Effects of Seizures on Cardiac Function

Electrocardiogram Changes in the Postictal Phase of Epileptic Seizure: Results from a Prospective Study

BACKGROUND

The brain and heart are strictly linked and the electrical physiologies of these organs share common pathways and genes. Epilepsy patients have a higher prevalence of electrocardiogram (ECG) abnormalities compared to healthy people. Furthermore, the relationship between epilepsy, genetic arrhythmic diseases and sudden death is well known. The association between epilepsy and myocardial channelopathies, although already proposed, has not yet been fully demonstrated. The aim of this prospective observational study is to assess the role of the ECG after a seizure.

MATERIALS AND METHODS

From September 2018 to August 2019, all patients admitted to the emergency department of San Raffaele Hospital with a seizure were enrolled in the study; for each patient, neurological, cardiological and ECG data were collected. The ECG was performed at the time of the admission (post-ictal ECG) and 48 h later (basal ECG) and analyzed by two blinded expert cardiologists looking for abnormalities known to indicate channelopathies or arrhythmic cardiomyopathies. In all patients with abnormal post-ictal ECG, next generation sequencing (NGS) analysis was performed.

RESULTS

One hundred and seventeen patients were enrolled (females: 45, median age: 48 ± 12 years). There were 52 abnormal post-ictal ECGs and 28 abnormal basal ECGs. All patients with an abnormal basal ECG also had an abnormal post-ictal ECG. In abnormal post-ictal ECG, a Brugada ECG pattern (BEP) was found in eight patients (of which two had BEP type I) and confirmed in two basal ECGs (of which zero had BEP type I). An abnormal QTc interval was identified in 20 patients (17%), an early repolarization pattern was found in 4 patients (3%) and right precordial abnormalities were found in 5 patients (4%). Any kind modification of post-ictal ECG was significantly more pronounced in comparison with an ECG recorded far from the seizure (p = 0.003). A 10:1 higher prevalence of a BEP of any type (particularly in post-ictal ECG, p = 0.04) was found in our population compared to general population. In three patients with post-ictal ECG alterations diagnostic for myocardial channelopathy (BrS and ERP), not confirmed at basal ECG, a pathogenic gene variant was identified (KCNJ8, PKP2 and TRMP4).

CONCLUSION

The 12-lead ECG after an epileptic seizure may show disease-related alterations otherwise concealed in a population at a higher incidence of sudden death and channelopathies. Post-ictal BEP incidence was higher in cases of nocturnal seizure.

Protocols for multimodal polygraphy for cardiorespiratory monitoring in the epilepsy monitoring unit. Part I: Clinical acquisition

Multimodal polygraphy including cardiorespiratory monitoring in the Epilepsy Monitoring is becoming increasingly important. In addition to simultaneous recording of video and EEG, the combination of these techniques not only improves seizure detection, it enhances patient safety and provides information on autonomic clinical symptoms, which may be contributory to localization of seizure foci. However, there are currently no consensus guidelines, nor adequate information on devices available for multimodal polygraphy for cardiorespiratory monitoring in the Epilepsy Monitoring Unit. Our purpose here is to provide protocols and information on devices for such monitoring. Suggested parameters include respiratory inductance plethysmography (thoraco-abdominal belts for respiratory rate), pulse oximetry and four-lead electrocardiography. Detailed knowledge of devices, their operability and acquisition optimization enables accurate interpretation of signal and differentiation of abnormalities from artifacts. Multimodal polygraphy brings new opportunities for identification of peri-ictal cardiorespiratory abnormalities, and may identify high SUDEP risk individuals.

Sudden Death and Cardiac Arrythmia With Lamotrigine: A Rapid Systematic Review

BACKGROUND AND OBJECTIVES

A recent Food and Drug Administration warning concerning an arrhythmogenic potential of lamotrigine created concern in the neurologic community. This warning was based on in vitro studies, but no clinically relevant risk was considered. This rapid systematic review aims to elucidate the risk of lamotrigine on sudden death or ECG abnormalities.

