Diagnostic evaluation and management of patients with syncope

Economic evaluation of applying the Canadian Syncope Risk Score in an Australian emergency department

OBJECTIVE

To evaluate the Canadian Syncope Risk Score (CSRS) in syncope patients presenting to the ED from an economic perspective, using very-low and low-risk patients (CSRS -3 to 0) as a threshold for avoiding hospital admissions.

METHODS

A decision-analytic model, specifically a decision-tree, was developed to evaluate application of the CSRS. A hypothetical cohort of 1000 patients was modelled based on characteristics and outcome of patients enrolled in a clinical validation study performed alongside this evaluation. Several analytic based approaches were used to handle model outputs and uncertainties.

RESULTS

For a cohort of 1000 patients, applying the CSRS was associated with 169 less inpatient admissions from the ED, when compared to usual care. There was also a cost-saving of $8255 per admitted patient, when the CSRS was applied, compared to usual care. Adopting the CSRS was the optimal approach in all scenario analyses and was robust to changes in model parameters. More than three-quarters (78.6%) of all model simulations showed that applying the CSRS is a cost-saving approach to managing syncope. There was high confidence in all results, with the approach using the CSRS reducing the costs and number of syncope-related hospital admissions.

CONCLUSIONS

Compared to usual care, applying the CSRS appeared as a cost-effective strategy. This new evidence will help decision-makers choose cost-effective approaches for the management of patients presenting to the ED with syncope, as they search for efficient ways to maximise health gain from a finite budget.

Syncope, Epilepsy and Ictal Asystole: A Case Series and Narrative Review

IMPORTANCE

Syncope is a common presentation to emergency departments, and cardiac and neurological aetiologies are the predominant causes. Ictal asystole is a rare cardio-neural phenomenon seen in epilepsy syndromes whereby a seizure causes asystole (≥3 s) leading to syncope.

OBSERVATIONS

We present three cases of ictal asystole, together with a narrative review of the literature to assess the prevalence of the condition and review the pathophysiology, diagnosis and management. Our review of the literature has shown that ictal asystole is an unlikely contributor to sudden unexplained death with epilepsy (SUDEP). Pacemaker insertion may limit morbidity from trauma related to syncopal episodes but does not impact mortality.

CONCLUSIONS AND RELEVANCE

Patients with ictal asystole should be diagnosed with concurrent electroencephalogram-electrocardiograph (EEG-ECG) monitoring, have their anti-epileptic drugs optimised and be considered for epilepsy surgery if feasible. The use of longer term ECG monitoring may be used as a diagnostic aid if ictal asystole is suspected. If there are ongoing syncopal episodes with associated ictal asystole ≥6 seconds, particularly despite medical therapy, a permanent pacemaker may be considered to reduce morbidity. Current guidelines should be updated to reflect the increasing knowledge of this condition.

External validation of the Canadian Syncope Risk Score for patients presenting with undifferentiated syncope to the emergency department

OBJECTIVE

To validate the accuracy and safety of the Canadian Syncope Risk Score (CSRS) for patients presenting with syncope.

METHODS

Single centre prospective observational study in Brisbane, Australia. Adults presenting to the ED with syncope within the last 24 h were recruited after applying exclusion criteria. Study was conducted over 1 year, from March 2018 to March 2019. Thirty-day serious adverse events (SAE) were reported based on the original derivation study and standardised outcome reporting for syncope. Individual patient CSRS was calculated and correlated with 30-day SAE and disposition status from ED.

RESULTS

Two hundred and eighty-three patients were recruited to the study. Average age was 55.6 years (SD 22.7 years), 37.1% being male with a 39.9% admission rate. Thirty-day SAE occurred in seven patients (2.5%) and no recorded deaths. The CSRS performed with a sensitivity of 71.4% (95% confidence interval [CI] 30.3-94.9%), specificity 72.8% (95% CI 67.1-77.9%) for a threshold score of 1 or higher.

