Takotsubo syndrome (TKS): A possible mechanism of sudden unexplained death in epilepsy (SUDEP)

Characteristics of deceased subjects transported to a postmortem imaging center due to unusual death related to epilepsy

OBJECTIVE

Patients with epilepsy have high risk of experiencing uncommon causes of death. This study aimed to evaluate patients who underwent unusual deaths related to epilepsy and identify factors that may contribute to these deaths and may also include sudden unexpected death in epilepsy (SUDEP).

METHODS

We analyzed 5291 cases in which a postmortem imaging (PMI) study was performed using plane CT, because of an unexplained death. A rapid troponin T assay was performed using peripheral blood samples. Clinical information including the cause of death suspected by the attending physician, body position, place of death, medical history, and antiseizure medications was evaluated.

RESULTS

A total of 132 (2.6%) patients had an obvious history of epilepsy, while 5159 individuals had no history of epilepsy (97.4%). Cerebrovascular disease was the cause of death in 1.6% of patients in the group with epilepsy, and this was significantly lower than that in the non-epilepsy group. However, drowning was significantly higher (9.1% vs. 4.4%). Unspecified cause of death was significantly more frequent in the epilepsy group (78.0% vs. 57.8%). Furthermore, the proportion of patients who demonstrated elevation of troponin T levels without prior cardiac disease was significantly higher in the epilepsy group (37.9% vs. 31.1%). At discovery of death, prone position was dominant (30.3%), with deaths occurring most commonly in the bedroom (49.2%). No antiseizure medication had been prescribed in 12% of cases, while 29.5% of patients were taking multiple antiseizure medications.

SIGNIFICANCE

The prevalence of epilepsy in individuals experiencing unusual death was higher than in the general population. Despite PMI studies, no definitive cause of death was identified in a significant proportion of cases. The high troponin T levels may be explained by long intervals between death and examination or by higher incidence of myocardial damage at the time of death.

PLAIN LANGUAGE SUMMARY

This study investigated unusual deaths in epilepsy patients, analyzing 5291 postmortem imaging cases. The results showed that 132 cases (2.6%) had a clear history of epilepsy. In these cases, only 22% cases were explained after postmortem examination, which is less than in non-epilepsy group (42.2%). Cerebrovascular disease was less common in the epilepsy group, while drowning was more common. Elevated troponin T levels, which suggest possibility of myocardial damage or long intervals between death and examination, were also more frequent in the epilepsy group compared to non-epilepsy group.

Takotsubo Syndrome and Sudden Cardiac Death

Takotsubo syndrome (TTS), triggered by intense emotional or physical stress, occurring most commonly in post-menopausal women, presents as an ST-elevation myocardial infarction (MI). Cardiovascular complications occur in almost half the patients with TTS, and the inpatient mortality is comparable to MI (4-5%) owing to cardiogenic shock, myocardial rupture, or life-threatening arrhythmias. Thus, its prognosis is not as benign as previously thought, as it may cause mechanical complications (cardiac rupture) and potentially lethal arrhythmias and sudden cardiac death (SCD). Similar to MI, some patients may perish before reaching the hospital due to out-of-hospital cardiac arrest; this may lead to underestimation of the actual SCD risk. Furthermore, after discharge, some patients may develop late SCD and/or TTS recurrence that may result in SCD. There are risk factors for SCD in TTS patients, such as severe/persistent QT-interval prolongation inciting torsade-de-pointes, other ECG abnormalities (diffuse giant negative T-waves, widened QRS-complex), bradyarrhythmias, comorbidities, concurrent obstructive coronary artery disease or vasospasm, male gender, older age, severe left ventricular dysfunction, and use of sympathomimetic drugs. All these issues are herein reviewed, case reports/series and data from large cohort studies and meta-analyses are analyzed, risk factors are tabulated, and proarrhythmic effects and management strategies are discussed and pictorially illustrated.