METHODS

We conducted a systematic search of Ovid Medline and Ovid Embase, including randomized controlled trials and observational studies and studies of people with or without epilepsy, with the outcome measures sudden unexpected death in epilepsy (SUDEP) or sudden cardiac death as well as the development or worsening of ECG abnormalities. We evaluated the sudden death definitions used in all included studies, as some could have used unclear or overlapping definitions. We used the American Academy of Neurology risk of bias tool to evaluate the class of evidence and the GRADE approach to evaluate our confidence in the evidence.

RESULTS

We included 26 studies with 24,962 participants, of whom 2,326 used lamotrigine. Twelve studies showed no significant risk of SUDEP for lamotrigine users. One study reporting on sudden cardiac death and 3 studies with unclear sudden death definitions did not report an elevated risk of death in lamotrigine users compared to controls. In 10 studies reporting on ECG measures, there was no statistically significant increased risk among lamotrigine users except in 2 studies. These 2 studies reported either "slight increases" in PR interval or an increased PQ interval that the primary study authors believed to be related to structural cardiac differences rather than an effect of lamotrigine. One study was rated Class II; all others were Class III or IV. We had very low confidence in the evidence following the GRADE assessment. None of the studies examined the risk of lamotrigine in people with preexisting cardiac conditions.

DISCUSSION

There is insufficient evidence to support or refute that lamotrigine is associated with sudden death or ECG changes in people with or without epilepsy as compared to antiseizure medication or placebo, due to the high risk of bias in most studies and low precision and inconsistency in the reported results.

Readmission for cardiac and non-cardiac causes among adults with epilepsy or multiple sclerosis - A nationwide analysis

PURPOSE

The aim of this study was to determine proportions of 30-day cardiac readmissions in adults with epilepsy compared to multiple sclerosis (MS) or those with neither condition. Predictors and causes of readmissions were also examined.

METHODS

We used the 2014 Nationwide Readmissions Database and ICD-9-CM codes to identify people with epilepsy, MS, and without epilepsy or MS. Multinomial logistic regressions were fitted to: (1) examine association between 30-day readmissions and epilepsy, MS or neither, and (2) to describe causes and predictors of 30-day readmission for cardiac readmissions in epilepsy.

RESULTS

Out of 6,870,508 adults admitted in 2014, 202,938 (2.98%) had epilepsy and 29,556 (0.45%) had MS. The proportion of 30-day readmission for epilepsy and MS were, respectively: (1) due to cardiac causes (0.17% vs. 0.13%); (2) due to other causes (13.89% vs. 10.61%). The odds of 30-day cardiac readmission in those with epilepsy and MS were lower compared to those without either condition (OR = 0.64, 95% CI 0.57-0.73, p < 0.0001; OR = 0.60, 95% CI 0.43-0.84, p = 0.003). Among those with epilepsy, increasing age (OR = 1.03, 95% CI 1.02-1.04, p < 0.0001) and a Charlson comorbidity index ≥1 (OR = 1.79, 95% CI 1.24-2.60, p = 0.002) were associated with higher odds of 30-day cardiac readmission. A higher proportion of those with epilepsy readmitted within 30-days due to cardiac causes died in hospital (10.09%) compared to those with MS (not reportable due to cell frequency <10) or without epilepsy or MS (5.61%).

CONCLUSION

Those admitted to a hospital and living with epilepsy had a higher proportion of cardiac readmissions and death in hospital when compared to those living with MS, and the determinants are likely multifactorial. These findings are important and need to be further explored to identify strategies to prevent readmissions due to any cause and treatments that could reduce mortality.

Synergistic effect of sleep depth and seizures correlates with postictal heart rate

Our objective was to determine the effect of sleep on heart rate following a recorded seizure. We prospectively acquired heart rate data in hospitalized epilepsy monitoring unit patients. We analyzed heart rate trends for multiple seizures (n = 101) in patients (n = 42) with electroencephalographically confirmed events. The patient's sleep state was scored for the 5 min preceding each seizure and correlated with the postictal nadir heart rate (PINHR). The depth of sleep during the 5 min before a seizure correlated (correlation coefficient [CC] = -.229, p < .05) with PINHR. This result was more significant and strengthened (CC = -.272, 95% confidence interval = -.392 to -.152, p < .001) when adjusted for covariates of age, generalized tonic-clonic seizures, and baseline heart rate. Sleep depth is an independent predictor of the change in heart rate following a seizure. Diminished heart rate following a seizure in the setting of sleep is likely secondary to non-rapid eye movement sleep's synergistic effect on parasympathetic tone.

