Causes Of Transient Loss Of Consciousness Research Articles

Predicting the cause of seizures using features extracted from interactions with a virtual agent

ObjectiveA clinical decision tool for Transient Loss of Consciousness (TLOC) could reduce currently high misdiagnosis rates and waiting times for specialist assessments. Most clinical decision tools based on patient-reported symptom inventories only distinguish between two of the three most common causes of TLOC (epilepsy, functional /dissociative seizures, and syncope) or struggle with the particularly challenging differentiation between epilepsy and FDS. Based on previous research describing differences in spoken accounts of epileptic seizures and FDS seizures, this study explored the feasibility of predicting the cause of TLOC by combining the automated analysis of patient-reported symptoms and spoken TLOC descriptions. MethodParticipants completed an online web application that consisted of a 34-item medical history and symptom questionnaire (iPEP) and spoken interaction with a virtual agent (VA) that asked eight questions about the most recent experience of TLOC. Support Vector Machines (SVM) were trained using different combinations of features and nested leave-one-out cross validation. The iPEP provided a baseline performance. Inspired by previous qualitative research three spoken language based feature sets were designed to assess: (1) formulation effort, (2) the proportion of words from different semantic categories, and (3) verb, adverb, and adjective usage. Results76 participants completed the application (Epilepsy = 24, FDS = 36, syncope = 16). Only 61 participants also completed the VA interaction (Epilepsy = 20, FDS = 29, syncope = 12). The iPEP model accurately predicted 65.8 % of all diagnoses, but the inclusion of the language features increased the accuracy to 85.5 % by improving the differential diagnosis between epilepsy and FDS. ConclusionThese findings suggest that an automated analysis of TLOC descriptions collected using an online web application and VA could improve the accuracy of current clinical decisions tools for TLOC and facilitate clinical stratification processes (such as ensuring appropriate referral to cardiological versus neurological investigation and management pathways).

Syncope Diagnosis at Referral to a Tertiary Syncope Unit: An in-Depth Analysis of the FAST II.

A substantial number of patients with a transient loss of consciousness (T-LOC) are referred to a tertiary syncope unit without a diagnosis. This study investigates the final diagnoses reached in patients who, on referral, were undiagnosed or inaccurately diagnosed in secondary care. This study is an in-depth analysis of the recently published Fainting Assessment Study II, a prospective cohort study in a tertiary syncope unit. The diagnosis at the tertiary syncope unit was established after history taking (phase 1), following autonomic function tests (phase 2), and confirming after critical follow-up of 1.5-2 years, with the adjudicated diagnosis (phase 3) by a multidisciplinary committee. Diagnoses suggested by the referring physician were considered the phase 0 diagnosis. We determined the accuracy of the phase 0 diagnosis by comparing this with the phase 3 diagnosis. 51% (134/264) of patients had no diagnosis upon referral (phase 0), the remaining 49% (130/264) carried a diagnosis, but 80% (104/130) considered their condition unexplained. Of the patients undiagnosed at referral, three major causes of T-LOC were revealed: reflex syncope (69%), initial orthostatic hypotension (20%) and psychogenic pseudosyncope (13%) (sum > 100% due to cases with multiple causes). Referral diagnoses were either inaccurate or incomplete in 65% of the patients and were mainly altered at tertiary care assessment to reflex syncope, initial orthostatic hypotension or psychogenic pseudosyncope. A diagnosis of cardiac syncope at referral proved wrong in 17/18 patients. Syncope patients diagnosed or undiagnosed in primary and secondary care and referred to a syncope unit mostly suffer from reflex syncope, initial orthostatic hypotension or psychogenic pseudosyncope. These causes of T-LOC do not necessarily require ancillary tests, but can be diagnosed by careful history-taking. Besides access to a network of specialized syncope units, simple interventions, such as guideline-based structured evaluation, proper risk-stratification and critical follow-up may reduce diagnostic delay and improve diagnostic accuracy for syncope.

Transient loss of consciousness in children: Syncope or epileptic seizure?

