanding that these instances are different from typical myocarditis and that cytokine storm has a known feedback loop with catecholamines may help guide screening and therapy.

Case Report: Abnormal ECG in a Patient With Acute Pancreatitis

Background: Both acute pancreatitis and acute myocardial infarction (AMI) are rapidly progressive and frequently fatal diseases that can be interrelated and lead to a vicious cycle for further problems. The concomitant occurrence of AMI and acute pancreatitis is rare but critical, and efficient diagnosis and treatment of such patients are challenging.

Case Summary: We reported an uncommon case of abnormal ECG findings in a 63-year-old woman with acute pancreatitis. The patient exhibited increased biomarkers of myocardial injury, such as creatine kinase-MB (CK-MB) and troponin T, as well as ST segment elevation in inferior leads II, III, and aVF. Both of these have been previously observed in patients with acute abdomen in the absence of ST-segment elevation myocardial infarction (STEMI), including pancreatitis. In addition, lacking complaints of chest pain or tightness was also supportive of this idea. Echocardiography indicated abnormalities in the functioning of the left inferior posterior wall segments and decreased overall systolic function of the left ventricle with a 51% ejection fraction. Eventually, AMI was diagnosed after coronary computed tomography angiography (CCTA) showing critical stenosis of the right coronary artery and left anterior descending artery segments. The patient was urgently transferred to intensive care unit and was treated with anticoagulation, antiplatelet aggregation, lipid-lowering and other palliative drugs.

Conclusion: Concomitant acute pancreatitis and AMI are often considered to be critical conditions with a poor prognosis. Therefore, it is important to rapidly identify this condition and consider transferring patients for multidisciplinary supportive care.

Impact of malnutrition on in-hospital outcomes in takotsubo cardiomyopathy

OBJECTIVE

This study assesses the effect of malnutrition on the in-hospital outcomes of patients with takotsubo cardiomyopathy (TCM).

METHODS

We performed a retrospective cohort analysis using the International Classification of Diseases, Tenth Revision, Clinical Modification (ICD-10-CM) codes for a primary diagnosis of TCM from the National Inpatient Sample database (2016-2018). A concurrent diagnosis of malnutrition was then identified, and these patients were divided into the malnutrition group and non-malnutrition group. To adjust for underlying risk factors, a multivariable logistic regression model was employed followed by a propensity score matching analysis for the malnutrition and the non-malnutrition group. We then compared the in-hospital outcomes between these two groups.

RESULTS

Among 4733 patients with a primary diagnosis of TCM, 221 (4.7%) patients with TCM were found to be malnourished. After propensity score matching, patients with TCM with malnutrition were found to have a higher mortality rate (8.3% versus 2.0%, P < 0.001), a higher rate of complications including cardiogenic shock (16.1% versus 7.0%, P < 0.001), ventricular arrhythmia (8.8% versus 3.9%, P = 0.01), acute kidney injury (24.9% versus 10.6%, P < 0.001), and acute respiratory failure (32.7% versus 17.8%, P < 0.001). There was no statistically significant difference in the incidence of cardiac arrest between the two groups. Malnutrition of severe degree was associated with a sevenfold (odds ratio 6.8, 95% confidence interval, 3.2-13.4) increased risk of in-hospital mortality compared with those without malnutrition.

CONCLUSION

Patients with malnutrition who were admitted with TCM were associated with higher rates of in-hospital mortality and complications compared with those without malnutrition.

A Rare Case of Takotsubo Cardiomyopathy in a Patient With No Identifiable Emotional or Physical Stressors

Takotsubo cardiomyopathy (TCM) is a cardiac condition that presents with features of acute myocardial infarction and transient systolic dysfunction without angiographic findings of obstructive coronary heart disease. Common presenting symptoms include acute substernal chest pain, dyspnea and syncope. It is usually triggered by recent emotional or physical stress such as head trauma, stroke, sepsis, overproduction of catecholamines such as pheochromocytoma or following Myasthenia crisis. We are here to report a case of TCM who does not have any identifiable emotional or physical stress prior to the event. The patient was a 76-year-old Caucasian female with a past medical history of hypertension who presented to the hospital with chest pain which initially was treated as non-ST elevation myocardial infarction (NSTEMI) with aspirin, ticagrelor and heparin infusion. Cardiac catheterization later revealed non-obstructive coronary artery disease but showed akinesis of inferior, apical and anterior walls with hyperdynamic basal segments indicating TCM.

Africanized Honey Bee Sting-Induced Stress-Related Cardiomyopathy: A Bee or Octopus Trap

The Africanized honey bee commonly referred to as the "killer bee," is a hybrid of the East African lowland honey bee with various European honey bees. These bees tend to be more hostile as compared to other bee species. Their stings may have devastating clinical sequelae, including cardiovascular, cerebrovascular events, and fatalities. We report the first-in-Caribbean case of a middle-aged woman who experienced stress-related, Takotsubo cardiomyopathy (also known as stress-related cardiomyopathy [SRC]) after being afflicted with innumerable Africanized honey bee stings.

Key clinical message: The clinician should be cognizant of Takotsubo's cardiomyopathy as a potential sequela of Hymenoptera envenomation and anaphylaxis.