Risk of Cardiac Morbidities and Sudden Death in Patients With Epilepsy and No History of Cardiac Disease: A Population-Based Nationwide Study

OBJECTIVE

To investigate the impact of epilepsy on secondary cardiac morbidities and sudden death in patients with epilepsy.

PATIENTS AND METHODS

The present cohort study evaluated data obtained from a subset of adult patients listed in the Taiwan National Health Insurance Research Database with an International Classification of Diseases, Ninth Revision, diagnosis code of epilepsy from January 1, 1997, to December 31, 2013; the date of epilepsy diagnosis or antiepilepsy drug prescription was defined as the index date. Patients with cardiac disease prior to the index date were excluded, and the remaining patients were categorized into epilepsy and nonepilepsy groups. Frequency matching was performed to balance the covariates across groups for the comparison of outcomes. The development of myocardial infarction (MI) and arrhythmia and/or the occurrence of sudden death were the outcomes for evaluation. A Cox proportional hazards regression model and competing risk analysis were used to compare the risks of cardiac morbidities and sudden death between groups.

RESULTS

The final analysis included a total of 5411 patients with epilepsy and 21,644 participants without epilepsy. The epilepsy group had significantly higher risks for development of MI (hazard ratio [HR], 1.71; 95% CI, 1.62 to 1.81; P<.001) and arrhythmia (HR, 2.11; 95% CI, 1.97 to 2.25; P<.001) and the occurrence of sudden death (HR, 1.83; 95% CI, 1.53 to 2.18; P<.001) compared with the nonepilepsy group.

CONCLUSION

Our results indicate that the risks for development of MI and arrhythmia and the occurrence of sudden death were higher in patients with epilepsy. These findings support the hypothesis that epilepsy may lead to secondary cardiac dysfunction and increases the risk of sudden death.

Children with refractory epilepsy demonstrate alterations in myocardial strain

OBJECTIVE

To test whether children with epilepsy have impairments in myocardial mechanics compared to controls without epilepsy.

METHODS

Children with refractory epilepsy with epilepsy duration of at least 3 years underwent echocardiography including conventional measurements and speckle tracking to assess longitudinal and circumferential strain. Parent-completed surveys, capturing critical aspects of the children's seizure history and cardiac risk factors, complemented retrospective chart reviews, which also included antiepileptic drug history. Normal echocardiograms from controls, matched for age and gender, were obtained from our institutional database and evaluated for strain.

RESULTS

Forty-one patients (median age = 10 years, interquartile range [IQR] = 5-15; 58.5% male) were enrolled. Epilepsy etiology included genetic (n = 26), structural (n = 6), genetic and structural (n = 5), infection (n = 3), and unknown (n = 1). No cardiac structural abnormalities were identified. Both longitudinal and circumferential strain were impaired (P < .03) in patients compared to controls (median [IQR] = 22.7% [21.2-24.2] vs 23.6% [22.2-26.1] and 22.0% [20.3-25.4] vs 24.5% [22.3-27.0], respectively), indicating decreased myocardial deformation/contraction. Shortening fraction was higher in patients (37.6% [35.7-39.7] vs 34.9% [32.5-38.7], P = .009); mitral valve E wave inflow velocity (84.8 cm/s [78.4-92.8] vs 97.2 cm/s [85.9-105.8], P = .005) and tissue Doppler lateral E' wave (13.9 cm/s [12.3-16.1] vs 17.3 cm/s [15.4-18.5], P < .001) were decreased compared to controls. Findings were similar in the pairs with epilepsy patients distinguished by the ability to independently ambulate. There was no difference between patients and controls in ejection fraction. Among the epilepsy patients, there were no associations between cardiac measurements and epilepsy characteristics, including seizure type and frequency and cardiotoxic antiseizure medication exposure after correction for multiple comparisons.

SIGNIFICANCE

Children with refractory epilepsy had impaired systolic ventricular strain compared to controls, not correlated with epilepsy history. Further studies are needed to determine the significance of these changes.