CONCLUSION

Syncope patients in our study were predominantly very low to low risk (72%). The prevalence of 30-day SAE was low, majority occurring following hospital discharge. Sensitivity estimates for CSRS was lower than the derivation study but lacked robustness with wide CIs because of a small sample size and number of events observed. However, the CSRS did not miss any clinically relevant outcomes in low risk patients making it potentially useful in aiding their disposition. Larger validation studies in Australia are encouraged to further test the diagnostic accuracy of the CSRS.

Diagnostic yield of pulmonary embolism testing in patients presenting to the emergency department with syncope

BACKGROUND

Syncope occurs in 1 in 4 people during their lifetime and accounts for 1% to 1.5% of emergency department (ED) visits. Most causes of syncope are benign, but syncope may be caused by life-threatening conditions including pulmonary embolism (PE) in up to 2% of cases. A recent publication reported the prevalence of PE in patients with syncope to be over 17%.

AIMS

We sought to determine the frequency and diagnostic yield of testing for PE in patients presenting to the ED with syncope in our large, integrated health care system.

METHODS

We performed a retrospective, longitudinal cohort study of patients who presented with syncope to EDs within a 21-hospital integrated health care system from 2010 to 2015 to find the frequency and diagnostic yield of testing for PE in patients with syncope at index ED visit and within 180 days afterward.

RESULTS

We screened 2 749 371 ED encounters to find 32 440 (1.2%) with syncope. Median age was 52 (interquartile range, 31-71), 57.5% were female, and 90% were Caucasian. PE was diagnosed on the index ED visit in 259 (0.8%; 95% confidence interval [CI], 0.7%-0.9%) cases. Assessment for suspected PE with D-dimer occurred in 5089 (15.7%) patients, and 2338 (7.2%) underwent computed tomography pulmonary angiography (CTPA). The yield of CTPA was 7.9%. PE was detected in 2.2% in whom a D-dimer was performed. From index visit to 180 days, 467 (1.4%; 95% CI, 1.3%-1.6%) patients were diagnosed with a PE, and 1051 (3.2%, 95% CI, 3.0%-3.4%) patients died.

CONCLUSION

Diagnostic testing for PE is frequent in patients with syncope presenting to the EDs of a large, integrated health care system. The yield of diagnostic testing is low.

Evaluating patients presenting to the emergency department after syncope: validation of the Canadian Syncope Risk Score

BACKGROUND

Syncope is a common problem but can have any of a broad range of underlying causes. Initial evaluation of the patient in the emergency department often does not identify a specific cause, and the cornerstone of management is reliable risk stratification with clinical decision rules.

OBJECTIVES

The primary objective is to validate the utility and safety of the Canadian Syncope Risk Score (CSRS) as a clinical decision rule when assessing patients who present with syncope to Australian emergency departments. Our secondary objective is to evaluate the economic benefits of diverting patients with syncope at low risk of serious adverse events from admission to hospital.

METHODS AND ANALYSIS

Prospective, observational study. Patients aged 18 years or more who present to the emergency department (ED) after syncope in the preceding 24 hours and have returned to their baseline state will be enrolled. Patients will be contacted by telephone to determine whether they have experienced any adverse events within 30 days of their initial presentation to the ED. The CSRS will be applied retrospectively to determine the relationship between whether patients were admitted to hospital or discharged home and the reporting of serious adverse events for each CSRS risk level. We will also undertake a cost-effectiveness analysis from the health care perspective.

ETHICS APPROVAL

Prince Charles Hospital Human Research Ethics Committee (reference, HREC/17/QPCH/48).

DISSEMINATION OF RESULTS

Outcomes will be disseminated by Queensland Health and the funding body via social media, presented at local and national emergency medicine conferences, and published in international emergency medicine and health economics journals.

CLINICAL TRIALS REGISTRATION

Not applicable.