Takotsubo Cardiomyopathy: Current Treatment

Management of takotsubo syndrome (TTS) is currently empirical and supportive, via extrapolation of therapeutic principles worked out for other cardiovascular pathologies. Although it has been emphasized that such non-specific therapies for TTS are consequent to its still elusive pathophysiology, one wonders whether it does not necessarily follow that the absence of knowledge of TTS' pathophysiological underpinnings should prevent us for searching, designing, or even finding, therapies efficacious for its management. Additionally, it is conceivable that therapy for TTS may be in response to pathophysiological/pathoanatomic/pathohistological consequences (e.g., "myocardial stunning/reperfusion injury"), common to both TTS and coronary artery disease, or other cardiovascular disorders). The present review outlines the whole range of management principles of TTS during its acute phase and at follow-up, including considerations pertaining to the recurrence of TTS, and commences with the idea that occasionally management of TTS should consist of mere observation along the "first do no harm" principle, while self-healing is under way. Finally, some new therapeutic hypotheses (i.e., large doses of insulin infusions in association with the employment of intravenous short- and ultrashort-acting β-blockers) are being entertained, based on previous extensive animal work and limited application in patients with neurogenic cardiomyopathy and TTS.

The role of adrenergic and muscarinic receptors in stress-induced cardiac injury

Takotsubo syndrome (TS) is a rare but dangerous disease that can be fatal. The pathogenesis of TS is not well understood because there is no animal model of TS that fully mimics TS. It has now been documented that stress exposure (24 h) of rats induced the state which is similar TS in human: contracture damage of myofibrils, elevation of the serum creatine kinase MB level, increased ^99mTc-pyrophosphate (^99mTc-PYP) accumulation in the heart, QTc interval prolongation, and contractility dysfunction of the heart. Immobilization stress resulted in an increase in coronary blood flow. Emotional stress increased the serum catecholamine level. Blockade of β₁-adrenergic receptor (AR) prevented stress-induced cardiac injury (SICI). Blockade of β₂-AR aggravated stress-induced cardiac injury. Stimulation of β₂-AR increased cardiac tolerance to stress. Inhibition of β₃-AR, α₁-AR had no effect on SICI. Blockade of peripheral muscarinic receptors or α₂-AR aggravated SICI. Pretreatment with the selective β₁-AR antagonist atenolol attenuates stress-induced cardiac contractility dysfunction, but recovery of cardiac contractility is not complete. There is indirect evidence that circulating catecholamines play an important role in SICI. Consequently, the activation of β₁-AR plays a significant role in SICI. However, there are other receptors which are also involved in SICI and require further investigation.

Current strategies with sensing technologies to eliminate stress cardiomyopathy

Stress cardiomyopathy refers weakening of heart muscle due to the continuous stress. Generally, the severe status of stress cardiomyopathy has been revealed after damaging the muscles and measured by the physical changes in the heart system. To overcome this issue, biosensor can be used, which could eliminate the late identification stress cardiomyopathy. With biosensors, different stress markers such as epinephrine, dopamine, catecholamine, α-amylase, norepinephrine, serotonin and cortisol have been identified by a wide range of developments. These biosensors are available from laboratory to industry at the ranges of nano to macrodevices. To merge with the identification of stress cardiomyopathy, the above strategies might be utilized properly and can aid to reduce the stress-related problems. This overview gleaned the currently available biosensing methods and the associated biomarkers at various stages of the developments and implementations of stress cardiomyopathy.

Advantage and use of S-patch cardio solution in competitive motor sports

BACKGROUND

Motorsport karting has developed into a professional international competition. Kart racing poses a unique set of physiologic challenges for athletes who compete in this sport. Until today no major study has evaluated the physical and cardiac challenge in professional kart racing.

OBJECTIVE

The aim for this study was to measure and analyze heart rate and cardiac rhythm by a mobile, smartphone based ECG (s-patch) on professional kart-race-drivers during actual karting races through annual seasons to test the hypotheses that high g-force and stress could trigger cardiac arrhythmia.

MATERIAL AND METHODS

ECG-data from kart-drivers were acquired during local races, the ADAC Kart-Masters (KZ2), the German Kart Championship (DSKC) and the European Championship Senior CIK-FIA-Serie and analyzed in this observational study. In total, free practice, qualifying practice and 32 races were assessed during the kart season 2019. Data were interpreted by two independent experienced physicians.

RESULTS

The average heart rate (HR) during a selected German Kart Championship (DSKC) race in Genk (Belgium) was 169 beats min-1. The longest R-R interval was 0.72 sec. The average HR during a selected European Championship CIK-FIA-race in Lonato (Italy) was 160 beats min-1. The longest R-R interval was 0.74 sec. The average HR during a selected ADAC Kart-Masters (KZ2) races in Wackersdorf (Germany) was 147 beats min-1. The longest R-R interval was 0.86 sec. In total 32 races could be recorded successful. No couplets or bigeminy cycles were detected. In one other kart racer a supraventricular extrasystole and a ventricular extrasystole was detected. Interestingly, kart-drivers were found to have sinustachycardia throughout the races most likely triggered by emotional and physiological stress during speeding.

CONCLUSION

Professional kart racing drivers had sinustachycardia with heart rates up to 193 beats min-1 during races. This is most likely attributed to a considerably high emotional and physiological stress affecting the cardiovascular system. Episodes of tachycardia positively correlated with mean speed. In the warm-up lap the heart rate was significantly lower in comparison to the race, suggesting that faster driving speed would induce greater cardiovascular stress to professional drivers during actual races. The experimental results showed that the proposed S-patch system provided a good ECG signal quality with accurate measurements even during the kart race and could detect the ECG features of the race in real time. The cardiac interpretation software performs well and is a useful tool to assist clinicians.

Combining tissue engineering and optical imaging approaches to explore interactions along the neuro-cardiac axis

Interactions along the neuro-cardiac axis are being explored with regard to their involvement in cardiac diseases, including catecholaminergic polymorphic ventricular tachycardia, hypertension, atrial fibrillation, long QT syndrome and sudden death in epilepsy. Interrogation of the pathophysiology and pathogenesis of neuro-cardiac diseases in animal models present challenges resulting from species differences, phenotypic variation, developmental effects and limited availability of data relevant at both the tissue and cellular level. By contrast, tissue-engineered models containing cardiomyocytes and peripheral sympathetic and parasympathetic neurons afford characterization of cellular- and tissue-level behaviours while maintaining precise control over developmental conditions, cellular genotype and phenotype. Such approaches are uniquely suited to long-term, high-throughput characterization using optical recording techniques with the potential for increased translational benefit compared to more established techniques. Furthermore, tissue-engineered constructs provide an intermediary between whole animal/tissue experiments and in silico models. This paper reviews the advantages of tissue engineering methods of multiple cell types and optical imaging techniques for the characterization of neuro-cardiac diseases.