Background & Objective: Transient loss of consciousness (TLOC) is often benign from syncope but may be due to epileptic seizure. In this study, we aimed to evaluate the clinical differences between TLOC from epileptic seizures and syncope. Methods: The medical records of 300 children with TLOC were analyzed retrospectively. Age, sex, clinical symptoms, trigger factors, laboratory findings, ECG, ECHO, EEG and neuroimaging findings, as well as the causes of TLOC were reviewed. Results: Out of the 300 children admitted with TLOC, 288 (96%) were diagnosed as syncope. Of these patients, 231 (77%) were diagnosed as vasovagal syncope, 19 (6.3%) as orthostatic hypotension, and 38 (12.7%) as unclassifiable syncope. Twelve (4.2%) patients were diagnosed with epilepsy. Patients with epilepsy showed significantly higher rates of collapse and eye deviation during TLOC, as well as occurring in sitting and supine position (p=0.012, p=0.039, p=0.03 respectively). Conclusion: For a differential diagnosis, TLOC accompanied by collapse, eye deviation and occurrence in sitting or supine position are suggestive of epilepsy.

#3079 Investigating the feasibility of automating the differential diagnosis of transient loss of consciousness

BackgroundThere are three common causes of Transient Loss of Consciousness (TLOC), syncope, epileptic and psychogenic nonepileptic seizures (PNES). Many individuals who have experienced TLOC initially receive an incorrect diagnosis and inappropriate treatment. Whereas syncope can be distinguished from the other two causes relatively easily with a small number of yes/no questions, the differentiation of the other two causes of TLOC is more challenging. Previous qualitative research based on the methodology of Conversation Analysis has demonstrated that epileptic and nonepileptic seizures are described differently when patients talk to clinicians about their TLOC experiences. One particularly prominent difference is that epileptic seizure descriptions are characterised by more formulation effort than accounts of nonepileptic seizures.AimThis research investigates whether features likely to reflect the level of formulation effort can be automatically elicited from audio recordings and transcripts of speech and used to differentiate between epileptic and nonepileptic seizures.MethodVerbatim transcripts of conversations between patients and neurologists were manually produced from video and audio recordings of interactions with 45 patients (21 epilepsy and24 PNES). The subsection of each transcript containing the patients account of their first seizure was manually extracted for the analysis. Seven automatically detectable features were designed as markers of formulation effort. These features were used to train a Random Forest machine learning classifier.ResultsThere were significantly more hesitations and repetitions in descriptions of first epileptic than nonepileptic seizures. Using a nested leave-one-out cross validation approach, 71% of seizures were correctly classified by the Random Forest classifier.ConclusionsThis pilot study provides proof of principle that linguistic features that have been automatically extracted from audio recordings and transcripts could be used to distinguish between epileptic seizures and PNES and thereby contribute to the differential diagnosis of TLOC. Future research should explore whether additional observations can be incorporated into a diagnostic stratification tool. Moreover, future research should explore the performance of these features when they have been extracted from transcripts produced by automatic speech recognition and when they are combined with additional information provided by patients and witnesses about seizure manifestations and medical history.

Feasibility of using an automated analysis of formulation effort in patients’ spoken seizure descriptions in the differential diagnosis of epileptic and nonepileptic seizures

ObjectiveThere are three common causes of Transient Loss of Consciousness (TLOC), syncope, epileptic and psychogenic nonepileptic seizures (PNES). Many individuals who have experienced TLOC initially receive an incorrect diagnosis and inappropriate treatment. Whereas syncope can be distinguished relatively easily with a small number of “yes”/”no” questions, the differentiation of the other two causes of TLOC is more challenging. Previous qualitative research based on the methodology of Conversation Analysis has demonstrated that the descriptions of epileptic seizures contain more formulation effort than accounts of PNES. This research investigates whether features likely to reflect the level of formulation effort can be automatically elicited from audio recordings and transcripts of speech and used to differentiate between epileptic and nonepileptic seizures. MethodVerbatim transcripts of conversations between patients and neurologists were manually produced from video and audio recordings of 45 interactions (21 epilepsy and 24 PNES). The subsection of each transcript containing the person's account of their first seizure was manually extracted for the analysis. Seven automatically detectable features were designed as markers of formulation effort. These features were used to train a Random Forest machine learning classifier. ResultThere were significantly more hesitations and repetitions in descriptions of epileptic than nonepileptic seizures. Using a nested leave-one-out cross validation approach, 71% of seizures were correctly classified by the Random Forest classifier. DiscussionThis pilot study provides proof of principle that linguistic features that have been automatically extracted from audio recordings and transcripts could be used to distinguish between epileptic seizures and PNES and thereby contribute to the differential diagnosis of TLOC. Future research should explore whether additional observations can be incorporated into a diagnostic stratification tool and compare the performance of these features when they are combined with additional information provided by patients and witnesses about seizure manifestations and medical history.