[Sudden unexpected death in epilepsy (SUDEP) : Epidemiology, cardiac and other risk factors]

Sudden unexpected death in epilepsy (SUDEP) is one of the most frequent epilepsy-related causes of death. The incidence of SUDEP is estimated to be approximately 1.2/1000 person-years (PY); however, it varies considerably depending on disease-specific and demographic factors. The estimated incidence of SUDEP in children seems to be significantly lower (0.22/1000 PY) than in adults but recent studies in children (>12 years) indicated a similar incidence to that of adults. Based on these estimations, approximately 700 SUDEP cases would be expected in Germany annually but no reliable data or epidemiological studies on SUDEP are available. Various risk factors and predictors for SUDEP have been investigated, e.g. age, seizure frequency, number of antiepileptic drugs, non-compliance and comorbidities, with sometimes contradictory results. This is understandable given that the exact mechanisms of SUDEP are unclear; however, it is very likely that the frequency of (nocturnal) generalized tonic-clonic seizures is the most important risk factor. Nocturnal monitoring of seizures (using devices) or the presence of another person at night may represent important factors to reduce the risk of SUDEP. Thus, seizure control and seizure monitoring are, according to current knowledge, the most important factors to avoid SUDEP. Some recent studies have contributed to a better understanding of possible pathomechanisms of SUDEP; however, further research is needed to identify predictive clinical factors and biomarkers and in particular to prevent SUDEP.

Review: The past, present and future challenges in epilepsy-related and sudden deaths and biobanking

Awareness and research on epilepsy-related deaths (ERD), in particular Sudden Unexpected Death in Epilepsy (SUDEP), have exponentially increased over the last two decades. Most publications have focused on guidelines that inform clinicians dealing with these deaths, educating patients, potential risk factors and mechanisms. There is a relative paucity of information available for pathologists who conduct these autopsies regarding appropriate post mortem practice and investigations. As we move from recognizing SUDEP as the most common form of ERD toward in-depth investigations into its causes and prevention, health professionals involved with these autopsies and post mortem procedure must remain fully informed. Systematizing a more comprehensive and consistent practice of examining these cases will facilitate (i) more precise determination of cause of death, (ii) identification of SUDEP for improved epidemiological surveillance (the first step for an intervention study), and (iii) biobanking and cell-based research. This article reviews how pathologists and healthcare professionals have approached ERD, current practices, logistical problems and areas to improve and harmonize. The main neuropathology, cardiac and genetic findings in SUDEP are outlined, providing a framework for best practices, integration of clinical, pathological and molecular genetic investigations in SUDEP, and ultimately prevention.

An explanation for sudden death in epilepsy (SUDEP)

This review traces the examination of autonomic, cardiovascular, and respiratory derangements associated with seizure activity in the clinical and preclinical literature generally, and in the author's animal model specifically, and concludes with the author's views on the potential mechanisms for sudden death in epilepsy (SUDEP). An animal model that employs kainic acid-induced seizures on a background of urethane anesthesia has permitted unprecedented access to the behavior of autonomic, cardiovascular, and respiratory systems during seizure activity. The result is a detailed description of the major causes of death and how this animal model can be used to develop and test preventative and interventional strategies. A critical translational step was taken when the rat data were shown to directly parallel data from definite SUDEP cases in the clinical literature. The reasons why ventricular fibrillation as a cause of death is so rarely reported and tools for verifying that seizure-associated laryngospasm can induce obstructive apnea as a cause of death are discussed in detail. Many details of the specific kinetics of activation of brainstem neurons serving autonomic and respiratory function remain to be elucidated, but the boundary conditions described in this review provide an excellent framework for more focused studies. A number of studies conducted in animal models of seizure activity and in epilepsy patients have contributed information on the autonomic, cardiovascular, and respiratory consequences of seizure activity spreading through hypothalamus and brainstem to the periphery. The result is detailed information on the systemic impact of seizure spread and the development of an understanding of the essential mechanistic features of sudden unexpected death in epilepsy (SUDEP). This review summarizes translation of data obtained from animal models to biomarkers that are useful in evaluating data from epilepsy patients.

Ictal bradyarrhythmias and asystole requiring pacemaker implantation: Combined EEG-ECG analysis of 5 cases

BACKGROUND

Seizures can lead to cardiac arrhythmias by a number of mechanisms including activation/inhibition of cortical autonomic centers, increase in vagal tone through activation of brainstem reflex centers, and respiratory failure. Ictal asystole (IA) is a potential mechanism underlying sudden unexpected death in epilepsy (SUDEP). We analyzed the clinical features of 5 patients who developed IA requiring pacemaker implantation.

