Children with refractory epilepsy demonstrate alterations in myocardial strain

Associations between epilepsy, respiratory impairment, and minor ECG abnormalities in children

OBJECTIVE

We sought to examine the effects of acute seizures and respiratory derangement on the cardiac electrical properties reflected on the electrocardiogram (ECG); and to analyze their potential interactions with a diagnosis of epilepsy in children.

METHODS

Emergency center (EC) visits with seizure or epilepsy diagnostic codes from 1/2011-12/2013 were included if they had ECG within 24 h of EC visit. Patients were excluded if they had pre-existing cardiac conditions, ion channelopathy, or were taking specific cardiac medications. Control subjects were 1:1 age and gender matched. Abnormal ECG was defined as changes in rhythm, PR, QRS, or corrected QT intervals; QRS axis or morphology; ST segment; or T wave morphology from normal standards. We identified independent associations between clinical factors and abnormal ECG findings using multivariable logistic regression modeling.

RESULTS

Ninety-five children with epilepsy presented to the EC with seizures, respiratory distress, and other concerns. Three hundred children without epilepsy presented with seizures. There was an increased prevalence of minor ECG abnormalities in children with epilepsy (49 %) compared to the control subjects (29 %) and those without epilepsy (36 %). Epilepsy (OR: 1.61, 95 %CI: 1.01-2.6), need for supplemental oxygen (OR 3.06, 95 % CI: 1.45-6.44) or mechanical ventilation (OR: 2.5, 95 % CI: 1.03-6.05) were independently associated with minor ECG abnormalities. Secondary analyses further demonstrated an independent association between level of respiratory support and ECG abnormalities only in the epilepsy group.

SIGNIFICANCE

Independent association of increased respiratory support with minor ECG abnormalities suggests a potential respiratory influence on the hearts of children with epilepsy.

Sudden death in epilepsy: the overlap between cardiac and neurological factors

People with epilepsy are at risk of premature death, of which sudden unexpected death in epilepsy (SUDEP), sudden cardiac death (SCD) and sudden arrhythmic death syndrome (SADS) are the primary, partly overlapping, clinical scenarios. We discuss the epidemiologies, risk factors and pathophysiological mechanisms for these sudden death events. We reviewed the existing evidence on sudden death in epilepsy. Classification of sudden death depends on the presence of autopsy and expertise of the clinician determining aetiology. The definitions of SUDEP, SCD and SADS lead to substantial openings for overlap. Seizure-induced arrhythmias constitute a minority of SUDEP cases. Comorbid cardiovascular conditions are the primary determinants of increased SCD risk in chronic epilepsy. Genetic mutations overlap between the states, yet whether these are causative, associated or incidentally present is often unclear. Risk stratification for sudden death in people with epilepsy requires a multidisciplinary approach, including a review of clinical history, toxicological analysis and complete autopsy with histologic and, preferably, genetic examination. We recommend pursuing genetic testing of relatives of people with epilepsy who died suddenly, mainly if a post-mortem genetic test contained a Class IV/V (pathogenic/likely pathogenic) gene variant. Further research may allow more precise differentiation of SUDEP, SCD and SADS and the development of algorithms for risk stratification and preventative strategies.

Association of minor electrocardiographic (ECG) abnormalities with epilepsy duration in children: A manifestation of the epileptic heart?

PURPOSE

Cardiac abnormalities resulting from chronic epilepsy ("the epileptic heart") constitute a well-recognized comorbidity. However, the association of cardiac alterations with epilepsy duration remains understudied. We sought to evaluate this association using electrocardiogram (ECG).

METHODS

We prospectively enrolled children between 1 months and 18 years of age without known cardiac conditions or ion channelopathies during routine clinic visits. ECGs were categorized as abnormal if there were alterations in rhythm; PR, QRS, or corrected QT interval; QRS axis or morphology; ST segment or T wave. An independent association between ECG abnormalities and epilepsy duration was evaluated using multivariable logistic regression modeling.