Protocolo diagnóstico y manejo clínico de la pérdida transitoria de conciencia

Transient loss of consciousness (TLoC) is a loss of consciousness with an abrupt onset, short duration, and spontaneous and complete recovery. TLoC is very common reason for clinical consultation. Clinical manifestation is a key factor in differential diagnosis, requiring a proper anamnesis and physical examination. The most frequent causes of TLoC are, firstly, neurally mediated syncope, followed by epileptic seizures or functional disorders. The goal of the current protocol is to provide key factors in order to guide etiological diagnosis and clinical management of TLoC.

Syncope or seizure or even other types of transient loss of consciousness ? A differential-diagnostic challenge

Background: Syncope and seizure are the most common clinical manifestations of transient loss of consciousness (TLOC). The differential diagnosis may be quite difficult and often causes misdiagnoses with consequently inappropriate treatment attempts. TLOC defines the various, rather frequent conditions with an abrupt onset of apparent loss of consciousness. Within a short time (i.e. within minutes), patients have a spontaneous and complete recovery. During TLOCs there is: 1) loss of normal motor control either with flaccid muscle tone or with stiffness that may be accompanied by jerking movements, 2) loss of postural control associated with falls, and 3) unresponsiveness and amnesia for the time period of the event. It is of clinical importance to establish the cause of TLOC. The most common causes of non-traumatic TLOC are syncope and seizure. While differentiation between these two causes has significant therapeutic consequences, it is often difficult, particularly if patients have a convulsive syncope. The following are ways to recognize causes of TLOC.

Syncope or seizure or even other types of transient loss of consciousness ? A differential-diagnostic challenge

Background: Syncope and seizure are the most common clinical manifestations of transient loss of consciousness (TLOC). The differential diagnosis may be quite difficult and often causes misdiagnoses with consequently inappropriate treatment attempts. TLOC defines the various, rather frequent conditions with an abrupt onset of apparent loss of consciousness. Within a short time (i.e. within minutes), patients have a spontaneous and complete recovery. During TLOCs there is: 1) loss of normal motor control either with flaccid muscle tone or with stiffness that may be accompanied by jerking movements, 2) loss of postural control associated with falls, and 3) unresponsiveness and amnesia for the time period of the event. It is of clinical importance to establish the cause of TLOC. The most common causes of non-traumatic TLOC are syncope and seizure. While differentiation between these two causes has significant therapeutic consequences, it is often difficult, particularly if patients have a convulsive syncope. The following are ways to recognize causes of TLOC.

Evaluation and management of patients with seizures in the emergency department: a one-year analysis