METHODS

Patients with ictal arrhythmias were identified from the video-telemetry and ambulatory EEG database at Greater Manchester Neurosciences Centre, as well as an independent epilepsy residential care facility. Only those who had IA requiring pacemaker implantation were included in the analysis. A total of 5 patients were identified.

RESULTS

Of the 5 patients with IA, 4 were female. All 5 patients had focal epilepsy, and four had temporal lobe epilepsy. Ictal asystole occurred with focal seizures with impairment of awareness. Seizure onset was left-sided in 2 patients, right-sided in one, left-sided onset with switch of lateralization in one, and nonlateralized in one patient. Three patients had hippocampal sclerosis, one of whom had undergone epilepsy surgery, one had traumatic encephalomalacia of the temporal lobe, and one patient had no lesions detected on MRI. Interictal epileptiform activity was more pronounced during sleep in all patients. Asystole occurred in association with sleep-related seizures in 4 of 5 patients.

CONCLUSIONS

Ictal asystole (IA) occurred in association with sleep-related seizures in 4 out of 5 cases, predominantly in patients with temporal lobe epilepsy. These findings may be of relevance to SUDEP.

The heart of epilepsy: Current views and future concepts

Cardiovascular (CV) comorbidities are common in people with epilepsy. Several mechanisms explain why these conditions tend to co-exist including causal associations, shared risk factors and those resulting from epilepsy or its treatment. Various arrhythmias occurring during and after seizures have been described. Ictal asystole is the most common cause. The converse phenomenon, arrhythmias causing seizures, appears extremely rare and has only been reported in children following cardioinihibitory syncope. Arrhythmias in epilepsy may not only result from seizure activity but also from a shared genetic susceptibility. Various cardiac and epilepsy genes could be implicated but firm evidence is still lacking. Several antiepileptic drugs (AEDs) triggering conduction abnormalities can also explain the co-existence of arrhythmias in epilepsy. Epidemiological studies have consistently shown that people with epilepsy have a higher prevalence of structural cardiac disease and a poorer CV risk profile than those without epilepsy. Shared CV risk factors, genetics and etiological factors can account for a significant part of the relationship between epilepsy and structural cardiac disease. Seizure activity may cause transient myocardial ischaemia and the Takotsubo syndrome. Additionally, certain AEDs may themselves negatively affect CV risk profile in epilepsy. Here we discuss the fascinating borderland of epilepsy and cardiovascular conditions. The review focuses on epidemiology, clinical presentations and possible mechanisms for shared pathophysiology. It concludes with a discussion of future developments and a call for validated screening instruments and guidelines aiding the early identification and treatment of CV comorbidity in epilepsy.

Functional State of the Heart during Spontaneous Nonconvulsive Seizure Activity at Various Times of the Day

Circadian peculiarities of HR regulation and functional capacities of the heart in WAG/Rij rats with genetically determined absence epilepsy are related to spike-wave activity of the brain. The number of spike-wave discharges (SWD) is maximum at night, early morning, and evening time and decreases to minimum at 08.00-16.00. At night, functional capacities of the heart are reduced and stress test at night induces ischemic changes in the myocardium at a lower functional load than in the daytime (low level of SWD activity). The decrease in the number of SWD and spike-wave index during the daytime contributes to the central mechanisms of autonomic regulation of the heart. However, these capacities are reduced against the background of increased seizure activity during nighttime.

Impact of periictal nurse interventions on postictal generalized EEG suppression in generalized convulsive seizures

OBJECTIVES

The objective of this study was to determine the impact of periictal nurse interventions on postictal generalized EEG suppression (PGES) in generalized convulsive seizures (GCS).

METHODS

We retrospectively reviewed the video-EEG recordings of patients during long-term video-EEG monitoring. We compared the duration of seizures, seizure phases (tonic, clonic, and tonic-clonic phases), and the occurrence and duration of postictal generalized EEG suppression (PGES) in patients with and without periictal interventions (e.g., oxygen administration, suctioning, and repositioning). Statistical analyses were performed to determine the association between the seizure-related variables and the periictal interventions.

RESULTS

A total of 109 patients with 150 GCS were included in the study. Periictal interventions were provided in 122 GCS, of which, ictal administration of oxygen was provided in 29 GCS. The duration of PGES was significantly shortened in GCS with interventions when compared with those without interventions (p=0.003). However, the ictal administration of oxygen, assessed as an independent variable, did not influence the occurrence or duration of PGES.

CONCLUSION

Periictal interventions significantly shortened the duration of PGES, and may, as a consequence, reduce the risk of SUDEP. However, ictal administration of oxygen did not influence the occurrence or duration of PGES.

Cardiac and autonomic mechanisms contributing to SUDEP

Sudden unexpected death in epilepsy is likely caused by a cascade of events affecting the vegetative nervous system leading to cardiorespiratory failure and death. Multiple genetic, electrophysiological, neurochemical, and pharmacological cardiac alterations have been associated with epilepsy, which can affect autonomic regulation of the heart and predispose patients to sudden unexpected death in epilepsy. These cardiac and autonomic changes are more frequently seen in patients with longstanding and medication refractory epilepsy and may be a prerequisite for sudden unexpected death in epilepsy. Cardiac changes are also observed within the immediate periictal period in patients with and without preexisting cardiac pathology and could be the tipping point in the cascade of events compromising autonomic, respiratory, and cardiac function during an epileptic convulsion. Better understanding if and how these cardiac alterations can make a particular individual with epilepsy more susceptible to sudden unexpected death in epilepsy will hopefully lead us to more effective preventative strategies.

Sudden infant death syndrome, sleep, and seizures

benign febrile seizures seen in 7% of infants before 6 months play a role in the terminal pathway in a subset of sudden infant death syndrome victims. Supporting evidence: (1) lack of 5-hydroxitryptamine, one consistent finding in sudden infant death syndrome that Kinney et al coined a developmental serotonopathy, is consistent with risk for seizures. (2) Non-rapid eye movement sleep increasing during the age of highest risk for sudden infant death syndrome facilitates some seizures (seizure gate). (3) Sudden unexpected death in epilepsy is associated with severe hypoxemia and hypercapnia during postictal generalized electroencephalographic (EEG) suppression. In toddlers, sudden unexplained deaths are associated with hippocampal abnormalities and some seizures. (4) The sudden nature of both deaths warrants an exploration of similarities in the terminal pathway. Moreover, sudden infant death syndrome, febrile seizures, sudden unexplained death in childhood, and sudden unexpected death in epilepsy share some of the following risk factors: prone sleeping, infections, hyperthermia, preterm birth, male gender, maternal smoking, and mutations in genes that regulate sodium channels. State-of-the-art molecular studies can be exploited to test this hypothesis.

Serotonin neurones have anti-convulsant effects and reduce seizure-induced mortality

Sudden unexpected death in epilepsy (SUDEP) is the leading cause of death in patients with refractory epilepsy. Defects in central control of breathing are important contributors to the pathophysiology of SUDEP, and serotonin (5-HT) system dysfunction may be involved. Here we examined the effect of 5-HT neurone elimination or 5-HT reduction on seizure risk and seizure-induced mortality. Adult Lmx1b(f/f/p) mice, which lack >99% of 5-HT neurones in the CNS, and littermate controls (Lmx1b(f/f)) were subjected to acute seizure induction by maximal electroshock (MES) or pilocarpine, variably including electroencephalography, electrocardiography, plethysmography, mechanical ventilation or pharmacological therapy. Lmx1b(f/f/p) mice had a lower seizure threshold and increased seizure-induced mortality. Breathing ceased during most seizures without recovery, whereas cardiac activity persisted for up to 9 min before terminal arrest. The mortality rate of mice of both genotypes was reduced by mechanical ventilation during the seizure or 5-HT2A receptor agonist pretreatment. The selective serotonin reuptake inhibitor citalopram reduced mortality of Lmx1b(f/f) but not of Lmx1b(f/f/p) mice. In C57BL/6N mice, reduction of 5-HT synthesis with para-chlorophenylalanine increased MES-induced seizure severity but not mortality. We conclude that 5-HT neurones raise seizure threshold and decrease seizure-related mortality. Death ensued from respiratory failure, followed by terminal asystole. Given that SUDEP often occurs in association with generalised seizures, some mechanisms causing death in our model might be shared with those leading to SUDEP. This model may help determine the relationship between seizures, 5-HT system dysfunction, breathing and death, which may lead to novel ways to prevent SUDEP.

Relation of autonomic and cardiac abnormalities to ventricular fibrillation in a rat model of epilepsy

Cardiac autonomic, conduction, and structural changes may occur in epilepsy and may contribute to sudden unexpected death in epilepsy (SUDEP), e.g. by increasing the risk for ventricular fibrillation (VF). In a model of chronic seizures in rats, we sought to study (1) cardiac and autonomic derangements that accompany the epileptic state, (2) whether chronically seizing rats experienced more significant cardiac effects after severe acute seizures, and (3) the susceptibility of chronically seizing rats to VF arising from autonomic and hypoxemic changes, which commonly occur during seizures. Sprague-Dawely rats were injected with saline or kainic acid to induce chronic seizures. At 2-3 months or 7-11 months after injection, these rats were studied with both 12-lead electrocardiography (to assess heart rate variability and QT dispersion) and echocardiography under ketamine/xylazine or urethane anesthesia. Hearts were subsequently excised, weighed, and examined histologically. Epileptic rats exhibited decreased vagal tone, increased QT dispersion, and eccentric cardiac hypertrophy without significant cardiac fibrosis, especially at 7-11 months post-injection. Of these three findings, vagal tone was inversely correlated with heart weights. Epileptic rats exhibited diminished systolic function compared to controls after severe acute seizures. However, animals with long-standing chronic seizures were less susceptible to autonomic/hypoxemia-driven VF, and their susceptibility inversely correlated with mean left ventricular wall thickness on histology. On the basis of this model, we conclude that cardiac changes accompany epilepsy and these can lead to significant seizure-associated cardiac performance decreases, but these cardiac changes actually lower the probability of VF.

Periictal autonomic dysfunction and generalized postictal EEG suppression in convulsive seizures arising from sleep and wakefulness

Sleep appears to be an independent risk factor of sudden unexpected death in epilepsy (SUDEP). We retrospectively determined the periictal electrophysiological characteristics of nocturnal and diurnal generalized convulsive seizures (GCSs) in 109 patients. Our data showed that preictal heart rate (HR) was significantly lower in 46 patients with nocturnal GCSs than in 63 patients with diurnal GCSs (p=0.002). However, there was no significant difference in postictal HR and respiratory rate (RR), total seizure duration, total convulsive phase, tonic phase, and clonic phase. Meanwhile, postictal generalized EEG suppression (PGES) was observed in 52.4% of the patients with diurnal GCSs and 67.4% of the patients with nocturnal GCSs. Duration of PGES was 38.2±17.3s in patients with diurnal GCSs and 49.5±21.7s in patients with nocturnal GCSs. There was also no significant difference in the prevalence (p=0.118) and duration (p=0.044, Bonferroni-corrected significant level: α=0.00625) of PGES in the two patient groups. Therefore, there is no clear evidence to attribute the SUDEP risk associated with sleep to postictal autonomic dysfunction and PGES, as compared to wakefulness.

Involvement of cardiomyocyte apoptosis in myocardial injury of hereditary epileptic rats

Many clinical cases have been reported where epilepsy profoundly influenced the pathophysiological function of the heart; however, the underlying mechanisms were not elucidated. We use the tremor (TRM) rat as an animal model of epilepsy to investigate the potential mechanisms of myocardial injury. Cardiac functions were assessed by arrhythmia score, heart rate, heart:body mass ratio, and hemodynamic parameters including left ventricular systolic pressure (LVSP), left ventricular end-diastolic pressure (LVEDP), and maximum rate of left ventricular pressure rise and fall (+dp/dtmax and -dp/dtmax). Catecholamine level was detected by HPLC. Apoptotic index was estimated by TUNEL assay. The expressions of Bcl-2, Bax, caspase-3, extracellular signal-regulated protein kinase (ERK), c-Jun NH2-terminal protein kinases (JNK), and p38 were evaluated by Western blot. The results indicated that there existed cardiac dysfunction and cardiomyocyte apoptosis, accompanied by increasing catecholamine levels in TRM rats. Further investigation revealed that apoptosis was mediated by reducing Bcl-2, upregulating Bax, and activating caspase-3. Additional experiments demonstrated that P-ERK1/2 was decreased, whereas P-JNK and P-p38 were up-regulated. Our results suggest that the sympathetic nervous system activation and cardiomyocyte apoptosis are involved in the myocardial injury of TRM rats. The mechanisms of apoptosis might be associated with the activation of the mitochondria-initiated and the mitogen-activated protein kinase pathways.

