The usefulness of the head-up tilt test in patients with suspected epilepsy

Association between Syncope and the 6-Month Incidence of Ischemic Stroke, Arrhythmia, Brain Tumor, Epilepsy, and Anxiety Disorder

OBJECTIVES

the aim of the present study is to investigate the associations between syncope and subsequent diagnoses of brain tumor, cardiac arrhythmia, stroke/transient ischemic attack (TIA), epilepsy, and anxiety disorder in a large outpatient population in Germany.

METHODS

This retrospective cohort study uses data from the Disease Analyzer database (IQVIA). Adults who received syncope diagnosis from one of 1284 general practices between January 2005 and December 2021 (index date) were included and matched (1:1) to individuals without syncope diagnosis using a propensity score based on age, sex, the number of consultations during the follow-up period (up to 6 months), and defined co-diagnoses documented within 12 months prior to and on the index date. Finally, associations between syncope and subsequent outcome diagnoses were investigated using multivariable logistic regression models.

RESULTS

Data related to 64,016 patients with and 64,016 patients without syncope (mean age 54.5 years, 56.5% female) were available. In total, 6.43% of syncope patients and 2.14% of non-syncope patients were diagnosed with one of the five outcome diagnoses within 6 months of the index date. There was a positive and significant association between syncope and incidences of ischemic stroke/TIA (OR = 2.83, 95% CI = 2.41-3.32), arrhythmia (OR = 3.81, 95% CI = 3.44-4.18), brain tumor (OR = 4.24, 95% CI = 2.50-7.19), epilepsy (OR = 5.52, 95% CI = 4.27-7.14), and anxiety disorder (OR = 1.99, 95% CI = 1.79-2.21).

CONCLUSIONS

Syncope is significantly associated with an increased risk of subsequent ischemic stroke/TIA, cardiac arrhythmia, brain tumor, epilepsy, and anxiety disorder. Nevertheless, the cumulative incidences for all five diagnoses are very low.

Tilt testing remains a valuable asset

Head-up tilt test (TT) has been used for >50 years to study heart rate/blood pressure adaptation to positional changes, to model responses to haemorrhage, to assess orthostatic hypotension, and to evaluate haemodynamic and neuroendocrine responses in congestive heart failure, autonomic dysfunction, and hypertension. During these studies, some subjects experienced syncope due to vasovagal reflex. As a result, tilt testing was incorporated into clinical assessment of syncope when the origin was unknown. Subsequently, clinical experience supports the diagnostic value of TT. This is highlighted in evidence-based professional practice guidelines, which provide advice for TT methodology and interpretation, while concurrently identifying its limitations. Thus, TT remains a valuable clinical asset, one that has added importantly to the appreciation of pathophysiology of syncope/collapse and, thereby, has improved care of syncopal patients.

Recurrent seizures in a young woman: when video-EEG diagnoses a cardiac cause: a case report

Background

While transient loss of consciousness is a frequent presenting symptom, differential diagnosis between syncope and epilepsy can be challenging. Misdiagnosis of epilepsy leads to important psychosocial consequences and eliminates the opportunity to treat patient’s true condition.

Case summary

A 39-year-old woman presenting with recurrent seizures since her childhood was referred to neurological consultation. Electroencephalograms (EEGs) and magnetic resonance imaging previously performed were normal. A sleep-deprived video-EEG was performed and highlighted after 12 h of sleep deprivation a progressive dropping of the heart rate followed by a complete heart block without ventricular escape rhythm and asystole for about 30 s. Her EEG recording later showed diffuse slow waves traducing a global cerebral dysfunction and suffering. The diagnosis of vaso-vagal syncope with predominant cardioinhibitory response was made and a dual-chamber pacemaker with rate-drop response algorithm was implanted. After a 2 years of follow-up, the patient remained free of syncope.

Discussion

Patients presenting with loss of consciousness and convulsion are often diagnosed with epilepsy despite normal EEGs. In patients presenting with recurrent seizures with unclear diagnosis of epilepsy or in a situation of drug-resistant epilepsy, syncope diagnosis should always be considered and a risk stratification is necessary. The benefit of pacemaker implantation in patients with recurrent vaso-vagal syncope is still very controversial. Only patients presenting with spontaneous asystole should be considered for pacemaker implantation in case of recurrent vaso-vagal syncope.

Syncope and Epilepsy coexist in 'possible' and 'drug-resistant' epilepsy (Overlap between Epilepsy and Syncope Study - OESYS)

Background

Differential diagnosis between syncope and epilepsy in patients with transient loss of consciousness of uncertain etiology is still unclear. Thus, the aim of the present work is to evaluate the prevalence of syncope in patients with “possible” or “drug-resistant” epilepsy.

Methods

The Overlap between Epilepsy and SYncope Study (OESYS) is a multicenter prospective observational study designed to estimate the prevalence of syncope in patients followed in Epilepsy Centers for “possible” or “drug-resistant” epilepsy and assessed according the European Society of Cardiology (ESC) guidelines of syncope diagnosis.

Results

One hundred seven patients were evaluated; 63 (58.9%) had possible and 44 (41.1%) drug-resistant epilepsy. A final diagnosis of isolated syncope was in 45 patients (42.1%), all with possible epilepsy (45/63, 71.4%). Isolated epilepsy was found in 21 patients (19.6%) and it was more frequent in the drug-resistant than in the possible epilepsy group (34.1% vs. 9.5%, p = 0.002). More importantly, syncope and epilepsy coexisted in 37.4% of all patients but the coexistence was more frequent among patients with drug-resistant than possible epilepsy (65.9% vs. 17.5%, p < 0.001).