Sudden Unexpected Death in Epilepsy

Epilepsy is a complex neurological condition with numerous etiologies and treatment options. In a subset of these patients, sudden unexpected death can occur, and to date, there are numerous explanations as to the pathophysiological mechanisms and how to mitigate these catastrophic outcomes. Approximately 2.3 million Americans have epilepsy, and nearly 150,000 people develop the condition each year. Sudden unexpected death in epilepsy (SUDEP) accounts for 2–18% of all epilepsy-related deaths and this is equivalent to one death in 1000 person-years of diagnosed epilepsy. It is more common in young adults aged 20–45. Seizures in the past year; the absence of terminal remission in the last five years; increased seizure frequency, particularly GTCS; and nocturnal seizures are the most potent modifiable risk factors for SUDEP. Patients not receiving any antiepileptic drug therapy are at higher risk of SUDEP. Patient education on medication compliance; care plans for seizure clusters (rescue medicines); epilepsy self-management programs; and lifestyle changes to avoid seizure-triggering factors, including avoiding excessive alcohol use and sleep deprivation, should be provided by health care providers. Continued research into SUDEP will hopefully lead to effective interventions to minimize occurrences. At present, aggressive control of epilepsy and enhanced education for individuals and the public are the most effective weapons for combating SUDEP. This narrative review focuses on updated information related to SUDEP epidemiology; pathophysiology; risk factor treatment options; and finally, a discussion of important clinical studies. We seek to encourage clinicians who care for patients with epilepsy to be aggressive in controlling seizure activity and diligent in their review of risk factors and education of patients and their families about SUDEP.

Cardiac Dysfunction in a Mouse Vascular Dementia Model of Bilateral Common Carotid Artery Stenosis

Background: Cardiac function is associated with cognitive function. Previously, we found that stroke and traumatic brain injury evoke cardiac dysfunction in mice. In this study, we investigate whether bilateral common carotid artery stenosis (BCAS), a model that induces vascular dementia (VaD) in mice, induces cardiac dysfunction. Methods: Late-adult (6-8 months) C57BL/6J mice were subjected to sham surgery (n = 6) or BCAS (n = 8). BCAS was performed by applying microcoils (0.16 mm internal diameter) around both common carotid arteries. Cerebral blood flow and cognitive function tests were performed 21-28 days post-BCAS. Echocardiography was conducted in conscious mice 29 days after BCAS. Mice were sacrificed 30 days after BCAS. Heart tissues were isolated for immunohistochemical evaluation and real-time PCR assay. Results: Compared to sham mice, BCAS in mice significantly induced cerebral hypoperfusion and cognitive dysfunction, increased cardiac hypertrophy, as indicated by the increased heart weight and the ratio of heart weight/body weight, and induced cardiac dysfunction and left ventricular (LV) enlargement, indicated by a decreased LV ejection fraction (LVEF) and LV fractional shortening (LVFS), increased LV dimension (LVD), and increased LV mass. Cognitive deficits significantly correlated with cardiac deficits. BCAS mice also exhibited significantly increased cardiac fibrosis, increased oxidative stress, as indicated by 4-hydroxynonenal and NADPH oxidase-2, increased leukocyte and macrophage infiltration into the heart, and increased cardiac interleukin-6 and thrombin gene expression. Conclusions: BCAS in mice without primary cardiac disease provokes cardiac dysfunction, which, in part, may be mediated by increased inflammation and oxidative stress.

The Epileptic Heart: Concept and clinical evidence

Sudden unexpected death in epilepsy (SUDEP) is generally considered to result from a seizure, typically convulsive and usually but not always occurring during sleep, followed by a sequence of events in the postictal period starting with respiratory distress and progressing to eventual cardiac asystole and death. Yet, recent community-based studies indicate a 3-fold greater incidence of sudden cardiac death in patients with chronic epilepsy than in the general population, and that in 66% of cases, the cardiac arrest occurred during routine daily activity and without a temporal relationship with a typical seizure. To distinguish a primarily cardiac cause of death in patients with epilepsy from the above description of SUDEP, we propose the concept of the "Epileptic Heart" as "a heart and coronary vasculature damaged by chronic epilepsy as a result of repeated surges in catecholamines and hypoxemia leading to electrical and mechanical dysfunction." This review starts with an overview of the pathophysiological and other lines of evidence supporting the biological plausibility of the Epileptic Heart, followed by a description of tools that have been used to generate new electrocardiogram (EKG)-derived data in patients with epilepsy that strongly support the Epileptic Heart concept and its propensity to cause sudden cardiac death in patients with epilepsy independent of an immediately preceding seizure.