RESULTS

213 children were enrolled. 100 ECGs (47%) exhibited at least one alteration; most commonly in the ST segment (37, 17%) and T wave (29, 11%). Children with normal ECGs had shorter epilepsy duration as compared to those with ECG abnormalities (46 [18-91] months vs. 73 [32-128 months], p = 0.004). A multivariable logistic regression model demonstrated that increasing epilepsy duration was independently associated with the presence of ECG abnormalities (OR=1.09, 95% CI=1.02-1.16, p = 0.008), adjusted for seizure frequency, generalized tonic-clonic/focal to bilateral tonic-clonic seizures as the predominant seizure type, and number of channel-modifying anti-seizure medications. Increasing epilepsy duration was also independently associated with the presence of ST/T wave abnormalities (OR=1.09, 95% CI=1.01-1.16, p = 0.017), adjusted for the same covariates.

SIGNIFICANCE

Increasing epilepsy duration is independently associated with the presence of minor ECG abnormalities. Additional studies are needed to evaluate whether this finding may represent a manifestation of the "epileptic heart".

The epileptic heart: Cardiac comorbidities and complications of epilepsy. Atrial and ventricular structure and function by echocardiography in individuals with epilepsy - From clinical implications to individualized assessment

Epilepsy is an increasing global neurological health issue. Recently, epidemiological and mechanistic studies have raised concern about cardiac involvement in individuals with epilepsy. This has resulted in the "epileptic heart" concept. Epidemiological data linking epilepsy to cardiovascular disease indicate an increased risk for ventricular and atrial arrhythmias, myocardial infarction, heart failure, and sudden death among individuals with epilepsy. Pathways of this interaction comprise increased prevalence of traditional cardiac risk factors, genetic abnormalities, altered brain circuitry with autonomic imbalance, and antiseizure medications with enzyme-inducing and ionic channel-blocking proprieties. Pathophysiological findings in the atria and ventricles of patients with epilepsy are discussed. Echocardiographic findings and future applications of this tool are reviewed. A risk stratification model and future studies on cardiac risk assessment in individuals with epilepsy are proposed.

Cardiac dysfunctions in children with drug-resistant epilepsy

Objective

There were reports of cardiac dysfunction that led to sudden unexpected death in epilepsy (SUDEP) in patients with epilepsy. Early detection of cardiac dysfunction can lead to early management to prevent sudden cardiac death in these patients. The objective of our study is to assess cardiac functions in children with drug-resistant epilepsy (DRE) compared with the normal population by using a standard echocardiogram (SE), tissue Doppler imaging (TDI) and myocardial strain evaluations (MSE).

Method

Twenty-seven children who have been diagnosed with DRE based on the International League against Epilepsy (ILAE) were included in the study, along with 27 children whose ages match those of the normal control group.

Results

Seventeen children, median age 12 years old, were using more than four anti-seizure medications. Structural brain lesions were the most common cause of epilepsy, 55.6% (15). Generalized tonic-clonic seizures were the most common seizure type, 55.6% (15). Children with DRE had a lower early mitral valve E wave inflow velocity compared with the control group (p < 0.05). They also had lowered early diastolic velocities (e') and myocardial performance index (MPI) when compared with the control group (p < 0.05). There was a statistically significant difference in left ventricular myocardial strain in children with DRE, with an average of -21.1 (IQR -23.5 and -19.4) and control, -25.5 (IQR -27.3 and -24.2).

Significance

Children with DRE have an impairment of left ventricular diastolic function and myocardial strain, which could indicate decreased myocardial deformation and contraction compared with controls. These cardiological assessments can be used to evaluate children with DRE for early diagnosis and management of their cardiac dysfunction.

Autonomic manifestations of epilepsy: emerging pathways to sudden death?

Epileptic networks are intimately connected with the autonomic nervous system, as exemplified by a plethora of ictal (during a seizure) autonomic manifestations, including epigastric sensations, palpitations, goosebumps and syncope (fainting). Ictal autonomic changes might serve as diagnostic clues, provide targets for seizure detection and help us to understand the mechanisms that underlie sudden unexpected death in epilepsy (SUDEP). Autonomic alterations are generally more prominent in focal seizures originating from the temporal lobe, demonstrating the importance of limbic structures to the autonomic nervous system, and are particularly pronounced in focal-to-bilateral and generalized tonic-clonic seizures. The presence, type and severity of autonomic features are determined by the seizure onset zone, propagation pathways, lateralization and timing of the seizures, and the presence of interictal autonomic dysfunction. Evidence is mounting that not all autonomic manifestations are linked to SUDEP. In addition, experimental and clinical data emphasize the heterogeneity of SUDEP and its infrequent overlap with sudden cardiac death. Here, we review the spectrum and diagnostic value of the mostly benign and self-limiting autonomic manifestations of epilepsy. In particular, we focus on presentations that are likely to contribute to SUDEP and discuss how wearable devices might help to prevent SUDEP.

Left ventricular dysfunction and cardiac autonomic imbalance in children with drug-resistant epilepsy

BACKGROUND

Resistance to antiepileptic drug treatment increases the risk of comorbidities and mortality due to a cardio-autonomic imbalance and left ventricular (LV) dysfunction.

OBJECTIVE

To assess the prevalence of LV dysfunction and cardio-autonomic imbalance in children with drug-resistant epilepsy (DRE).

PATIENTS AND METHODS

This cross-sectional study included 40 children with DRE and 40 healthy age- and sex-matched controls. LV function was evaluated by M-mode, two-dimensional, pulse-wave Doppler echocardiography, and tissue Doppler imaging (TDI). Cardio-autonomic function was assessed by 24 -h Holter monitoring of heart rate variability.

RESULTS

All time domain measures were significantly lower in the epilepsy group than in the control group (all Ps<0.01). Additionally, the mean high frequency (HF) parameters were significantly lower (P = 0.035), whereas the mean low frequency (LF) parameters and the LF/HF ratio were significantly higher (P < 0.001) in the epilepsy group than in the control group. LV function did not differ between groups regarding all standard echocardiographic parameters. There was evidence of subclinical LVdysfunction by tissue doppler among the epileptic group, as evidenced by the elevated Myocardial Performance Index, isovolumetric relaxation time and mitral E/Em ratio. There was no significant correlation between the duration of epilepsy or seizure frequency with any cardiac abnormality.

CONCLUSIONS

Children with DRE exhibited cardio-autonomic and subclinical LV dysfunction, independent of the duration of epilepsy, frequency, and seizure type.

The brain-heart interaction in epilepsy: implications for diagnosis, therapy, and SUDEP prevention

The influence of the central nervous system and autonomic system on cardiac activity is being intensively studied, as it contributes to the high rate of cardiologic comorbidities observed in people with epilepsy. Indeed, neuroanatomic connections between the brain and the heart provide links that allow cardiac arrhythmias to occur in response to brain activation, have been shown to produce arrhythmia both experimentally and clinically. Moreover, seizures may induce a variety of transient cardiac effects, which include changes in heart rate, heart rate variability, arrhythmias, asystole, and other ECG abnormalities, and can trigger the development of Takotsubo syndrome. People with epilepsy are at a higher risk of death than the general population, and sudden unexpected death in epilepsy (SUDEP) is the most important direct epilepsy-related cause of death. Although the cause of SUDEP is still unknown, cardiac abnormalities during and between seizures could play a significant role in its pathogenesis, as highlighted by studies on animal models of SUDEP and registration of SUDEP events. Recently, genetic mutations in genes co-expressed in the heart and brain, which may result in epilepsy and cardiac comorbidity/increased risk for SUDEP, have been described. Recognition and a better understanding of brain-heart interactions, together with new advances in sequencing techniques, may provide new insights into future novel therapies and help in the prevention of cardiac dysfunction and sudden death in epileptic individuals.