Introduction. Transient loss of consciousness (TLoC) encompasses symptoms caused by either syncope, seizures or psycogenic disorders which are all frequent in the emergency department (ED). The study aims to determine the prevalences of causes of TLoC in the ED, analyse the characteristics of patients with seizures or established epilepsy in particular and estimate the level of evaluation and management they receive in respect to available international guidelines. Materials and methods. The data was cross-sectional and was retrieved from the local database of Vilnius University Hospital Santaros Klinikos from January 1st to December 31st 2016. Adult patients with diagnoses (coded in the International Statistical Classification of Diseases and Related Health Problems, ICD-10-AM) of syncope (R55), epilepsy (G40) or other and unspecified convulsions (R56.8) assigned either by the emergency medical services or the ED staff were involved in the study (315 cases). The data was analysed with Microsoft Excel v16.0 and IBM SPSS Statistics v20, two-sided Fisher’s exact and Mann-Whitney U tests were employed (p<0.05). Results. As diagnoses provided by emergency services and the ED staff were conflicting, only the latter were used for the assortment. The majority of patients brought to the ED with TLoC (average age 53.5±20.8) had syncope or collapse (134, 42.5%), 54 (17.1%) had epilepsy, and 32 (10.2%) had other and unspecified convulsions, which encompass mostly new-onset seizures. The mean age of patients with established epilepsy was 47.6±15.7 and significantly (p=0.014) lower than due to other causes. Male gender predominated in all-cause seizures (odds ratio OR=1.7; 95% confidence interval CI=1.0-2.9, p=0.042). Laboratory blood tests were commonly used for all patients, but patients with epilepsy received computed tomography (CT) scans and were hospitalized more often than other patients (p<0.001, p=0.002, respectively). Both an electrocardiography (ECG) and troponin blood levels (both often received after syncope and collapse) were evaluated less frequently in these cases, however (p<0.001). Focal seizures (32, 59.3%) and alcohol-related metabolic seizures (8, 14.8%) were most common with epilepsy; unknown or unspecified (22, 68.8%) and generalized (6, 18.8%) – with new-onset seizures. For outpatients with epilepsy, alcohol abstinence (16, 44.4%) and everyday (lifestyle, work etc.) recommendations (13, 36.1%) were most common, treatment was often modified (14, 38.9%). Outpatients with seizures but no diagnosed epilepsy were most often advised to consult a neurologist, receive an electroencephalography (EEG) (19, 76.0% and 11, 44.0%, respectively), and abstain from alcohol ( 11, 44.0%), but treatment was almost never prescribed. Conclusions. Syncope and collapse caused most cases of TLoC, followed by established epilepsy and new-onset seizures. Patients with epilepsy were younger than in other cases and in assessing all presentations with seizures, male gender predominated. The evaluative practices and care complied with selected international guidelines in most cases, except for some approaches related to neuroimaging and information deliverance.

Temporal Relationship of Asystole to Onset of Transient Loss of Consciousness in Tilt-Induced Reflex Syncope.

The purpose of this study was to investigate the relationship between the onset of asystole and transient loss of consciousness (TLOC) in tilt-induced reflex syncope and estimate how often asystole was the principal cause ofTLOC. The presence of asystole in vasovagal syncope (VVS) may prompt physicians to consider pacemaker therapy for syncope prevention, but the benefit of pacing is limited in VVS. We evaluated electrocardiography, electroencephalography, blood pressure, and clinical findings during tilt-table tests. Inclusion required TLOC (video), electroencephalographic slowing, accelerating blood pressure decrease, and an RR interval≥3 s. We excluded cases with nitroglycerin provocation. Asystole after onset of TLOC (group A) or within 3 s before TLOC (group B) was unlikely to cause TLOC, but an earlier start of asystole (group C) could be the cause of TLOC. In one-third of 35 cases (groups A [n= 9] and B [n = 3]), asystole was unlikely to be the primary cause of TLOC. The median of the mean arterial pressure at the onset of asystole was higher when asystole occurred early (45.5 mmHg, group C) than when it occurred late (32.0 mmHg, groups A and B), which suggests that vasodepression was not prominent at the start of asystole in early asystole, further suggesting that early asystole was the prime mechanism of syncope. In one-third of cases of tilt-induced asystolic reflex syncope, asystole occurred too late to havebeenthe primary cause of TLOC. Reliance on electrocardiography data only is likely to overestimate the importanceofasystole.

Panic symptoms in transient loss of consciousness: Frequency and diagnostic value in psychogenic nonepileptic seizures, epilepsy and syncope

PurposePrevious studies suggest that ictal panic symptoms are common in patients with psychogenic nonepileptic seizures (PNES). This study investigates the frequency of panic symptoms in PNES and if panic symptoms, just before or during episodes, can help distinguish PNES from the other common causes of transient loss of consciousness (TLOC), syncope and epilepsy. MethodsPatients with secure diagnoses of PNES (n=98), epilepsy (n=95) and syncope (n=100) were identified using clinical databases from three United Kingdom hospitals. Patients self-reported the frequency with which they experienced seven symptoms of panic disorder in association with their episodes. A composite panic symptom score was calculated on the basis of the frequency of symptoms. Results8.2% of patients with PNES reported “never” experiencing any of the seven panic symptoms in their episodes of TLOC. Patients with PNES reported more frequent panic symptoms in their attacks than those with epilepsy (p<0.001) or syncope (p<0.001), however, patients with PNES were more likely “rarely” or “never” to report five of the seven-ictal panic symptoms than “frequently” or “always” (45–69% versus 13–29%). A receiver operating characteristic analysis demonstrated that the composite panic symptom score distinguished patients with PNES from the other groups (sensitivity 71.1%, specificity 71.2%), but not epilepsy from syncope. ConclusionsPatients with PNES report TLOC associated panic symptoms more commonly than those with epilepsy or syncope. Although panic symptoms are reported infrequently by most patients with PNES, a composite symptom score may contribute to the differentiation between PNES and the other two common causes of TLOC.