Dynamic J-Point Elevation Associated with Epileptic Hemiplegia: The Osborn Wave of Todd's Paralysis

THIS CASE REPORT EXPOSES A PHENOMENON WHICH, ALTHOUGH PROPOSED, HAS NOT BEEN DESCRIBED IN CLINICAL LITERATURE: transient postictal hemiplegia (Todd's paralysis) with concomitant electrocardiographic J-point deflection (Osborn waves). Although typically associated with hypothermia, a prominent J-wave on the electrocardiogram (ECG) results from a transmyocardial voltage gradient during ventricular repolarization. Rarely, the Osborn wave may be observed in a non-hypothermic setting such as hypercalcemia or cerebral hemorrhage. Transient postictal hemiplegia has been attributed to localized cerebral hypoperfusion resulting from motor cortex exhaustion following an epileptic seizure. The same central nervous system autonomic dysfunction has been theorized to produce subendocardial hypoperfusion with electrocardiographic change and cardiac troponin T elevation. This is the first described ECG evidence of a dynamically displaced J-point in the setting of postictal hemiplegia.

Sudden unexpected death in epilepsy in children

Sudden unexpected death in epilepsy (SUPEP) is the commonest cause of seizure-related mortality in people with intractable epilepsy. The incidence of SUDEP varies in different epilepsy populations, with lower rates in population-based studies, higher in referral populations and clinical trials of adjunct drugs for complex partial epilepsy, and highest rates for surgical series. Certain risk factors for SUDEP have been identified, with seizure activity being one of the strongest risk factor for SUDEP. Suspected underlying mechanisms include cardiac dysrhythmias, seizure-related apnoea and postictal respiratory arrest. Prevention of SUDEP has centred on seizure control, and SUDEP incidence has been reduced by epilepsy surgery in some studies. In this review, we present epidemiological data, and discuss risk factors and underlying pathophysiological mechanisms that are associated with SUDEP in children.

Management and long-term outcome in patients presenting with ictal asystole or bradycardia

PURPOSE

Ictal asystole (IA) and ictal bradycardia (IB) are rare autonomic symptoms during epileptic seizures and may be potentially life-threatening. Guidelines for the care of these patients are missing. The aim of this multicenter study was to evaluate the management and long-term outcome in patients with IA and IB.

PATIENTS AND METHODS

All patients with IA and IB were included from four epilepsy centers (Bielefeld, Kork, Marburg, and Zürich) from 2002 until 2009. Using a standardized assessment form, clinical data, treatment decisions, and outcomes were extracted from patient charts and simultaneous electroencephalography/electrocardiography (EEG/ECG) recordings.

KEY FINDINGS

Seizures with IA or IB were identified in 16 patients. In all patients an associated temporal seizure pattern was recorded and in 15 patients, sudden falls, fainting, or trauma was previously reported or recorded during the monitoring. In three patients (18.8%) diagnosis of focal epilepsy was newly established and anticonvulsive treatment was initiated. Two patients with refractory epilepsy underwent epilepsy surgery. In seven patients (43.8%) a cardiac pacemaker was implanted. In 14 of 16 treated patients, seizure freedom (n = 5) or absence of sudden falls, fainting, or trauma (n = 9) could be achieved. Two patients denied epilepsy surgery as well as a pacemaker and continue to have frequent falls and trauma.

SIGNIFICANCE

Our study demonstrates that epilepsy surgery and antiepileptic drugs may lead to sustained freedom of seizures as well as ictal syncope. In drug-resistant patients not suitable for epilepsy surgery, implantation of a cardiac pacemaker may prevent sudden falls as well as trauma. Based on our results and previously reported cases we propose a treatment algorithm.