Sino-atrial arrest due to temporal lobe epilepsy

A case report of sinoatrial arrest caused by temporal lobe epilepsy in subclinical glioblastoma

Background

Atrial fibrillation with symptomatic bradycardia, higher grade atrioventricular block, and sinus node disease are all common indications for permanent pacemaker implantation. The most frequent causes of sinus node disease treated with pacemaker implantation involve degenerative structural changes of the sinus node; less often, extrinsic causes (such as damage due to myocardial infarction or heightened parasympathetic nervous system activity) lead to pacemaker implantation.

Case presentation

A 50-year-old patient with syncope and documented sinoatrial arrest was referred. Neurologic exams (including CT and EEG) revealed no pathologies, so a pacemaker was implanted. Postoperatively, syncope occurred again due to a focal seizure during which sinus rhythm transitioned to atrial pacing by the device. Further neurologic testing revealed focal epilepsy. Six months later, stage IV glioblastoma was diagnosed and the patient was treated surgically.

Conclusion

Intracerebral tumors should be considered in the differential diagnosis for patients with unexplained sinoatrial block, as well as in patients with repeat syncope after pacemaker implantation. Cranial MRI could aid the diagnostic workup of such cases.

Arrhythmogenic seizures

Arrhythmogenic seizures may represent one of the mechanisms implicated in sudden unexpected death in epilepsy. Various cardiac changes can be observed during epileptic seizures. However, reports of well-documented, life-threatening cardiac arrhythmias in the literature are scarce. The pathogenesis of these arrhythmias and speculations about the cortical localization of cardioarrhythmogenic triggers are reviewed.

Does epilepsy surgery lower the mortality of drug-resistant epilepsy?

Drug-resistant epilepsy has proved to be associated with an increased standardized mortality ratio (SMR), primarily due to seizure-related fatalities including sudden unexpected death (SUDEP). Recent studies have suggested that the surgical cure of temporal lobe epilepsy (TLE) was likely to normalize the SMR of patients suffering from refractory TLE. However, these studies raise a number of methodological issues, which have not always been fully addressed. Some conclusions have relied on previously reported data, indicating a SMR of approximately 5, and a SUDEP incidence of 9/1000 patient-years in drug-resistant epilepsy. In fact, as shown in this review, SMR varied considerably, from 2 to 16, in the various series of patients with refractory epilepsy, whereas the average SUDEP incidence in the same populations was calculated at 3.7/1000 patient-years. Other conclusions were based on the comparison of either surgically and medically treated patients, or cured and non-cured operated patients. In both situations, the two groups included a different proportion of excellent and poor surgical candidates. The biological differences that distinguish these two populations might explain part of the differences observed in their mortality rate, regardless of the effect of surgery. In particular, temporal-plus epilepsies involving the insula, the frontal orbital, or the frontal operculum region, might favour ictal arrhythmias, central apnoea and secondary generalization, which in turn would increase the risk of SUDEP. Future studies are thus warranted to specifically address these issues.

Heart rate changes during partial seizures: a study amongst Singaporean patients

INTRODUCTION

Studies in Europe and America showed that tachycardia, less often bradycardia, frequently accompanied partial seizures in Caucasian patients. We determine frequency, magnitude and type of ictal heart rate changes during partial seizures in non-Caucasian patients in Singapore.

METHODS

Partial seizures recorded during routine EEGs performed in a tertiary hospital between 1995 and 1999 were retrospectively reviewed. All routine EEGs had simultaneous ECG recording. Heart rate before and during seizures was determined and correlated with epileptogenic focus. Differences in heart rate before and during seizures were grouped into 4 types: (1) >10% decrease; (2) -10 to +20% change; (3) 20-50% increase; (3) >50% increase.

RESULTS

Of the total of 37 partial seizures, 18 were left hemisphere (LH), 13 were right hemisphere (RH) and 6 were bilateral (BL) in onset. 51% of all seizures showed no significant change in heart rate (type 2), 22% had moderate sinus tachycardia (type 3), 11% showed severe sinus tachycardia (type 4), while 16% had sinus bradycardia (type 1). Asystole was recorded in one seizure. Apart from having more tachycardia in bilateral onset seizures, there was no correlation between side of ictal discharge and heart rate response. Compared to Caucasian patients, sinus tachycardia was considerably less frequent. Frequency of bradycardia was similar to those recorded in the literature.

CONCLUSIONS

Significant heart rate changes during partial seizures were seen in half of Singaporean patients. Although sinus tachycardia was the most common heart rate change, the frequency was considerably lower compared to Caucasian patients. This might be due to methodological and ethnic differences. Rates of bradycardia are similar to those recorded in the literature.

An infant with seizure-related bradycardia and asystole

We describe an infant girl with ictal bradycardia and asystole who died during an episode of seizure, despite anti-epileptic therapy and permanent cardiac pacemaker implantation. The mechanism of ictal bradycardia and the need to recognize it are therefore discussed. Timely cardiac intervention and adequate anticonvulsant therapy are essential for successful management.

Apnoea and bradycardia during epileptic seizures: relation to sudden death in epilepsy

OBJECTIVE

To record non-invasively ictal cardiorespiratory variables.

METHODS

Techniques employed in polysomnography were used in patients with epilepsy undergoing EEG-video recording at a telemetry unit.

RESULTS

Apnoea (> 10, range > 10-63, mean 24 s) was seen in 20 of 47 clinical seizures (three secondary generalised, 16 complex partial, and one tonic) and 10 of 17 patients. Apnoea was central in 10 patients, but obstructive apnoea was also recorded in three of 10. Oxyhaemoglobin saturation (SpO2) dropped to less than 85% in 10 seizures (six patients). An increase in heart rate was common (91% of seizures). Bradycardia/sinus arrest was documented in four patients (mean maximum RR interval 5.36, range 2.8-8.6 s) but always in the context of a change in respiratory pattern.

CONCLUSION

Ictal apnoea was often seen. The occurrence of bradycardia in association with apnoea suggests the involvement of cardiorespiratory reflexes. Similar mechanisms may operate in cases of sudden death in epilepsy.

Sudden death in epilepsy: a study of incidence in a young cohort with epilepsy and learning difficulty

Sudden death, often seizure related, may occur in patients with epilepsy. Population-based incidence is probably on the order of 1:1,000/year. The incidence is much higher in selected groups, however. We wished to establish the incidence of sudden unexpected death (SUD) in a young cohort with severe epilepsy and learning difficulties. The study cohort included 310 pupils with epilepsy enrolled at a special residential school between April 1970 and April 1993. The follow-up period totaling 4,135 person-years included a period of residence at the school as well as time after leaving. Age and sex standardized overall mortality ratio was 15.9 [95% confidence interval (CI) 10.6-23.0], with 20 of 28 deaths considered epilepsy related. An incidence of sudden death cases of 1:295/year was noted. All 14 sudden deaths occurred when the pupils were not under the close supervision of the school and most were unwitnessed, which has implications for prevention.