Evaluation of the child with syncope

Abstract Transient loss of consciousness (TLOC) is spontaneous loss of consciousness with complete recovery; there is temporary impairment of brain function associated with loss of awareness, loss of responsiveness, and loss of memory. Syncope is the most common cause of transient loss of consciousness in children. Whilst syncope is potentially easy to understand using applied physiology, therapeutic opportunities are often missed, leading to avoidable morbidity and disability. In this article we will discuss the causes of TLOC and focus on the evaluation and management of syncope and orthostatic intolerance in children and young people.

Syncope: Approach to diagnosis

Syncope is a transient loss of consciousness (LOC) due to transient global cerebral hypoperfusion characterized by rapid onset, short duration, and spontaneous complete recovery. Here, the term transient LOC encompasses all disorders characterized by self-limited LOC irrespective of the mechanism. Central point in pathophysiology of the development of syncope is fall in systemic blood pressure (BP) with a decrease in global cerebral blood flow. The evaluation and treatment of syncope are very challenging because syncope is not the only cause of transient LOC. Moreover, symptoms of syncope are fleeting, patient is usually asymptomatic at the time of evaluation, and most of the events are often unwitnessed. The guiding principle of assessment is to differentiate syncope from other causes of transient LOC and the more benign causes of syncope from the potentially serious ones. Initial assessment of syncope consists of a detailed history and examination complemented by 12-lead electrocardiography and supine and standing BP. If the cause is suspected, then further investigations may be needed to confirm the particular disorder. A deliberate approach based on initial risk stratification is more likely to give a correct diagnosis. Despite the difficulties, a thorough evaluation of the cause of syncope is warranted in all patients, not just in those deemed to be at high mortality risk. The goal in every case should be to determine the cause with sufficient confidence to provide a reliable assessment of prognosis and treatment options.

Lifetime Prevalence of Transient Loss of Consciousness in an Urban Russian Population.

BackgroundMost international studies on epidemiology of transient loss of consciousness (TLC) were performed many years ago. There are no data about the lifetime prevalence of TLC in Russia.ObjectiveTo identify the lifetime prevalence and presumed mechanisms of TLC in an urban Russian population.Methods1796 individuals (540 males [30.1%] and 1256 females [69.9%]) aged 20 to 69 years (mean age 45.8 ± 11.9 years) were randomly selected and interviewed within the framework of multicentre randomised observational trial.ResultsThe overall prevalence of TLC in the studied population was 23.3% (418/1796), with the highest proportion (28%) seen in 40-49 year age group. TLC was significantly more common in women than in men (27.5% vs 13.5%). The mean age of patients at the time of the first event was 16 (11; 23) years, with 333 (85%) individuals experiencing the first episode of TLC under 30 years. The average time after the first episode of TLC was 27 (12; 47) years. The following mechanisms of TLC were determined using the questionnaire: neurally-mediated syncope (56.5%), arrhythmogenic onset of syncope (6.0%), nonsyncopal origin of TLC (1.4%), single episode during lifetime (2.1%). Reasons for TLC remained unidentified in 34% cases. 27 persons (6.5%) reported a family history of sudden death, mainly patients with presumably arrhythmogenic origin (24%).ConclusionOur findings suggest that the overall prevalence of TLC in individuals aged 20-69 years is high. The most common cause of TLC is neurally-mediated syncope. These data about the epidemiology can help to develop cost-effective management approaches to TLC.