Ictal asystole with isolated syncope: A case report and literature review

Ictal syncope is a rare phenomenon that occurs in association with 0.002-0.4% of seizures. In the absence of other symptoms, seizures presenting with syncope may be challenging to diagnose. We report a case of a previously healthy male who developed recurrent episodes of syncope with postictal confusion and was later diagnosed with temporal seizures. The patient was successfully treated with anti-seizure drugs and placement of a cardiac pacemaker. In a systematic review of literature, we summarize the clinical characteristics of patients with ictal asystole and isolated syncope. Seizures should be considered in patients with syncope of uncertain etiology.

Syncope in Patients with Organic Heart Disease

Patients with syncope and organic heart disease remain a small but important subset of those patients who experience transient loss of consciousness. These patients require thoughtful and complete evaluation in an attempt to better understand the mechanism of syncope and its relationship to the underlying disease, and to diagnose and treat both properly. The goal is to reduce the risk of further syncope, to improve long-term outcomes with respect to arrhythmic and total mortality, and to improve patients' quality of life.

EEG in Suspected Syncope: Do EEGs Ordered by Neurologists Give a Higher Yield?

Background:

Prior studies have shown that the electroencephalogram (EEG) is of low diagnostic yield in the evaluation of syncope but have not looked at the yield according to referring physician specialty. The goals of this study were to determine if the yield of the EEG is higher when ordered by neurologists and whether EEGs with abnormal findings resulted in any significant change in patient management.

Methods:

We retrospectively reviewed the records of the EEGs requested for a clinical diagnosis of syncope, convulsive syncope, loss of consciousness, or falls from 2003 to 2007 at our institution. We obtained further information from the medical record of patients with an abnormal EEG.

Results:

Of 517 EEGs meeting our inclusion criteria, only 57 (11.0%) were read as abnormal. No EEG was positive for epileptiform activity and only 9 (1.6%) showed potentially epileptic activity. EEGs ordered by neurologists did not have a higher yield compared to non-neurologists. Five abnormal EEGs resulted in further investigations being ordered. One patient was ultimately started on phenytoin.

Conclusions:

EEGs requested for the evaluation of patients with suspected syncope have an extremely low diagnostic yield and do not significantly alter the management of the patients, regardless of the specialty of the referring physician.

Episodic syncope caused by ventricular flutter in a tiger (Panthera tigris)

A captive, 9-yr-old castrated male tiger (Panthera tigris) from an exotic cat sanctuary and rescue facility was observed to have three collapsing episodes within a 2-wk interval prior to being examined by veterinarians. No improvement in clinical signs was noted after empiric treatment with phenobarbital. During a more complete workup for epilepsy, ventricular flutter was observed on electrocardiogram (ECG). The arrhythmia resolved with a single intravenous bolus of lidocaine. Cardiac structure and function were unremarkable on echocardiogram and cardiac troponin I levels were within normal limits for domestic felids. No significant abnormalities were noted on abdominal ultrasound. Complete blood count and biochemistry panel were unremarkable, and heartworm antigen and Blastomyces urine antigen enzyme-linked immunosorbent assays were negative. Antiarrhythmic treatment with sotalol was initiated. On follow-up ECG performed 1 mo later, no significant arrhythmias were noted, and clinical signs have completely resolved.

Routine or protocol evaluation of trauma patients with suspected syncope is unnecessary

BACKGROUND

Syncope is a commonly suspected cause of injury. Patients often undergo extensive testing without proven benefit. In this study, we investigated the utility of an inpatient syncope workup.

METHODS

A retrospective review was performed of all admissions to a Level I trauma center after fall or motor vehicle collision in patients older than 50 years and in whom syncope was suspected for the 3-year period ending December 2008. Demographics, diagnostic workup, number of abnormal results, and the frequency of subsequent interventions were recorded.

RESULTS

Two thousand one hundred seventy-one patients fulfilled study entry criteria; syncope was suspected in 302. The syncope and nonsyncope groups, respectively, were similar in age (76.9 years±12 years vs. 74.8 years±13 years) and female gender (58.3% vs. 58.4%) but differed in Injury Severity Score (7.4±5.7 vs. 9.7±7.7; p<0.01). Diagnostic workup commonly included electrocardiogram (89.4%), cardiac enzymes (88.7%), echocardiogram (78.8%), and carotid duplex or computed tomography angiography (64.9%). Significant abnormal results were uncommon: cardiac enzymes (2.9%), echocardiogram (3.8%), and carotid imaging (4.6%). Overall only 42 patients (13.9%) required further intervention, and in 29 patients (69%), the intervention was based on the initial history, physical examination, or admitting electrocardiogram.

CONCLUSION

Routine inpatient syncope workup has a low yield. Our data suggests that the diagnostic workup should be ordered based on clinical information rather than a standardized workup for all patients with suspected syncope.

Neurological aspects of syncope and orthostatic intolerance

Sudden falling with loss of consciousness from syncope and symptoms of orthostatic intolerance are common, dramatic clinical problems of diverse cause, but cerebral hypoperfusion is the ultimate mechanism in most. Cardiac, reflex, and orthostatic hypotension are important forms to consider. Syncope must be differentiated from seizures, psychiatric events, drop attacks, and other mimics. However, factors such as syncopal induced movements, ictal bradycardia, and insufficient clinical information can confound accurate diagnosis and hamper appropriate treatment. Progress in the diagnosis, treatment, and understanding of underlying mechanisms is continually advancing.

Diagnostic yield and utility of neurovascular ultrasonography in the evaluation of patients with syncope

OBJECTIVE

To determine the diagnostic utility of neurovascular ultrasonography (transcranial Doppler and carotid ultrasonography) in patients with syncope.

PATIENTS AND METHODS

We retrospectively identified consecutive patients who underwent neurovascular ultrasonography for the diagnosis of syncope or presyncope at an academic hospital in 1997 and 1998. From medical records we abstracted patient demographic and clinical information, results and consequences of testing, and follow-up data for 3 years.

RESULTS

A total of 140 patients participated in the study. The median age of the study patients was 74 years (interquartile range, 66-80 years), and 49% were male. Severe extracranial or Intracranial cerebrovascular disease was found on neurovascular ultrasonography in 20 patients (14%; 95% confidence interval [CI], 9.5%-21%). Focal neurologic signs or symptoms or carotid bruits were found in 19 (95%) of 20 patients with positive test results compared with 46 (38%) of 120 patients without severe disease (P<.001). Ultrasonography identified cerebrovascular lesions that may have contributed to the syncopal process in only 2 (1.4%) of 140 patients (95% CI, 0.39%-5.1%), but the lesions were unlikely to have been the primary cause of syncope in either patient.

CONCLUSION

In this predominantly stroke-age population, neurovascular ultrasonography had a low yield for diagnosing vascular lesions that contributed to the pathophysiology of syncope. However, in patients with focal signs or symptoms or carotid bruits, it detected incidental lesions that typically require treatment or follow-up. In patients with syncope, neurovascular ultrasonography should be reserved for this subset. The data suggest enhancements to the American College of Physicians guideline for the use of neurovascular ultrasonography in patients with syncope.

Hypersensitive carotid sinus syndrome due to neurofibromatosis-1 and manifested by repeated episodes of syncope

A 28-year-old patient with neurofibromatosis-1 presented with syncope. The exam demonstrated a mass adjacent and inferior to the right occiput that extended to the posterior lateral right-sided neck. Initial invasive and noninvasive testing was negative. Imaging of her head and neck demonstrated a large neurofibroma enveloping her right carotid sinus without vessel occlusion or evidence of malignancy. An event recorder documented asystole. A pacemaker was implanted to avoid the surgical morbidity of removing the neck mass. The patient has since been free of syncope. We believe neurofibromatosis-1 should be included in the differential of syncope.