Increased Plasma Cardiac Troponin I in Live-Stranded Cetaceans: Correlation with Pathological Findings of Acute Cardiac Injury

Capture myopathy (CM), is a syndrome that occurs as the result of the stress during and after capture, handling, restraint, and transport of wild animals. Although CM has been described for many species of cetaceans, characterization of the acute cardiac injury - an important component of this syndrome - are still scarce. In this study, we firstly estimated a normal range for cardiac troponin I (cTnI) on cetaceans. Here, through biochemical analysis (especially of cTnI) and histopathological, histochemical, and immunohistochemical correlations with decreased troponin immunolabelling, we studied the cardiac injury in live-stranded cetaceans. Nine cetaceans which stranded alive on the Canary Islands (January 2016 - June 2019) were included in this study. Sampled individuals presented elevated values of plasma cTnI, which were correlated to histopathological lesions comprised of vascular changes and acute degenerative lesions. Immunohistochemically, injured cardiomyocytes showed a decreased intrafibrillar troponin immunoreaction. This is the first attempt to establish a normal baseline range for cTnI in cetaceans, and the first study comparing plasma biomarkers values with histopathological and immunohistochemical findings. This approach allowed us to demonstrate the degree of cardiac damage as a result of injury, consistent with ischemia-reperfusion lesions. The knowledge gained here could improve decision-making procedures during stressful situations, mainly in live-strandings, handling, and rehabilitation, thereby reducing the mortality of cetaceans.

Skeletal and Cardiac Rhabdomyolysis in a Live-Stranded Neonatal Bryde's Whale With Fetal Distress

The main objective of wildlife forensic investigation is to recognize pathologic changes and cause of death. Even though it may not always be possible to determine the specific illness and/or etiology, the description and subsequent interpretation of the injuries provide an invaluable understanding of pathology in cetacean post-mortem investigations. Although pathological studies have been previously reported in various cetacean species, such descriptions of the infraorder Mysticeti remain rare. A live-stranded neonatal Bryde's whale (Balaenoptera edeni) which subsequently died soon after the stranding, was assessed by physical exam, blood examination, gross necropsy evaluation, histopathology, and immunohistochemistry. It presented with elevated serum levels of creatine kinase, cardiac troponin I, urea, and creatinine. Microscopically, we observed keratin spicules (squamous epithelial cells) and areas of atelectasis in the lungs. Acute degeneration in the myocytes and cardiomyocytes were comparable to the findings previously described in cases of capture myopathy in live-stranded cetaceans. Immunohistochemistry biomarkers such as myoglobin, fibrinogen, and troponin were analyzed. Skeletal and myocardial damage has been documented in several cetacean species. However, this is the first reported case of skeletal and cardiac rhabdomyolysis associated with live-stranding in a newborn Bryde's whale that suffered from fetal distress.

Stress cardiomyopathy in stranded cetaceans: a histological, histochemical and immunohistochemical study

BACKGROUND

Free-living cetaceans are exposed to a wide variety of stressful situations, including live stranding and interaction with human beings (capture myopathy), vessel strikes, and fishing activities (bycatch), which affect their wellbeing and potentially lead to stress cardiomyopathy (SCMP).

METHODS

Here, the authors aimed to characterise SCMP of stranded cetaceans as an injury resulting from extreme stress responses, based on pathological analyses (histological, histochemical and immunohistochemical). Specifically, the authors examined heart samples from 67 cetaceans found ashore (48 live strandings, seven dead from ship collision and 12 dead from bycatch) on the coast of Spain, more specifically in the Canary Islands from 2000 to 2016 and Andalusia from 2011 to 2014.

RESULTS

The microscopic findings were characterised by vascular changes, acute or subacute cardiac degenerative necrotic lesions, interstitial myoglobin globules, and infiltration of inflammatory cells. Immunohistochemically, cardiac troponin I, cardiac troponin C and myoglobin were depleted, along with fibrinogen being expressed in the degenerated/necrotic cardiomyocytes. A perivascular pattern was also identified and described in the damaged cardiomyocytes.

CONCLUSIONS

This study advances current knowledge about the pathologies of cetaceans and their implications on conserving this group of animals by reducing mortality and enhancing their treatment and subsequent rehabilitation to the marine environment.

Takotsubo cardiomyopathy and giant r wave syndrome mimicking acute myocardial infarction: A case report

RATIONALE

The clinical features of Takotsubo cardiomyopathy largely overlap with those of acute myocardial infarction, especially in the presence of ST-segment elevation on the initial electrocardiogram. Giant R wave syndrome has mainly been observed in the hyperacute phase of acute myocardial infarction.

PATIENT CONCERNS

In this study, we report a unique case of Takotsubo cardiomyopathy that caused giant R wave syndrome.

DIAGNOSIS

A 71-year-old woman was transferred to hospital with new onset chest pain. An initial electrocardiogram showed ST-segment elevation in the inferior wall and anterior wall leads. Her initial cardiac troponin I levels were elevated. Acute myocardial infarction was suspected and the patient underwent emergent cardiac catheterization. A coronary angiography showed no overt stenosis in the coronary artery. After 2 hours, her chest pain disappeared and an electrocardiogram revealed that the ST segment had decreased markedly. However, on day 3, an electrocardiogram of the V1-V6 leads revealed the formation of giant R wave syndrome: giant R waves merging with the markedly elevated ST segments and the obliteration of S waves. Cardiac echocardiography showed hypokinetic apical mid-segments and hyperkinetic basal segments of the left ventricle, low left ventricular ejection (42%), and enlargement of the left ventricle. On the basis of these findings, the patient was diagnosed with early recurrent Takotsubo cardiomyopathy.

INTERVENTIONS

The patient has been treated by levosimendan and furosemide to improve cardiac function before leaving the hospital. After discharge, she was treated with a beta blocker.

OUTCOMES

The patient was discharged 2 weeks later in stable condition without chest pain. One year later, during her follow-up, a repeat echocardiogram and ECG showed normal findings.

LESSONS

To the best of our knowledge, this is the first report of giant R wave syndrome on electrocardiogram following Takotsubo cardiomyopathy. Takotsubo cardiomyopathy, especially presenting with giant R wave syndrome on electrocardiogram, remains a challenging condition given its similarity to acute myocardial infarction in its early phase.

Stress induced cardiomyopathy due to a Mexican earthquake

Takotsubo Cardiomyopathy mainly occurs in postmenopausal women, with or without cardiovascular disease, and is commonly associated with emotional or physical stress. After nearly 27 years of extensive efforts towards a better understanding of this disorder, current knowledge remains limited. Many people suffer post-traumatic stress, and this situation can be associated to stress cardiomyopathy. The case is presented of a female who suffers stress associated with the earthquake of 19 September 2017 in Mexico City, and arrived in the Emergency Department in cardiogenic shock.

Takotsubo syndrome-associated ventricular standstill in a peripartum patient: case report and review of the literature

Takotsubo syndrome is classically characterized by apical ballooning and left ventricle akinesis associated with an underlying catecholamine surge. In patients with suspected Takotsubo syndrome, clinicians should be vigilant for acute coronary syndrome and arrhythmias. Ventricular standstill with underlying Takotsubo syndrome should be managed with a dual‐chambered pacemaker to improve patient outcome.

Estrogen deficiency compromised the β2AR-Gs/Gi coupling: implications for arrhythmia and cardiac injury

Estrogen and β₂-adrenergic receptors (β₂AR) play important roles in the processes that protect the heart. Here, we investigated how ovariectomy influenced the β₂AR downstream pathways in the context of catecholaminergic stress. In vivo and in vitro stress models were developed in female Sprague-Dawley (SD) rats by epinephrine (Epi) treatments. The cardiac function was evaluated at in vivo and in vitro levels in terms of contraction, rhythm, and injury. We found that myocardial contractility was not significantly different between Sham and ovariectomized (OVX) group rats in the normal state. However, Epi pretreatment decreased the contractility and increased abnormal rhythms especially in OVX group, which were attributed to lack of estrogen. Inhibition of the β₂AR-Gi-PI3K/p38MAPK pathway with ICI118,551, PTX or LY294002 increased contractility and aggravated Epi-induced injury on cardiomyocytes, decreased p38MAPK phosphorylation, and only increased arrhythmia in Sham group. These results indicated that OVX exacerbated cardiac injury and abnormal rhythms through β₂AR-Gi-PI3K and β₂AR-Gi-p38MAPK pathways, respectively. In normal state, the levels of activated Gi were similar in both groups, but those of cAMP and activated Gs were higher in OVX group. Epi treatment increased activated Gi (especially in Sham group) and activated Gs and cAMP in Sham group but decreased it in OVX group. These results suggested that estrogen increased the Gi activity in normal and stress states and Gs activity in stress state. These results indicated that lack of estrogen impaired the β₂AR-Gs/Gi coupling during stress which compromised cardiac contractility and increased abnormal rhythms.

Different roles of β-arrestin and the PKA pathway in mitochondrial ROS production induced by acute β-adrenergic receptor stimulation in neonatal mouse cardiomyocytes

Reactive oxygen species (ROS) play a crucial role in various physiological and pathological processes mediated by β-adrenergic receptors (β-ARs) in cardiomyocytes. However, the sources and signaling pathways involved in ROS production induced by acute β-AR activation have not yet been fully defined. In primary neonatal mouse cardiomyocytes (NMCMs), the β-AR agonist isoproterenol (ISO) induced a rapid increase in mitochondrial ROS and total ROS production. Both the expression and activity of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase 2/4 (NOX 2/4) remained unchanged after 2 h of ISO treatment, suggesting that acute ISO stimulation mainly induces mitochondrial ROS production in NMCMs. Knockdown of β-arrestin1, but not β-arrestin2, inhibited ISO-induced mitochondrial ROS production within 1-2 h after ISO treatment. Moreover, forskolin, an adenylyl cyclase (AC) activator, rapidly increased mitochondrial ROS as early as 15 min after ISO treatment. Inhibition of the cyclic adenosine monophosphate (cAMP)/protein kinase A (PKA) pathway abolished the mitochondrial ROS production within 15-60 min after ISO treatment. In conclusion, mitochondria are the major source of ROS production upon acute ISO stimulation. β-arrestin1, but not β-arrestin2, is involved in ISO-induced mitochondrial ROS production. Upon acute β-AR stimulation in NMCMs, the classical cAMP/PKA pathway is responsible for faster mitochondrial ROS production, whereas β-arrestin1 signaling is responsible for slower mitochondrial ROS production.

Takotsubo Cardiomyopathy Associated with Levothyroxine Over-replacement

Takotsubo cardiomyopathy (TC) is characterised by acute, transient left ventricular apical ballooning precipitated by emotional or physiologically stressful stimuli and has been previously associated with Grave’s disease based on a few clinical reports. More recently, the association with exogenous thyrotoxicosis and radioiodine-induced thyroiditis has also been described. Iatrogenic hyperthyroidism on patients on levothyroxine replacement therapy for hypothyroidism has not been reported as a cause of TC. The authors describe two female patients with TC associated with levothyroxine over-replacement. A 74-year-old and a 48-year-old female patient, medicated with levothyroxine (respectively, 2.27 μg/kg and 1.85 μg/kg) for autoimmune thyroiditis were admitted to our emergency room with precordial pain. The first had an electrocardiogram with ST-segment elevation in the anterior precordial leads, and the latter had sinus tachycardia with deep T-wave inversion and QT interval prolongation. Further investigation revealed a mild elevation of cardiac biomarker levels and severe apical hypokinesis, but no significant coronary lesions on catheterisation. The suppressed thyroid stimulating hormone (TSH) levels were verified in the cardiac intensive care unit: 0.21 and 0.07 mIU/l (0.35–5.50) respectively. Both patients showed improvement of the apical hypokinesis on the discharge echocardiogram and normalisation of cardiac biomarker levels. Levothyroxine dose was reduced. This case report focuses on the cardiovascular risks of thyrotoxicosis, emphasises the importance of correct dose adjustment on patients under levothyroxine replacement therapy and stresses that TSH should be determined in patients presenting with acute coronary syndrome and typical findings of TC.

Conventional Coronary Angiography Induced Takotsubo Cardiomyopathy Complicated with Cardiac Tamponade

Takotsubo cardiomyopathy (TCM) is a transient left ventricular dysfunction that typically occurs after emotional or physical stress. TCM has a benign prognosis and serious complications are uncommon. However, though very rarely reported, cardiac tamponade has occurred on some occasions. We hereby report the case of a 70-year-old woman who underwent coronary angiography with an ergonovine provocation test to evaluate recurrent chest pain and was readmitted 7 days later presenting with TCM, followed by left ventricular outflow tract obstruction and cardiac tamponade.

Takotsubo Syndrome-Scientific Basis for Current Treatment Strategies

Takotsubo syndrome (TS) is characterized by severe reversible left ventricular (LV) wall motion abnormality in the absence of explanatory coronary lesion. Despite an increasing number of patients diagnosed with TS worldwide, there are no randomized clinical trials. In mild cases, no treatment or a short course of limited anticoagulation therapy may be sufficient. Positive inotropic and vasodilating agents should be avoided. In severe cases with refractory cardiogenic shock, early treatment with mechanical support using venoarterial extracorporeal membrane oxygenation or a LV assist device should be considered.

Takotsubo Syndrome: Insights from Japan

We report the history and new insights of takotsubo syndrome based on the achievements that Japanese researchers have contributed and summarize the evidence originally presented from Japan. Takotsubo syndrome is a newly described heart failure characterized by transient left ventricular dysfunction. We should be aware of this entity as a syndrome, not actual cardiomyopathy. Japanese researchers focus on the experimental approaches for clinical diagnosis and treatment of takotsubo syndrome. As representatives from a country originally naming this syndrome takotsubo, a global registry for takotsubo syndrome including Japan should be established.

Stress cardiomyopathy: Is it limited to Takotsubo syndrome? Problems of definition

In 2006, Takotsubo syndrome (TTC) was described as a distinct type of stress-induced cardiomyopathy (stress cardiomyopathy). However, when thinking about Takotsubo cardiomyopathy from the viewpoints of the AHA and ESC classifications, 2 possible problems may arise. The first potential problem is that a forecast of disease outcome is lacking in the ESC classification, whereas the AHA only states that 'outcome is favorable with appropriate medical therapy'. However, based on the literature data, one can make a general conclusion that occurrence of myocardial lesions in TTC (i.e., myocardial fibrosis and contraction-band necrosis) causes the same effects as in other diseases with similar levels of myocardial damage and should not be considered to have a lesser impact on mortality. To summarise, TTC can cause not only severe complications such as pulmonary oedema, cardiogenic shock, and dangerous ventricular arrhythmias, but also damage to the myocardium, which can result in the development of potentially fatal conditions even after the disappearance of LV apical ballooning. The second potential problem arises from the definition of TTC as a stress cardiomyopathy in the AHA classification. In fact, the main factors leading to TTC are stress and microvascular anginas, since, as has been already discussed, coronary spasm can cause myocardium stunning, resulting in persistent apical ballooning. Thus, based on this review, 3 distinct types of stress cardiomyopathies exist (variant angina, microvascular angina, and TTC), with poor prognosis. Adding these diseases to the classification of cardiomyopathies will facilitate diagnosis and preventive prolonged treatment, which should include intensive anti-stress therapy.

Takotsubo cardiomyopathy precipitated by negative pressure pulmonary oedema following total thyroidectomy

'Takotsubo cardiomyopathy (TCM)' or 'stress cardiomyopathy' is a reversible cardiomyopathy that is precipitated by intense emotional or physical stress. This syndrome is characterised by symptoms mimicking acute coronary syndrome with transient systolic dysfunction associated with regional wall motion abnormalities, which extend beyond a single coronary vascular bed in the absence of obstructive coronary vascular disease. The presentation of TCM and myocardial infarction is similar with sudden onset of chest pain, breathlessness as well as abnormalities in both the electrocardiogram and cardiac enzymes. It is difficult to differentiate between the two until cardiac catheterisation establishes the diagnosis. We report a case of TCM in a post-menopausal female, precipitated by negative pressure pulmonary oedema following total thyroidectomy in whom timely cardiac catheterisation established the diagnosis and influenced the management. Heightened awareness of this unique cardiomyopathy is essential to have a high index of suspicion in at-risk population for the prompt diagnosis of stress-related cardiomyopathy syndromes occurring in the perioperative period.

Acute Stress Decreases but Chronic Stress Increases Myocardial Sensitivity to Ischemic Injury in Rodents

Cardiovascular disease (CVD) is the largest cause of mortality worldwide, and stress is a significant contributor to the development of CVD. The relationship between acute and chronic stress and CVD is well evidenced. Acute stress can lead to arrhythmias and ischemic injury. However, recent evidence in rodent models suggests that acute stress can decrease sensitivity to myocardial ischemia-reperfusion injury (IRI). Conversely, chronic stress is arrhythmogenic and increases sensitivity to myocardial IRI. Few studies have examined the impact of validated animal models of stress-related psychological disorders on the ischemic heart. This review examines the work that has been completed using rat models to study the effects of stress on myocardial sensitivity to ischemic injury. Utilization of animal models of stress-related psychological disorders is critical in the prevention and treatment of cardiovascular disorders in patients experiencing stress-related psychiatric conditions.

Takotsubo cardiomyopathy: A potentially serious trap (Data from the International Takotsubo Cardiomyopathy Registry)

Takotsubo cardiomyopathy (TTC) is an acute cardiac condition characterized by transient left ventricular dysfunction with wall motion abnormalities, most commonly in the form of apical ballooning. Despite being considered as a generally benign condition, many studies have emphasized potentially sinister outcomes associated with TTC. In this article, we review the most recent results of the International Takotsubo Registry, which investigated the clinical features, prognostic predictors, and outcomes of 1750 patients.

Predictors of short- and long-term outcomes of Takotsubo cardiomyopathy

Takotsubo cardiomyopathy (TC) is a reversible cardiomyopathy with a benign short-term prognosis but is associated with recurrence rate of 10%. Clinical variables that predict long-term mortality and recurrence are unknown; 56 consecutive patients presenting to a single urban medical center who fulfilled the Mayo Clinic criteria for the diagnosis of TC were included. Patients were followed with 100% completeness; >60 clinical factors were analyzed, including presentation, treatment, electrocardiogram, and echocardiographic, angiographic, and demographic variables. Survival analysis was performed using the Kaplan-Meier function and Cox proportional hazards regression models. There were 15 deaths during follow-up: 5 in-hospital, 4 before 90 days, and 6 after 90 days. Mean survival was 4.47 years (95% confidence interval 3.81 to 5.13). All short-term survivors had repeat ejection fraction evaluation demonstrating improvement; 45 of 56 patients were women and 96% were postmenopausal. The nonfatal recurrence rate was 1.8%. QTc interval at presentation was the factor most strongly predictive of overall outcome, after intubation. All patients with mortality had QTc intervals between 400 and 550 ms. In conclusion, this study demonstrates the prognostic significance of QTc prolongation at presentation in TC. Because the cause of TC involves intense catecholamine release and hyperadrenergic tone, the QTc may reflect the individual impact on myocardial repolarization and the balance between sympathetic innervation and parasympathetic compensation. In conclusion, in this series, TC was associated with an 8.9% in-hospital mortality, an additional 17.9% mortality after discharge, and a nonfatal recurrence rate of 1.8%. Moreover, the QTc on presentation with TC was predictive of outcome.

Impact of Brain Natriuretic Peptide, Calcium Channel Blockers, and Body Mass Index on Recovery Time from Left Ventricular Systolic Dysfunction in Patients With Takotsubo Cardiomyopathy

Takotsubo cardiomyopathy (TC) is generally recognized to have a good prognosis, but it can be rarely aggravated. We sought to investigate the clinical characteristics of TC and to evaluate the effects of clinical parameters on predicting delayed recovery. We enrolled consecutive patients with TC admitted to our hospital from January 1991 to January 2014. We defined delayed recovery as sustained left ventricular (LV) systolic dysfunction requiring ≥10 days for LV contraction to normalize. We screened 9,630 patients suspected of having acute coronary syndrome, and 60 patients (0.6%; men/women: 20/38; mean age: 69.7 ± 11.9 years) were diagnosed as having TC. With the exception of 2 patients who died before LV systolic function improved, all patients recovered from LV systolic dysfunction within 6 months; the mean recovery period was 9.1 ± 11.5 days. Twenty-eight patients met the criteria for delayed recovery. Univariate logistic regression analyses showed that male gender, LV end-diastolic diameter, brain natriuretic peptide (BNP) level, body mass index (BMI), and nonuse of calcium channel blockers (CCBs) at baseline were associated with delayed recovery. Among these factors, multiple logistic regression analysis identified BNP ≥238 pg/ml (relative risk [RR] 11.6, p = 0.002) and nonuse of CCBs (RR 22.2, p = 0.0014) as independent risk factors for delayed recovery and leptosomic build (BMI <20 kg/m(2)) as an independent predictor of rapid recovery (RR 0.11, p = 0.02). In conclusion, BNP level, BMI, and use of CCBs are associated with recovery speed of LV systolic function in patients with TC.

Management of catecholamine-induced stunned myocardium--a case report

Hypertensive, hypervolumic, and hemodilution therapy (triple-H therapy) is administered to patients with symptomatic cerebral vasospasm after intracranial aneurysm clipping. This therapy can sometimes result in cardiac dysfunction because of pharmacologically induced hyperadrenergic state. The diagnosis may be missed if blood pressure alone is monitored to guide triple-H therapy. In this report, we describe one such patient who developed cardiac failure after triple-H therapy. This was diagnosed by using a bioreactance noninvasive cardiac output monitoring. Continuous cardiac output monitoring by this technique facilitated treatment of cardiac failure with milrinone and dobutamine. At discharge, the patient had no neurologic deficits.

Natural history of cardiac arrest in patients with takotsubo cardiomyopathy

Cardiac arrest (CA) is relatively rare but lethal complication of takotsubo cardiomyopathy (TTC). In most instances, patients are diagnosed with TTC after CA, making it difficult to distinguish if TTC is the precipitant or the consequence of the index event. In this systematic review, patient-level data were obtained to seek out the characteristics of patients in whom the underlying cause of CA is TTC. A comprehensive search of 4 major databases (Embase, Ovid MEDLINE, PubMed, and Google Scholar) was performed from their inception to the last week of September 2014. Of 186 citations, 62 case studies were included in the analysis, providing patient-level data on 77 patients. In 60 patients (78%), the diagnosis of TTC was made after CA. Patients presenting with CA were younger (mean age 49.5 ± 16 vs 64.9 ± 11 years, p <0.0001) and had relatively shorter corrected QT interval (mean 530 ± 101 vs 616 ± 140 ms) on electrocardiography. TTC-related hypotension was the major cause of CA in the acute phase, while a long corrected QT interval triggered CA in the subacute (24- to 72-hour) phase. In 11 patients, CA was not directly instigated by TTC despite a left ventricular appearance matching TTC. In conclusion, in TTC, CA typically develops within the first 3 days of presentation and is the result of long corrected QT interval-induced polymorphic ventricular tachycardia. Secondary TTC, in which patients present with typical left ventricular features after CA, likely represents a distinct cohort in which identifiable inheritable arrhythmias or structural heart disease should be sought.

Epidemiology and pathophysiology of Takotsubo syndrome

Takotsubo syndrome is an acute cardiac syndrome first described in 1990 and characterized by transient left ventricular dysfunction affecting more than one coronary artery territory, often in a circumferential apical, mid-ventricular, or basal distribution. Several pathophysiological explanations have been proposed for this syndrome and its intriguing appearance, and awareness is growing that these explanations might not be mutually exclusive. The reversible apical myocardial dysfunction observed might result from more than one pathophysiological phenomenon. The pathophysiology of Takotsubo syndrome is complex and integrates neuroendocrine physiology, potentially involving the cognitive centres of the brain, and including the hypothalamic-pituitary-adrenal axis. Cardiovascular responses are caused by the sudden sympathetic activation and surge in concentrations of circulating catecholamines. The multiple morphological changes seen in the myocardium match those seen after catecholamine-induced cardiotoxicity. The acute prognosis and recurrence rate are now known to be worse than initially thought, and much still needs to be learned about the epidemiology and the underlying pathophysiology of this fascinating condition in order to improve diagnostic and treatment pathways.

The microbiome mutiny hypothesis: can our microbiome turn against us when we are old or seriously ill?

Background

The symbiotic organisms of the healthy microbiome tend to be harmless or even beneficial for the host; however, some symbionts are able to adjust their virulence in response to external stimuli. Evolutionary theory suggests that optimal virulence might increase if the mortality of the host (from unrelated causes) increases.

Presentation of the hypothesis

We hypothesize that microorganisms of the human microbiome may be capable of a coordinated phenotypic switch to higher virulence (“microbiome mutiny”) in old or seriously ill people, to optimize their transmission under the conditions of increased background mortality. This proposed virulence shift might contribute to the death of old or seriously ill people even in the absence of apparent disease.

Testing the hypothesis

Testable predictions of the hypothesis include increased expression of virulence factors in isolates of the same species of the microbiome obtained from ailing/old versus healthy/young individuals, and the existence of microbial mechanisms to assess the general condition (background mortality) of the host. Such tests are going to be important to distinguish the cases of “microbiome mutiny” from the situation where opportunistic infections or increased effective virulence arise from relaxed immune control in ailing or old individuals in the absence of changes in the symbionts/pathogens.

Implications of the hypothesis

Elucidating this potential mechanism might open up new possibilities for the clinical management of age related health issues and critical injuries or disease. Targeted prophylaxis against the microbes capable of virulence shifts could break the harmful feedback loop between deteriorating health and the “mutiny” of the microbiome.

Reviewers

This article was reviewed by Eugene V Koonin, Neil Greenspan and Michael Gilchrist.

Computational modeling of Takotsubo cardiomyopathy: effect of spatially varying β-adrenergic stimulation in the rat left ventricle

In Takotsubo cardiomyopathy, the left ventricle shows apical ballooning combined with basal hypercontractility. Both clinical observations in humans and recent experimental work on isolated rat ventricular myocytes suggest the dominant mechanisms of this syndrome are related to acute catecholamine overload. However, relating observed differences in single cells to the capacity of such alterations to result in the extreme changes in ventricular shape seen in Takotsubo syndrome is difficult. By using a computational model of the rat left ventricle, we investigate which mechanisms can give rise to the typical shape of the ventricle observed in this syndrome. Three potential dominant mechanisms related to effects of β-adrenergic stimulation were considered: apical-basal variation of calcium transients due to differences in L-type and sarco(endo)plasmic reticulum Ca²⁺-ATPase activation, apical-basal variation of calcium sensitivity due to differences in troponin I phosphorylation, and apical-basal variation in maximal active tension due to, e.g., the negative inotropic effects of p38 MAPK. Furthermore, we investigated the interaction of these spatial variations in the presence of a failing Frank-Starling mechanism. We conclude that a large portion of the apex needs to be affected by severe changes in calcium regulation or contractile function to result in apical ballooning, and smooth linear variation from apex to base is unlikely to result in the typical ventricular shape observed in this syndrome. A failing Frank-Starling mechanism significantly increases apical ballooning at end systole and may be an important additional factor underpinning Takotsubo syndrome.

Induced effects of transcranial magnetic stimulation on the autonomic nervous system and the cardiac rhythm

Several standard protocols based on repetitive transcranial magnetic stimulation (rTMS) have been employed for treatment of a variety of neurological disorders. Despite their advantages in patients that are retractable to medication, there is a lack of knowledge about the effects of rTMS on the autonomic nervous system that controls the cardiovascular system. Current understanding suggests that the shape of the so-called QRS complex together with the size of the different segments and intervals between the PQRST deflections of the heart could predict the nature of the different arrhythmias and ailments affecting the heart. This preliminary study involving 10 normal subjects from 20 to 30 years of age demonstrated that rTMS can induce changes in the heart rhythm. The autonomic activity that controls the cardiac rhythm was indeed altered by an rTMS session targeting the motor cortex using intensity below the subject's motor threshold and lasting no more than 5 minutes. The rTMS activation resulted in a reduction of the RR intervals (cardioacceleration) in most cases. Most of these cases also showed significant changes in the Poincare plot descriptor SD2 (long-term variability), the area under the low frequency (LF) power spectrum density curve, and the low frequency to high frequency (LF/HF) ratio. The RR intervals changed significantly in specific instants of time during rTMS activation showing either heart rate acceleration or heart rate deceleration.

Takotsubo cardiomyopathy and anaesthesia: case report and review of the literature

Takotsubo cardiomyopathy is an acute syndrome characterized by cardiac failure from disturbances in the contractility of the left ventricle. It is presumably caused by sympathetic over stimulation. We describe a case of postoperatively developed Takotsubo cardiomyopathy in a 69-year-old female. The syndrome developed in connection with awareness during complete residual paralysis. The literature on this syndrome is reviewed and implications for anaesthesia described.

Takotsubo cardiomyopathy a short review

Takotsubo cardiomyopathy (TCM), otherwise cardiomyopathy,apical ballooning syndrome or broken heart syndrome is a reversible cardiomyopathy, predominantly occurs in post-menopausal women and commonly due to emotional or physical stress. Typically, patients present with chest pain and ST elevation or T wave inversion on their electrocardiogram mimicking acute coronary syndrome, but with normal or non-flow limiting coronary artery disease. Acute dyspnoea, hypotension and even cardiogenic shock may be the presenting feature of this condition. The wall motion abnormalities typically involve akinesia of the apex of the left ventricle with hyperkinesia of the base of the heart. Atypical forms of TCM have also recently been described. An urgent left ventriculogram or echocardiogram is the key investigation to identify this syndrome. Characteristically, there is only a limited release of cardiac enzymes disproportionate to the extent of regional wall motion abnormality. Transient right ventricular dysfunction may occur and is associated with more complications, longer hospitalisation and worse left ventricular systolic dysfunction. Recently, cardiac MRI has been increasingly used to diagnose this condition and to differentiate from acute coronary syndrome in those who have abnormal coronary arteries. Treatment is often supportive, however beta-blocker and angiotensin-converting enzyme inhibitor or angiotensin II receptor blocking agent are being used in routine clinical practice. The syndrome is usually spontaneously reversible and cardiovascular function returns to normal after a few weeks. This review article will elaborate on the pathophysiology, clinical features including the variant forms, latest diagnostic tools, management and prognosis of this condition.

Brain-heart crosstalk: the many faces of stress-related cardiomyopathy syndromes in anaesthesia and intensive care

Neurogenic stress cardiomyopathy (NSC) is a well-known syndrome complicating the early phase after an acute brain injury, potentially affecting outcomes. This article is a review of recent data on the putative role of localization and lateralization of brain lesions in NSC, cardiac innervation abnormalities, and new polymorphisms and other genetic causes of the sympathetic nervous system over-activity. Concerns regarding the management of stress-related cardiomyopathy syndromes during the perioperative period are also discussed. Future clinical research should explore whether specific factors explain different patient susceptibilities to the disease and should be directed towards early identification and stratification of patients at risk, so that such patients can be more carefully monitored and appropriately managed in critical care and during the perioperative period.

Clinical characteristics of myocardial stunning in acute stroke

Neurogenic stunned myocardium (NSM) after subarachnoid hemorrhage (SAH) is well known, but there is a paucity of data regarding its occurrence following acute stroke. The aim of this study is to investigate the clinical characteristics of NSM in acute non-hemorrhagic stroke. We performed an electronic literature search with Medline and Google Scholar for English-language articles using the terms "ischemic stroke" along with "stunned myocardium" or "Takotsubo cardiomyopathy". The search resulted in seven case reports/series, but no prospective studies. The mean age of patients with myocardial stunning following ischemic stroke was 72.5 years and 77% of these patients were females. Insular cortex was involved in 38.4% of cases. Mean National Institutes of Health Stroke Scale (NIHSS) score at admission was 12.6 and mean NIHSS at discharge was 10.8. T-wave inversions and ST-segment elevations were noted in 84.6% and 69.2% of patients, respectively. Mean troponin elevation was 0.64 mcg/dL and mean left ventricular ejection fraction (LVEF) was 34.4%. In terms of outcomes, 84.6% of patients had significant improvement in LVEF, mostly within 4 weeks of onset of symptoms. To summarize, NSM was more common in females, with favorable prognosis. Less than half the patients with NSM following stroke had insular involvement. The mean troponin level in NSM after stroke was only half of that seen in SAH. While the lack of prospective studies on NSM in stroke patients precludes drawing further conclusions, more studies are warranted to investigate the risk factors for NSM and the effect on stroke outcomes.

Mechanisms of stress (takotsubo) cardiomyopathy

Stress cardiomyopathy is a form of reversible systolic dysfunction of the mid and apical left ventricle with pathologic changes of the electrocardiogram in the absence of an obstructive coronary artery disease. The prevalence of stress cardiomyopathy among patients with symptoms suggestive of myocardial infarction is 0.7% to 2.5%, and it is found predominantly in postmenopausal women (90%). No large studies have confirmed the cause of stress cardiomyopathy. Published data suggest that substantially elevated plasma catecholamine levels, due to emotional or physical stress, may be relevant.