Conclusions

Isolated syncope was diagnosed in ≈ 70% of patients with possible epilepsy. Syncope and epilepsy coexisted in ≈ 20% of patients with possible and in ≈ 60% of patients with drug-resistant epilepsy. These findings highlight the need of ESC guidelines of syncope approach in patients with possible and drug-resistant epilepsy.

Time- and frequency-domain analysis of beat to beat P-wave duration, PR interval and RR interval can predict asystole as form of syncope during head-up tilt

To seek possible differences in short-period temporal RR interval, P-wave and PR interval dispersion and spectral coherence in patients with a head-up tilt test positive for vasovagal syncope with or without prolonged asystole, severe symptoms and at high risk of trauma. We retrospectively reviewed 5 min ECG and blood pressure recordings obtained at baseline, at rest and during head-up tilt in 40 patients diagnosed as having recurrent vasovagal syncope confirmed at a head-up tilt test. We analysed autoregressive spectral power for all the ECG-derived variables, focusing on temporal P-wave and PR interval dispersion indexes as well as their spectral coherence calculated on the same 5 min recordings at rest and during tilt. ECG recordings obtained during tilt before syncope showed significantly lower P  →  PR spectral coherence and higher RR standard deviations in patients with tilt-induced asystole than in those without (0.567  ±  0.097 versus 0.670  ±  0.127, p: 0.010 and 84  ±  36 versus 46  ±  22 ms², p  <  0.0001). Differences in the RR standard deviations persisted also on the last hundred beats (_-100) (113  ±  54 versus 34  ±  17 ms², p  <  0.0001). Multiple regression analysis identified a significantly negative association between the maximum RR intervals and P  →  PR coherence at rest (β:  -0.3, p  <  0.05) and positive association with RR_-100 standard deviation during tilt-induced syncope (β: 0.621, p  <  0.001). P  →  PR spectral coherence could be used to assess the risk of prolonged asystole in patients with tilt-induced vasovagal syncope as well as as a possible surrogate for tilt-testing during these patients' follow-up.

Tilt table test today - state of the art

A tilt table test (TTT) is an inexpensive, noninvasive tool for the differential diagnosis of syncope and orthostatic intolerance and has good diagnostic yield. The autonomic system malfunction which underlines the reflex syncope is manifested as either hypotension or bradycardia, while an orthostatic challenge is applied. The timing of the response to the orthostatic challenge, as well as the predominant component of the response help to differentiate between various forms of neurocardiogenic syncope, orthostatic hypotension and non-cardiovascular conditions (e.g., pseudosyncope). Medications, such as isoproterenol and nitrates, may increase TTT sensitivity. Sublingual nitrates are easiest to administer without the need of venous access. TTT can be combined with carotid sinus massage to evaluate carotid sinus hypersensitivity, which may not be present in supine position. TTT is not useful to access the response to treatment. Recently, implantable loop recorders (ILR) have been used to document cardioinhibitory reflex syncope, because pacemakers are beneficial in many of these patients, especially those over 45 years of age. The stepwise use of both TTT and ILR is a promising approach in these patients. Recently, TTT has been used for indications other than syncope, such as assessment of autonomic function in Parkinson's disease and its differentiation from multiple system atrophy.

Usability of the head upright tilt test for differentiating between syncopal and seizure-like events in children

The common diagnosis of loss of consciousness and clonic movements in children is seizure or epilepsy, but in a number of patients these symptoms could also be due to syncope. Over interpreted electroencephalography is misleading in a number of patients; therefore, in addition to a detailed and thorough history, a reliable test is needed to differentiate between these conditions. The aim of the study was to evaluate the utility of the head upright tilt test to differentiate between seizure-like events and syncope in children. A chart review descriptive study was conducted in a tertiary medical center in Ahvaz, Iran. We selected sixteen children (nine boys and seven girls) with convulsions of any type who were first diagnosed as epileptic based on the event description by their parents or caregivers to undergo the head upright tilt test. The main findings were the reproduction of previously presyncopal or syncopal symptoms in the tilted position. Fourteen children showed positive results after conducting the head upright tilt test, and their heart rates were significantly decreased compared to baseline at the onset of the syncopal or presyncopal manifestations. Systolic and diastolic blood pressures were significantly reduced in patients with positive results. In three children who initially had negative head upright tilt tests, intravenous isoproterenol was administered, and all three showed presyncopal and syncopal symptoms. The results indicate that the head upright tilt test could differentiate presyncopal and syncopal events in children who present with seizure-like movements but their history has clues for conclusive syncope.

Plasma brain-type natriuretic Peptide level following seizure and syncope: pilot study

Background and Purpose:

To explore the clinical feasibility of plasma brain-type natriuretic peptide (proBNP) level to differentiate the two major causes of transient unconsciousness, seizure and vasovagal syncope (VVS) in adult patients.

Methods:

ProBNP levels were evaluated within 24 hours following attack in patients who had experienced a transient episode of unconsciousness. For confirmatory diagnosis, clinical history was reviewed thoroughly and several work-ups including electroencephalography and cerebral imaging and tilt-table test, were performed in cases of putative VVS, as a part of routine clinical approaches.

Results:

According to various relevant evaluations, 15 patients were diagnosed as seizure (age, 40.3±13.8 years) and 12 patients were VVS (age, 38.1±17.1 years). Plasma concentrations of pro-BNP were not different between two groups (p=0.714). Median level was 34.3 pg/mL (interquartile range: 12.9–91.1) in post-seizure group and 32.3 pg/mL (interquartile range 8.9–77.4) in post-VVS group. Additionally, it was not correlated with the sampling times within 24 hours after the episodes.

Conclusions:

The plasma level of pro-BNP has a limited clinical value in differentiating seizure and vasovagal syncope in adults. However, the more validated results with a large population should be sought in the future studies to confirm its value.