Diagnostic Value of Neurological Studies in Diagnosing Syncope: A Systematic Review

Syncope in the Emergency Department: A Practical Approach

Syncope is a common condition encountered in the emergency department (ED), accounting for about 0.6-3% of all ED visits. Despite its high frequency, a widely accepted management strategy for patients with syncope in the ED is still missing. Since syncope can be the presenting condition of many diseases, both severe and benign, most research efforts have focused on strategies to obtain a definitive etiologic diagnosis. Nevertheless, in everyday clinical practice, a definitive diagnosis is rarely reached after the first evaluation. It is thus troublesome to aid clinicians' reasoning by simply focusing on differential diagnoses. With the current review, we would like to propose a management strategy that guides clinicians both in the identification of conditions that warrant immediate treatment and in the management of patients for whom a diagnosis is not immediately reached, differentiating those that can be safely discharged from those that should be admitted to the hospital or monitored before a final decision. We propose the mnemonic acronym RED-SOS: Recognize syncope; Exclude life-threatening conditions; Diagnose; Stratify the risk of adverse events; Observe; decide on the Setting of care. Based on this acronym, in the different sections of the review, we discuss all the elements that clinicians should consider when assessing patients with syncope.

Diagnostic approaches to syncope in Internal Medicine Departments and their effect on mortality

Most data on mortality and investigational approaches to syncope comes from patients presented to emergency departments (ED). The aim of this study is to report intermediate term mortality in syncope patients admitted to Internal Medicine Departments and whether different diagnostic approaches to syncope affect mortality. Methods and results A single-center retrospective-observational study conducted at the Tel Aviv "Sourasky" Medical Center. Data was collected from electronic medical records (EMRs), from January 2010 to December 2020. We identified 24,021 patients, using ICD-9-CM codes. Only 7967 syncope patients were admitted to Internal Medicine Departments and evaluated. Logistic regression models were used to determine the effects of diagnostic testing per patient in each department on 30-day mortality and readmission rates. All-cause 30-day mortality rate was 4.1%. There was a significant difference in the number of diagnostic tests performed per patient between the different departments, without affecting 30-day mortality. The 30-day readmission rate was 11.4%, of which 4.4% were a result of syncope. Conclusion Syncope patients admitted to Internal Medicine Departments show a 30-day all-cause mortality rate of ∼4%. Despite the heterogeneity in the approach to the diagnosis of syncope, mortality is not affected. This novel information about syncope patients in large Internal Medicine Departments is further proof that the diagnosis of syncope requires a logic, personalized approach that focuses on medical history and a few tailored, diagnostic tests.

Cardiac and Vascular Causes of Syncope and Atherosclerosis

PURPOSE OF REVIEW

Among the most common causes of cardiac syncope are arrhythmias and ischemic heart disease, both of which can coexist. The purpose of this review is to discuss the main causes of cardiac and vascular syncope related to atherosclerosis, its epidemiological and clinical aspects, warning signs, and initial approach.

RECENT FINDINGS

Cardiac syncope may have a frequency of up to 34% in elderly people. Atherosclerosis-related causes of cardiac and vascular syncope may be due to cardiac arrhythmia and/or structural impairment of the heart or arteries. Late ventricular tachycardia and late-onset high-grade atrioventricular block associated with myocardial ischemia may occur with syncope, which is related to higher mortality. Besides ventricular dysfunction, concentric remodeling is also a prognostic factor. In calcific degenerative aortic stenosis, syncope carries a worse prognosis than the other cardinal signs. Cardiac syncope has a high recurrence and mortality rate. There are red flag alerts that must be considered in risk stratification.

Syncope and the aging patient: Navigating the challenges

Syncope in the elderly patient is a common presentation and the most common causes are usually non-cardiac. Older adults however are more challenging dilemmas as their presentation is complicated by co-morbidities, mainly cardiovascular and neurodegenerative disorders. Frailty and cognitive impairment add to the ambiguity of the presentation, and polypharmacy is often a major modifiable contributing factor. Vasovagal syncope is a common presentation throughout life even as we age. It has a favorable prognosis and conservative management usually suffices. Vasovagal syncope in this population may be misdiagnosed as accidental falls and is frequently associated with injury, as is carotid sinus syndrome. The initial approach to these patients entails a detailed history and physical examination including a comprehensive medication history, orthostatic vital signs, and a 12-lead electrocardiogram. Further cardiac and neuroimaging rarely helps, unless directed by specific clinical findings. Head-up tilt testing and carotid sinus massage retain their diagnostic accuracy and safety in the elderly, and implantable loop recorders provide important information in many elderly patients with unexplained falls and syncope. The starting point in management of this population with non-cardiac syncope is attempting to withdraw unnecessary vasoactive and psychotropic medications. Non-pharmacologic and pharmacologic therapy for syncope in the elderly has limited efficacy and safety concerns. In selected patients, pacemaker therapy might offer symptomatic relief despite lack of efficacy when vasodepression is prominent. An approach focused on primary care with targeted specialist referral seems a safe and effective strategy.

Resource utilisation among patients with syncope presenting to the emergency department

BACKGROUND

Syncope is a common problem encountered in the emergency department (ED) and a significant source of ED resource utilisation, including advanced imaging modalities. Current guidelines do not recommend routine Computed Tomography (CT) imaging of the head for patients seen in the ED due to syncope.

OBJECTIVE

In this study, we investigate resource allocation in the ED for syncope-related visits, including advanced imaging modalities using a large national database.

OUTCOMES ANALYSIS

Data from the CDC's National Hospital Ambulatory Medical Care Survey (NHAMCS) for years 2008-2017 were compiled and analysed. Intrinsic survey and constructed variables were utilised to identify and investigate all syncope-related ED visits in the United States during the study period that met study criteria. Appropriate bivariate and multivariate statistical analyses were applied in order to identify and compare the resource utilisation, demographics, and ED visit dynamics of syncope and non-syncope-related ED visits.

RESULTS

During the study period, there were over 15 million ED visits for syncope. A high percentage of syncope visits received head CT compared with non-syncope visits (34% vs. 4.5%, P > .001). When investigated by age-grouping utilisation of head CT ranged from 26.5 (95% CI 18.9-27.5) for ages 18-40 to as high as 40.2% (95% CI 33.8-47.1) for ages 80 and higher. Compared with non-syncope ED visits, syncope-related ED visits were older and more likely to have Medicare or private insurance.

CONCLUSION

Syncope continues to be a large and growing share of visits to US EDs. Despite well-supported, evidence-based recommendations that do not recommend routine utilisation of head CT in syncope-related ED visits, these data suggest that emergency physicians routinely over-utilise this modality. More specific guidelines may be required to help reduce the use of imaging studies for patients who present to the ED with syncope.

Electrophysiology studies for predicting atrioventricular block in patients with syncope: A systematic review and meta-analysis

BACKGROUND

Syncope may be caused by intermittent complete heart block in patients with bundle branch block. Electrophysiology studies (EPS) testing for infra-Hisian heart block are recommended by the European Society of Cardiology syncope guidelines on the basis of decades-old estimates of their negative predictive values (NPVs) for complete heart block.

OBJECTIVE

The aim of this study was to determine the NPV of EPS for complete heart block in patients with syncope and bundle branch block.

METHODS

We searched MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, and CINAHL without language restriction from database inception to October 2019 for Medical Subject Headings terms and keywords related to "syncope," "heart block," and "programmed electrical stimulation." A random effects meta-analysis was conducted with a primary outcome of the proportion of patients with a negative EPS who later presented with complete heart block, diagnosed with surface electrocardiographic (ECG) recordings vs continuous implantable cardiac monitor (ICM).

RESULTS

Ten reports contained 12 cohorts with 639 patients who met the inclusion criteria. The mean age was 69 ± 7 years; 35% ± 10% were women; and 85% of patients had bifascicular block. Seven cohorts recorded clinical outcomes with external ECG recordings, and 5 cohorts featured ICMs. The mean prespecified His-to-ventricle interval criterion was ≥70 ms. In studies featuring surface ECG recordings, there were 7% (95% confidence interval 7%-17%) patients who developed complete heart block compared with 29% (95% confidence interval 24%-35%) in the studies featuring ICM (P = .0001).

CONCLUSION

The NPV of EPS in patients with syncope and bundle branch block is 0.71, sufficiently low to question its use.

Canadian Cardiovascular Society Clinical Practice Update on the Assessment and Management of Syncope

Syncope is a symptom that occurs in multiple settings and has a variety of underlying causes, ranging from benign to life threatening. Determining the underlying diagnosis and prognosis can be challenging and often results in an unstructured approach to evaluation, which is ineffective and costly. In this first ever document, the Canadian Cardiovascular Society (CCS) provides a clinical practice update on the assessment and management of syncope. It highlights similarities and differences between the 2017 American College of Cardiology/American Heart Association/Heart Rhythm Society and the 2018 European Society of Cardiology guidelines, draws on new data following a thorough review of medical literature, and takes the best available evidence and clinical experience to provide clinical practice tips. Where appropriate, a focus on a Canadian perspective is emphasized in order to illuminate larger international issues. This document represents the consensus of a Canadian panel comprised of multidisciplinary experts on this topic with a mandate to formulate disease-specific advice. The primary writing panel wrote the document, followed by peer review from the secondary writing panel. The CCS Guidelines Committee reviewed and approved the statement. The practice tips represent the consensus opinion of the primary writing panel authors, endorsed by the CCS. The CCS clinical practice update on the assessment and management of syncope focuses on epidemiology, the initial evaluation including risk stratification and disposition from the emergency department, initial diagnostic work-up, management of vasovagal syncope and orthostatic hypotension, and syncope and driving.

The Yield of Computed Tomography of the Head Among Patients Presenting With Syncope: A Systematic Review

BACKGROUND

Overuse of head computed tomography (CT) for syncope has been reported. However, there is no literature synthesis on this overuse. We undertook a systematic review to determine the use and yield of head CT and risk factors for serious intracranial conditions among syncope patients.

METHODS

We searched Embase, Medline, and Cochrane databases from inception until June 2017. Studies including adult syncope patients with part or all of patients undergoing CT head were included. We excluded case reports, reviews, letters, and pediatric studies. Two independent reviewers screened the articles and collected data on CT head use, diagnostic yield (proportion with acute hemorrhage, tumors or infarct), and risk of bias. We report pooled percentages, I² , and Cochran's Q-test.

RESULTS

Seventeen articles with 3,361 syncope patients were included. In eight ED studies (n = 1,669), 54.4% (95% confidence interval [CI] = 34.9%-73.2%) received head CT with a 3.8% (95% CI = 2.6%-5.1%) diagnostic yield and considerable heterogeneity. In six in-hospital studies (n = 1,289), 44.8% (95% CI = 26.4%-64.1%) received head CT with a 1.2% (95% CI = 0.5%-2.2%) yield and no heterogeneity. In two articles, all patients had CT (yield 2.3%) and the third enrolled patients ≥ 65 years old (yield 7.7%). Abnormal neurologic findings, age ≥ 65 years, trauma, warfarin use, and seizure/stroke history were identified as risk factors. The quality of all articles referenced was strong.

CONCLUSION

More than half of patients with syncope underwent CT head with a diagnostic yield of 1.1% to 3.8%. A future large prospective study is needed to develop a robust risk tool.

The value of multidisciplinary team in syncope clinic for the effective diagnosis of complex syncope

BACKGROUND

Syncope is a perplexing challenge that often receives thorough evaluation, yet the diagnosis remains unclear. Usually, the emergency department is the first point at which patients present with syncope. However, diverse medical factors, including low diagnostic rates and inconsistent management by doctors, add to healthcare costs and delay diagnosis for syncope patients.