Let's talk SUDEP

Sudden unexplained death in epilepsy (SUDEP) is a devastating complication of epilepsy which was under-recognized in the recent past despite its clear importance. In this review, we examine the definition of SUDEP, revise current pathophysiological theories, discuss risk factors and preventative measures, disclose tools for appraising the SUDEP risk, and last but not least dwell upon announcing and explaining the SUDEP risk to the patients and their caretakers. We aim to aid the clinicians in their responsibility of knowing SUDEP, explaining the SUDEP risk to their patients in a reasonable and sensible way and whenever possible, preventing SUDEP. Future studies are definitely needed to increase scientific knowledge and awareness related to this prioritized topic with malign consequences.

Immediate versus delayed detection of Takotsubo syndrome after epileptic seizures

Takotsubo syndrome(TTS) is often preceded by emotional or physical stress. Epileptic seizures are described in >100 cases. It is unknown whether patients with immediate and delayed detection of seizure-induced TTS differ. We screened the literature and compared clinical and electrocardiographic (ECG) findings. In 48 cases with seizure-associated TTS, the time between seizure and TTS-detection was reported. Troponin levels were elevated in 37/40. ECG abnormalities were negative T-waves(40%), ST-elevations(33%) and ventricular fibrillation/flutter(10%). Immediate detection was reported in 23 patients, in the remaining 25 patients, TTS was detected 5-288 h postictally. Patients did not differ in gender, age or symptoms. Negative T-waves were more frequent in patients with delayed detection(64 vs. 13%, p = .0009), whereas ECG-abnormalities suggesting acute myocardial infarction tended to be more prevalent in patients with immediate detection. Due to lack of typical symptoms, seizure-induced TTS can be overlooked. Postictally, an ECG should be recorded and troponin levels measured. New T-wave inversions might indicate seizure-induced TTS.

Acute Cardiac Complications in Critical Brain Disease

Acute cardiac complications in critical brain disease should be understood as a clinical condition representing an intense brain-heart crosstalk and might mimic ischemic heart disease. Two main entities (neurogenic stunned myocardium [NSM] and stress cardiomyopathy) have been better characterized in the neurocritically ill patients and they portend worse clinical outcomes in these cases. The pathophysiology of NSM remains elusive. However, significant progress has been made on the early identification of neurocardiac compromise following acute critical brain disease. Effective prevention and treatment interventions are yet to be determined.

Acute Cardiac Complications in Critical Brain Disease

Acute cardiac complications in critical brain disease should be understood as a clinical condition representing an intense brain-heart crosstalk and might mimic ischemic heart disease. Two main entities (neurogenic stunned myocardium [NSM] and stress cardiomyopathy) have been better characterized in the neurocritically ill patients and they portend worse clinical outcomes in these cases. The pathophysiology of NSM remains elusive. However, significant progress has been made on the early identification of neurocardiac compromise following acute critical brain disease. Effective prevention and treatment interventions are yet to be determined.

Identifying and mitigating Sudden Unexpected Death in Epilepsy (SUDEP) risk factors

INTRODUCTION

Sudden Unexpected Death in Epilepsy (SUDEP) is a significant cause of death for people with chronic epilepsy. Good practice guidance in the UK and the USA expect SUDEP to be discussed with the individual. The event rarity, methodological variance and lack of robust research into the pathological mechanisms, associated risk factors, and management strategies have created a challenge on how and what to discuss. There are some significant associations which allows for risk assessment and mitigation. Areas covered: The current understanding of static and modifiable risk factors for SUDEP and how to manage these more effectively are reviewed. Longitudinal risk may be assessed using standardised risk assessment tools which help in communicating risk. Technological advancement allows measurement of physiological parameters associated with seizures and risk of SUDEP using small wearable devices. Further evidence is needed to demonstrate such technologies are efficacious and safe. Expert commentary: Risk reduction should be an important part of epilepsy management and we suggest a Gold Standard of Care which healthcare professionals and services should aim for when approaching SUDEP risk management. A Minimum Standard of Care is also proposed that is practical to implement, that all people with epilepsy should expect to receive.

Pulmonary and cardiac pathology in sudden unexpected death in epilepsy (SUDEP)

OBJECTIVE

To review studies on structural pulmonary and cardiac changes in SUDEP cases as well as studies showing pulmonary or cardiac structural changes in living epilepsy patients.

METHODS

We conducted electronic literature searches using the PubMed database for articles published in English, regardless of publication year, that included data on cardiac and/or pulmonary structural abnormalities in SUDEP cases or in living epilepsy patients during the postictal period.

RESULTS

Fourteen postmortem studies reported pulmonary findings in SUDEP cases. Two focused mainly on assessing lung weights in SUDEP cases versus controls; no group difference was found. The other 12 reported descriptive autopsy findings. Among all SUDEP cases with available descriptive postmortem pulmonary examination, 72% had pulmonary changes, most often pulmonary edema/congestion, and, less frequently, intraalveolar hemorrhage. Eleven studies reported on cardiac pathology in SUDEP. Cardiac abnormalities were found in approximately one-fourth of cases. The most common findings were myocyte hypertrophy and myocardial fibrosis of various degrees. Among living epilepsy patients, postictal pulmonary pathology was the most commonly reported pulmonary abnormality and the most common postictal cardiac abnormality was transient left ventricular dysfunction - Takotsubo or neurogenic stunned myocardium.

SIGNIFICANCE

Cardiac and pulmonary pathological abnormalities are frequent among SUDEP cases, most commonly pulmonary edema/congestion and focal interstitial myocardial fibrosis. Most findings are not quantified, with subjective elements and undefined interobserver reliability, and lack of controls such as matched epilepsy patients who died from other causes. Further, studies have not systematically evaluated potential confounding factors, including postmortem interval to autopsy, paramedic resuscitation and IV fluids administration, underlying heart/lung disease, and risk factors for cardiac or pulmonary disease. Prospective studies with controls are needed to define the heart and lung changes in SUDEP and understand their potential relationship to mechanisms of death in SUDEP.

Heart-Brain Axis: Effects of Neurologic Injury on Cardiovascular Function

A complex interaction exists between the nervous and cardiovascular systems. A large network of cortical and subcortical brain regions control cardiovascular function via the sympathetic and parasympathetic outflow. A dysfunction in one system may lead to changes in the function of the other. The effects of cardiovascular disease on the nervous system have been widely studied; however, our understanding of the effects of neurological disorders on the cardiovascular system has only expanded in the past 2 decades. Various pathologies of the nervous system can lead to a wide range of alterations in function and structure of the cardiovascular system ranging from transient and benign electrographic changes to myocardial injury, cardiomyopathy, and even cardiac death. In this article, we first review the anatomy and physiology of the central and autonomic nervous systems in regard to control of the cardiovascular function. The effects of neurological injury on cardiac function and structure will be summarized, and finally, we review neurological disorders commonly associated with cardiovascular manifestations.

Recurrence of Postoperative Stress-Induced Cardiomyopathy Resulting from Status Epilepticus

Introduction. Classically, stress-induced cardiomyopathy (SIC), also known as takotsubo cardiomyopathy, displays the pathognomonic feature of reversible left ventricular apical ballooning without coronary artery stenosis following stressful event(s). Temporary reduction in ejection fraction (EF) resolves spontaneously. Variants of SIC exhibiting mid-ventricular regional wall motion abnormalities have been identified. Recent case series present SIC as a finding in association with sudden unexplained death in epilepsy (SUDEP). This case presents a patient who develops recurrence of nonapical cardiomyopathy secondary to status epilepticus. Case Report. Involving a postoperative, postmenopausal woman having two distinct episodes of status epilepticus (SE) preceding two incidents of SIC. Preoperative transthoracic echocardiogram (TTE) confirms the patient's baseline EF of 60% prior to the second event. Postoperatively, SE occurs, and the initial electrocardiogram exhibits T-wave inversions with subsequent elevation of troponin I. Postoperative TTE shows an EF of 30% with mid-ventricular wall akinesia restoring baseline EF rapidly. Conclusion. This case identifies the need to understand SIC and its diagnostic criteria, especially when cardiac catheterization is neither indicated nor available. Sudden cardiac death should be considered as a possible complication of refractory status epilepticus. The pathophysiology in SUDEP is currently unknown; yet a correlation between SUDEP and SIC is hypothesized to exist.