Is it syncope? Differential diagnosis of transient loss of consciousness in the emergency department

Introduction. To define with certainty syncope, global cerebral hypoperfusion is needed. However, in the Emergency Department (ED), syncope can be sometimes hardly distinguished by other causes of transient loss of consciousness (TLOC), thus making global cerebral hypoperfusion an ineffectual criterion. The aim of the present study was to evaluate how frequently, in the ED setting, doctors are unconfident of a syncopal etiology. Matherials and Methods. Among a period of three months all consecutive patients evaluated in a single city hospital ED for possible syncopal events were selected. Among those, the authors have analyzed the ones for which the ED physician was not confident with the possible etiology of the loss of consciousness. Results. 213 patients with possible syncopewere enrolled. Among 45 of those, the ED physicianwas not sure of a syncopal etiology. In further 34 cases he was doubtful if the patient had had a definite TLOC, while for 11 patients he could not be decide between syncope or another cause of TLOC (mainly epilepsy). Conclusions. For roughly 20% of patients evaluated in the ED for possible TLOC the ED physician cannot surely differentiate between syncope and other TLOC. The limits of the present syncope definition should be recognized and a consensus for a new syncope definition to be used in the ED could be useful.

History taking as a diagnostic test in patients with syncope: developing expertise in syncope.

Transient loss of consciousness (T-LOC) is very common and caused by many disorders spanning multiple specialties with consequences varying from benign to lethal, necessitating an accurate, efficient diagnostic work-up. The European Society of Cardiology Guidelines on Syncope recommends that the initial work-up of suspected syncope consists of history taking, a physical examination, and ECG. The emphasis on taking a history is justified by its high diagnostic yield.1,2 Surprisingly, there is relatively little research on how data from the medical history are collected and analysed in syncope patients. While a few studies have described evidence-based point scores for diagnosing patients with syncope, the added value of expert history taking in syncope has received less attention.2 The diagnostic yield of the initial work-up by non-expert physicians in patients with T-LOC according to the ESC guidelines is reported to be 60–70% with history taking as the main factor,3 while after standardized evaluation in dedicated units (syncope units) ∼85% of patients are reported to be diagnosed.4,5 The diagnostic yield of expert history taking in patients who remain undiagnosed after standardized approaches according to the management model proposed by the ESC is unknown. The focus of this current opinion is on the roles of evidence-based point scores and expert history taking in diagnosing suspected syncope. An effective diagnostic strategy for syncope requires knowledge of other causes of T-LOC and hence requires training or experience in relevant aspects of cardiology, neurology, internal medicine, emergency medicine, paediatrics, geriatrics, and psychiatry. These specialties are all within general internal medicine, which has become fragmented leading to decrease in the broad skills of history taking and physical examination. The majority of patients with suspected syncope have vasovagal or other types of reflex syncope like situational or carotid sinus syncope. In the emergency …

38 * Effectiveness of ECG-based triage in older patients with TLoC attending a rapid access blackouts triage clinic: conduction tissue abnormalities predict a higher mortality, recurrent TLoC and a good response to cardiac pacing

Introduction: Transient loss of consciousness (TLOC) is common and increasing rapidly with a rising burden on health care expenditure. It often leads to hospitalisation in the elderly population. In the elderly, electrocardiographic (ECG) findings suggesting conduction tissue disease are frequently found, but it is not always clear if they accurately represent the underlying cause of TLOC. We therefore compared outcomes in elderly patients attending the rapid access blackout clinic (RABTC) with conduction tissue abnormalities (ECG-CTA) with patients attending with a normal ECG. Methods: Our twice-weekly RABTC is staffed by specialist nurses and a cardiologist. Detailed clinical assessment is given using a secure web-based 13 page RABTC Assessment Tool. Risk is assessed with 8 “Red Flags”, which include an abnormal ECG. We sequentially selected 85 patients with normal ECG, Group A, and 65 patients with ECG-CTA, Group B, >65 years of age, presenting to RABTC between 1st January 2007 till 1st January 2013 where all had 3 years of follow-up. Group B patients had ECG-CTA (38 had first degree AV block, 15 had left axis deviation, 8 had Right Bundle branch block, 14 had Left bundle branch block,). Results: 2586 patients were assessed in the RABTC during the period. Mean age 56±10 yrs, 51% female (F). Group A, Age 75±7sd, 62% F, Group B Age 77±8sd, 51% F. The rate of recurrent TLOC was higher in Group B, (73% v 81%, P<0.004), significant injury/fracture was similar, (45% v 51%), use of implantable ECG recorders was similar, (26 v 24%), and annual rate of hospital admission was similar, (1.77 v 2.25 /patient/year). 12 Group A patients received pacemakers, and 31 Group B patients (Group B1). Amongst Group B1 patients, pacing relieved symptoms and prevented re-admission in 20 (64%). Three-year all cause mortality overall in Group A was 6% and in Group B 15% (p<0.03), but pacing did not seem to alter mortality risk (Group B1=14%, Group B2=16%, ns) Conclusion: Amongst TLOC patients referred to an RABTC for clinical and ECG assessment, baseline characteristics are similar, but the finding of ECG-CTA confers a poor outcome. Pacing appears to reduce admission and relieve symptoms but not mortality.