METHODS

Patients who had been to the emergency department at least once but were not given a clear diagnosis of syncope were recruited into our study at the time they visited syncope clinic staffed by a multidisciplinary team. Complete medical histories and clinical examinations were conducted by both experienced cardiologists and neurologists. If patients were not given a conclusive diagnosis at the syncope clinic on the basis of outpatient examinations, they were admitted for further evaluation.

RESULTS

A total of 209 consecutive patients claiming "syncope" visited the syncope clinic, yet only 167 patients were formally diagnosed with syncope. For these 167 patients, the mean age was 55.93 ± 17.40 years old, and 41.3% were male. The proportions of cardiac syncope, reflex syncope, orthostatic hypotension (OH), and syncope of uncertain etiology were 19.8%, 64.1%, 7.8%, and 8.4%, respectively. The diagnostic rate was 91.6%, and the hospitalization rate was 23.4%. Patients with reflex syncope and OH were younger than patients with cardiac syncope. Cardiac syncope tends to occur more frequently in males, while reflex syncope is more likely in females.

CONCLUSIONS

The cooperation of professional cardiologists and neurologists will play an important role in improving diagnostic rates, lowering admission rates, and reducing medical costs.

Diagnostic criteria to aid the differential diagnosis of patients presenting with transient loss of consciousness: A systematic review

BACKGROUND

Transient loss of consciousness (TLOC) is a common presentation in primary care. Over 90% of these are due to epileptic seizures (ES), syncope, or psychogenic non-epileptic seizures (PNES). Misdiagnosis rates are as high as 30%.

METHODS

Systematic review of inter-ictal clinical criteria to aid differential diagnosis of TLOC. We searched Medline, EMBASE, CINAHL and PsycInfo databases, as well as relevant grey literature depositories and citations of relevant reviews and guidelines for studies giving sensitivity and specificity of inter-ictal clinical characteristics used to differentiate between causes of TLOC. Two independent reviewers selected studies for inclusion and performed critical appraisal of included articles. We performed a narrative synthesis of included studies.

RESULTS

Of 1023 results, 16 papers were included. Two compared syncope, ES, and PNES; all others compared ES and PNES. All were at significant risk of bias in at least one domain. 6 studied patient symptoms, 6 medical and social history, 3 witness reports and 1 examination findings. No individual criterion differentiated between diagnoses with high sensitivity and specificity.

CONCLUSIONS

There is a lack of validated diagnostic criteria to help clinicians assessing patients in primary or emergency care settings to discriminate between common causes of TLOC. Performance may be improved by combining sets of criteria in a clinical decision rule, but no such rule has been validated prospectively against gold-standard diagnostic criteria.

Variation in diagnostic testing for older patients with syncope in the emergency department

BACKGROUND

Older adults presenting with syncope often undergo intensive diagnostic testing with unclear benefit. We determined the variation, frequency, yield, and costs of tests obtained to evaluate older persons with syncope.

METHODS

We conducted a prospective, multicenter observational cohort study in 11 academic emergency departments in the United States of 3686 patients aged ≥60 years presenting with syncope or presyncope. We measured the frequency, variation, yield, and costs (based on Medicare payment tables) of diagnostic tests performed at the index visit.

RESULTS

While most study rates were similar across sites, some were notably discordant (e.g., carotid ultrasound: mean 9.5%, range 1.1% to 49.3%). The most frequently-obtained diagnostic tests were initial troponin (88.6%), chest x-ray (75.1%), head CT (42.5%) and echocardiogram (35.5%). The yield or proportion of abnormal findings by diagnostic test ranged from 1.9% (electrocardiogram) to 42.0% (coronary angiography). Among the most common tests, echocardiogram had the highest proportion of abnormal results at 22.1%. Echocardiogram was an outlier in total cost at $672,648, and had a cost per abnormal test of $3129.

CONCLUSION

Variation in diagnostic testing in older patients presenting with syncope exists. The yield and cost per abnormal result for common tests obtained to evaluate syncope are also highly variable. Selecting tests based on history and examination while also prioritizing less resource intensive and higher yield tests may ensure a more informed and cost-effective approach to evaluating older patients with syncope.