Neurocardiology

Neurocardiology refers to the interplay between the nervous system and the cardiovascular system. Stress-related cardiomyopathy exemplifies the brain-heart connection and occurs in several conditions with acute brain injury that share oversympathetic activation. The brain's influences on the heart can include elevated cardiac markers, arrhythmias, repolarization abnormalities on electrocardiogram, myocardial necrosis, and autonomic dysfunction. The neurogenic stunned myocardium in aneurysmal subarachnoid hemorrhage represents one end of the spectrum, and is associated with an explosive rise in intracranial pressure that results in excess catecholamine state and possibly CBN. A brain-heart link is more known to cardiologists than neurologists. This chapter provides some insight into the pathophysiology of these pathologic neurocardiac states and their most appropriate management relevant to neurologists.

Cardiac dysfunction following brain death after severe pediatric traumatic brain injury: A preliminary study of 32 children

Background:

Cardiac dysfunction after brain death has been described in a variety of brain injury paradigms but is not well understood after severe pediatric traumatic brain injury (TBI). Cardiac dysfunction may have implications for organ donation in this patient population.

Materials and Methods:

We conducted a retrospective cohort study of pediatric patients with severe TBI, both with and without a diagnosis of brain death, who underwent echocardiography during the first 2 weeks after TBI, between the period of 2003–2011. We examined cardiac dysfunction in patients with and without a diagnosis of brain death.

Results:

In all, 32 (2.3%) of 1,413 severe pediatric TBI patients underwent echocardiogram evaluation. Most patients had head abbreviated injury score 5 (range 2–6) and subdural hematoma (34.4%). Ten patients with TBI had brain death compared with 22 severe TBI patients who did not have brain death. Four (40%) of 10 pediatric TBI patients with brain death had a low ejection fraction (EF) compared with 1 (4.5%) of 22 pediatric TBI patients without brain death who had low EF (OR = 14, P = 0.024).

Conclusions:

The incidence of cardiac dysfunction is higher among pediatric severe TBI patients with a diagnosis of brain death, as compared to patients without brain death. This finding may have implications for cardiac organ donation from this population and deserves further study.

CNS disease triggering Takotsubo stress cardiomyopathy

There are a number of hereditary and non-hereditary central nervous system (CNS) disorders, which directly or indirectly affect the heart (brain-heart disorders). The most well-known of these CNS disorders are epilepsy, stroke, infectious or immunological encephalitis/meningitis, migraine, and traumatic brain injury. In addition, a number of hereditary and non-hereditary neurodegenerative disorders may impair cardiac functions. Affection of the heart may manifest not only as arrhythmias, myocardial infarction, autonomic impairment, systolic dysfunction/heart failure, arterial hypertension, or pulmonary hypertension, but also as stress cardiomyopathy (Takotsubo syndrome, TTS). CNS disease triggering TTS includes subarachnoid bleeding, epilepsy, ischemic stroke, intracerebral bleeding, migraine, encephalitis, traumatic brain injury, PRES syndrome, or ALS. Usually, TTS is acutely precipitated by stress triggered by various different events. TTS is one of the cardiac abnormalities most frequently induced by CNS disorders. Appropriate management of TTS from CNS disorders is essential to improve the outcome of affected patients.

Antiarrhythmic drugs and epilepsy

For a long time it has been suspected that epilepsy and cardiac arrhythmia may have common molecular background. Furthermore, seizures can affect function of the central autonomic control centers leading to short- and long-term alterations of cardiac rhythm. Sudden unexpected death in epilepsy (SUDEP) has most likely a cardiac mechanism. Common elements of pathogenesis create a basis for the assumption that antiarrhythmic drugs (AADs) may affect seizure phenomena and interact with antiepileptic drugs (AEDs). Numerous studies have demonstrated anticonvulsant effects of AADs. Among class I AADs (sodium channel blockers), phenytoin is an established antiepileptic drug. Propafenone exerted low anti-electroshock activity in rats. Lidocaine and mexiletine showed the anticonvulsant activity not only in animal models, but also in patients with partial seizures. Among beta-blockers (class II AADs), propranolol was anticonvulsant in models for generalized tonic-clonic and complex partial seizures, but not for myoclonic convulsions. Metoprolol and pindolol antagonized tonic-clonic seizures in DBA/2 mice. Timolol reversed the epileptiform activity of pentylenetetrazol (PTZ) in the brain. Furthermore, amiodarone, the representative of class III AADs, inhibited PTZ- and caffeine-induced convulsions in mice. In the group of class IV AADs, verapamil protected mice against PTZ-induced seizures and inhibited epileptogenesis in amygdala-kindled rats. Verapamil and diltiazem showed moderate anticonvulsant activity in genetically epilepsy prone rats. Additionally, numerous AADs potentiated the anticonvulsant action of AEDs in both experimental and clinical conditions. It should be mentioned, however, that many AADs showed proconvulsant effects in overdose. Moreover, intravenous esmolol and intra-arterial verapamil induced seizures even at therapeutic dose ranges.

Preliminary report on cardiac dysfunction after isolated traumatic brain injury

OBJECTIVE

The aim of this study was to examine cardiac dysfunction during the first 2 weeks after isolated traumatic brain injury and its association with in-hospital mortality.

DESIGN

Retrospective.

SETTING

Level 1 regional trauma center.

PATIENTS

Adult patients with severe traumatic brain injury.

METHODS

After institutional review board approval, data from adult patients with isolated traumatic brain injury who underwent echocardiography during the first 2 weeks after traumatic brain injury between 2003 and 2010 were examined. Patients with preexisting cardiac disease were excluded. Clinical characteristics and echocardiogram reports were abstracted. Cardiac dysfunction was defined as left ventricular ejection fraction less than 50% or presence of regional wall motion abnormality.

INTERVENTIONS

None.

MEASUREMENT AND MAIN RESULTS

We examined data from 139 patients with isolated traumatic brain injury who underwent echocardiographic evaluation. Patients were 58 ± 20 years old, 66% were male patients, and 62.6% had subdural hematoma; admission Glasgow Coma Scale score was 3 ± 1 (3-15) and head Abbreviated Injury Scale was 4 ± 1 (2-5). Of this cohort, 22.3% had abnormal echocardiogram: reduced left ventricular ejection fraction was documented in 12% (left ventricular ejection fraction, 43% ± 8%) and 17.5% of patients had a regional wall motion abnormality. Hospital day 1 was the most common day of echocardiographic exam. Abnormal echocardiogram was independently associated with all cause in-hospital mortality (9.6 [2.3-40.2]; p = 0.002).

CONCLUSIONS

Cardiac dysfunction in the setting of isolated traumatic brain injury occurs and is associated with increased in-hospital mortality. This finding raises the question as to whether there are uncharted opportunities for a more timely recognition of cardiac dysfunction and subsequent optimization of the hemodynamic management of these patients.

Neurogenic Stunned Myocardium Following Acute Subarachnoid Hemorrhage

Neurogenic stunned myocardium (NSM) is a triad of transient left ventricular dysfunction, electrocardiogram changes, and elevation in cardiac enzymes, often mimicking a myocardial infarction. It has been described following acute brain injury. The purported mechanism is catecholamine excess resulting in cardiac dysfunction. From the clinical standpoint, the most frequently encountered electrocardiographic changes are QTc prolongation and ST-T changes, with modest elevations in troponin levels. Basal and mid-ventricular segments of the left ventricle are most commonly involved. NSM poses therapeutic challenges when it occurs secondary to aneurysmal subarachnoid hemorrhage, particularly in the setting of coexisting vasospasm. Overall, NSM carries good prognosis if recognized early, with appropriate management of hemodynamic and cardiopulmonary parameters.

Potential links between neurological disease and Tako-Tsubo cardiomyopathy: a literature review

Tako-Tsubo cardiomyopathy (TTC), is defined as a fully reversible acute deterioration of left-ventricular (LV) function, which is mainly found in women after an episode of emotional or physical stress (e.g. psychosocial stress, sepsis, surgery). The underlying mechanisms remain unclear. There is evidence suggesting a possible link between neurological disease and TTC. The pathophysiology of the several neurologic diseases has been reviewed searching for possible mechanisms that could lead to TTC in these patients.