Clinical history: the cornerstone for defining the cause of syncope

Syncope is a transient loss of consciousness (LOC) due to transient global cerebral hypoperfusion characterized by rapid onset, short duration, and spontaneous complete recovery. However, there are no signs or symptoms specific for LOC due to global cerebral hypoperfusion, and other diseases, commonly defined as non-syncopal LOC, can induce transient LOC with other mechanisms. Moreover, since there are many causes of transient LOC, an adequate method in taking clinical history, which is the cornerstone of diagnosing patients with transient LOC, must be utilized. The first question to be answered is whether the patient had a real LOC, characterized by loss of postural control and unresponsiveness. Therefore, events with similar clinical features, such as falls, drop attack, etc., should be ruled out. Once a LOC is diagnosed, the questions that need an answer are: was LOC with rapid onset and short duration? Did the patient recover spontaneously? If the answers to these questions are positive (therefore, after exclusion of affections such as coma, cardiac arrest, etc.), we are dealing with a transient LOC, which can be an expression of syncope or non-syncopal LOC. From a methodological point of view, we should try to exclude a non-syncopal LOC. Once syncope is diagnosed, we should define the cause. There are some findings in the clinical history that can be considered diagnostic of the cause of syncope. In many other situations, the findings do not permit a definite diagnosis to be made but suggest some causes and, therefore, specific examinations.

Neurologische und psychiatrische Abklärung in der Synkopendiagnostik

A transient loss of consciousness (TLOC) may have different causes. The term syncope is restricted to an underlying sudden decrease in cerebral perfusion. In most cases, syncopes or other causes of TLOC are recognizable by a basic diagnostic evaluation (history taking, physical examination, ECG, and supine and upright blood pressure measurements). Cues for epileptic seizures, e.g., delayed recovery, should prompt an extended search for an epileptic focus. Unusual features of the attacks without any hint for a syncopal or an epileptic origin require the psychiatric inspection of suspected dissociative (psychogenic) seizures. Neurogenic orthostatic hypotension results from sympathetic failure. The underlying disease (Parkinson's disease, pure autonomic failure, autonomic neuropathy, etc.) has to be identified by neurological examinations.

NICE guideline: transient loss of consciousness (blackouts) in adults and young people

Transient loss of consciousness (TLoC) is loss of consciousness with complete recovery. It is commonly described by the patient as a blackout. TLoC is very common and people who experience it may present to GPs during surgery hours or out of hours, or they may be referred from the ambulance services or the emergency department. There are a number of potential causes of TLoC: The diagnosis of the underlying cause is often inaccurate, inefficient, and delayed, and misdiagnosis is common. NICE guideline CG1091 aims to define the appropriate pathways for the assessment of patients who experience TLoC, in order to obtain the correct underlying diagnosis quickly, efficiently, and cost-effectively, and to tailor a management plan to suit their true diagnosis. The guideline includes advice on the management of uncomplicated faint/situational syncope and orthostatic hypotension, as well as on detailed testing and assessment of those people considered to have a cardiovascular cause for their TLoC. ### Initial assessment The guidance most relevant to GPs is likely to concern those areas related to initial assessment in order to determine whether the person has had TLoC, the possible causes of it, and the appropriate next steps. #### History Ask the person who has had the suspected TLoC, as well as any witnesses, to describe what happened before, during, and after the event. Try to contact, by telephone, any witnesses who are not present at the consultation. Record details about: