[Mistaking a long QT syndrome for epilepsy: does every seizure call for an ECG?]

A case of near-sudden unexpected death in epilepsy due to ventricular fibrillation

Sudden unexpected death in epilepsy (SUDEP) refers to the sudden and unexpected death of an epileptic patient with no other health issues, during normal activity, and for whom no other particular cause of death can be found. The exact cause of SUDEP has not been established yet; however, it is assumed to be caused by multiple organ failure involving the respiratory and cardiovascular systems. Some of the known risk factors are generalized tonic-clonic seizure, frequent epileptic seizure, early onset of epilepsy, long duration of seizure, nocturnal seizure, and combined therapy with antiepileptics. A number of seizure-related cardiac arrhythmia cases have been reported. Arrhythmias are mostly benign tachycardia or bradycardia, and ventricular fibrillation (VF) or asystole is very rare. It is considered that fatal cardiac arrhythmia is a cause of SUDEP. Here, we describe the case of a near-SUDEP patient who was successfully revived without complications by immediate defibrillation with an automated external defibrillator and cardiopulmonary resuscitation, although VF occurred after a convulsive seizure. Based on our experience, when treating a patient with an epileptic seizure, one should always keep in mind the possibility of SUDEP as a seizure-induced emergency situation involving fatal arrhythmia and cardiac arrest, even in young healthy adults.

A predictive index of biomarkers for ictogenesis from tier I safety pharmacology testing that may warrant tier II EEG studies

Three significant contributions to the field of safety pharmacology were recently published detailing the use of electroencephalography (EEG) by telemetry in a critical role in the successful evaluation of a compound during drug development (1] Authier, Delatte, Kallman, Stevens & Markgraf; JPTM 2016; 81:274-285; 2] Accardi, Pugsley, Forster, Troncy, Huang & Authier; JPTM; 81: 47-59; 3] Bassett, Troncy, Pouliot, Paquette, Ascaha, & Authier; JPTM 2016; 70: 230-240). These authors present a convincing case for monitoring neocortical biopotential waveforms (EEG, ECoG, etc) during preclinical toxicology studies as an opportunity for early identification of a central nervous system (CNS) risk during Investigational New Drug (IND) Enabling Studies. This review is about "ictogenesis" not "epileptogenesis". It is intended to characterize overt behavioral and physiological changes suggestive of drug-induced neurotoxicity/ictogenesis in experimental animals during Tier 1 safety pharmacology testing, prior to first dose administration in man. It is the presence of these predictive or comorbid biomarkers expressed during the requisite conduct of daily clinical or cage side observations, and in early ICH S7A Tier I CNS, pulmonary and cardiovascular safety study designs that should initiate an early conversation regarding Tier II inclusion of EEG monitoring. We conclude that there is no single definitive clinical marker for seizure liability but plasma exposures might add to set proper safety margins when clinical convulsions are observed. Even the observation of a study-related full tonic-clonic convulsion does not establish solid ground to require the financial and temporal investment of a full EEG study under the current regulatory standards.

PREFATORY NOTE

For purposes of this review, we have adopted the FDA term "sponsor" as it refers to any person who takes the responsibility for and initiates a nonclinical investigations of new molecular entities; FDA uses the term "sponsor" primarily in relation to investigational new drug application submissions.

Interictal cardiac repolarization abnormalities in people with epilepsy

BACKGROUND AND OBJECTIVE

The occurrence of cardiac electrical abnormalities such as repolarization disorders in patients with epilepsy was previously documented and may, in part, clarify the mechanism of sudden unexpected death in those patients. The aim of this study was to investigate the frequency of cardiac repolarization disorders among patients with epilepsy and whether specific demographic- or disease-related features were associated with their occurrence.

SUBJECTS AND METHODS

This cross-sectional study was carried out on 1000 subjects with epilepsy who were compared with age- and sex-matched 2500 subjects without epilepsy. Clinical assessment, which included careful history taking and examination, was carried out for all participants in addition to resting 12-lead electrocardiogram (ECG) recording. Electrocardiograms were reviewed by experienced cardiologists. Electrocardiogram intervals were measured, and morphological abnormalities were identified using standard guidelines.

RESULTS

Repolarization abnormalities were found in 142 (14.2%) patients with epilepsy. A statistically significant elevation in percentage of corrected QT interval (QTc) prolongation (both severe and borderline) among patients with epilepsy compared with controls was documented (8.4% vs 2%, P<0.001). Epilepsy increased the likelihood of hosting prolonged QTc more than 4 times (95% confidence interval: 3.175-6.515; odds ratio: 4.548; P<0.001). Affected patients were significantly older (95% confidence interval: 1.012-1.044; odds ratio: 1.027; P=0.001), and the abnormality was significantly more prevalent among those with poor seizure control (95% confidence interval: 1.103-2.966; odds ratio: 1.809; P=0.019). On the other hand, early repolarization (ER) pattern and Brugada type ECG pattern (BP) were significantly more prevalent in subjects without epilepsy.

CONCLUSIONS

Corrected QT interval prolongation (both severe and borderline) was more prevalent among patients with epilepsy, especially if uncontrolled or elderly. Electrocardiogram should be established as a part of the diagnostic workup of epilepsy in order to identify such electrocardiographic abnormality.

Relevance of long QT syndrome in clinical neurology

Long QT syndrome (LQTS) is a cardiac conduction disorder that predisposes patients at potentially fatal cardiac events. Inherited conditions and acquired factors contribute to LQTS. A number of frequently prescribed CNS-active drugs prolong the QT interval. The clinical neurologist may encounter LQTS when initiating a pharmacotherapy or when increasing the dosage of drugs. The clinical neurologist may also encounter LQTS during the diagnostic work-up of patients with unexplained loss of consciousness, because LQTS may present as convulsive syncope. Some studies report an association of LQTS and stroke. Awareness of LQTS may help to recognize and prevent potentially fatal cardiac events associated with LQTS. This concise article highlights the clinically most relevant aspects of LQTS in the field of neurology.