The investigation of syncope

Patients with syncope are usually referred to either neurology or cardiology clinics, yet the facilities for detailed syncope investigation are mostly in cardiac units. The diagnosis rests principally upon the history, but investigations may be required to support the clinical diagnosis. Close collaboration between the epilepsy clinician and a cardiologist is essential for effective investigation and safe management of syncope. It is frequently misdiagnosed and often erroneously treated as epilepsy. Furthermore, it is potentially a marker of sudden death when associated with certain cardiac disorders. Here we review the main syncope types and explore diagnostic approaches.

Characteristics and admission patterns of patients presenting with syncope to U.S. emergency departments, 1992-2000

OBJECTIVES

To describe the characteristics and admission patterns of patients with syncope presenting to U.S. emergency departments (EDs).

METHODS

The ED portion of the National Hospital Ambulatory Medical Care Survey, 1992-2000, was analyzed. Nationally representative weighted estimates for incidence and admission rates were estimated and stratified by demographic variables. Presence of cardiovascular diagnoses on ED discharge was noted.

RESULTS

Of the 865 million ED visits during the nine-year study period, an estimated 6.7 million (0.77%; 95% confidence interval [95% CI] = 0.69% to 0.85%) were related to syncope. Higher incidences of ED visits for syncope were found in elder, female, and non-Hispanic patients compared with their reference groups. The overall admission rate was 32% (95% CI = 28% to 36%). Older, male, and white patients were admitted more frequently than their counterparts. Of patients older than 80 years of age, 58% (95% CI = 49% to 67%) were admitted. Associated cardiovascular International Classification of Diseases, Ninth Revision (ICD-9), codes for ischemic, structural, and arrhythmic heart disease were noted in 10% (95% CI = 8% to 13%) of patients, and 66% (95% CI = 56% to 76%) of these patients were admitted.

CONCLUSIONS

Syncope is a frequent reason for ED visits and admissions. Elders and patients with associated cardiovascular diagnoses are frequently discharged, and admission practices appear to deviate from consensus panel guidelines.

Inconsistent electrocardiographic testing for syncope in United States emergency departments

The electrocardiogram has diagnostic and prognostic value in the evaluation of syncope, and consensus guidelines suggest routine electrocardiographic testing. An analysis of a nationally representative survey suggests that electrocardiographic testing is performed inconsistently in patients presenting with syncope to United States emergency departments, even in high-risk patients, such as the elderly and hospitalized. Variation in electrocardiographic testing represents an opportunity to improve the care of patients presenting with syncope to emergency departments.

Tilt table testing in patients referred from an epilepsy clinic

OBJECTIVE

To assess the role of head up tilt testing (HUT) in diagnosing probable or possible vasovagal syncope (VVS) in patients referred from an epilepsy clinic.

METHODS

One hundred thirty two patients underwent HUT over 36 months. Complete data were available on 128 patients (52 male) aged 14-80 (mean 36.7) years. The main indication for HUT (head up tilt at 70 degrees for 45 minutes) was recurrent undiagnosed blackouts, likely to be VVS. Patients were divided, prior to knowledge of the HUT results, into probable VVS, possible VVS, or probable/possible VVS associated with definite epilepsy.

RESULTS

HUT was positive in 72 patients (56%), and led to an alternative definite diagnosis in 31 (24%). Diagnostic change was more likely in those provisionally labelled either as possible VVS (15 of 34; 44%) or as a combination of epilepsy with possible or probable VVS (12 of 19; 63%) compared to those with probable VVS (4 of 75; 5%; P<0.01).Of the 45 patients previously treated with antiepileptic medications 27 did not have epilepsy.

CONCLUSION

HUT has an important role in confirming or refuting the diagnosis of VVS in patients presenting with undiagnosed blackouts to an epilepsy clinic, and particularly so in patients with possible rather than probable VVS, and in those thought to have a combination of epilepsy and possible or probable VVS.

Syncope and orthostatic intolerance

Syncope and orthostatic intolerance remain common and significant clinical problems with many undocumented, misdiagnosed, or cryptogenic cases. Careful clinical assessment and application of advancing laboratory support can further improve diagnosis and treatment. Despite the depth of existing research into these common problems, many underlying mechanisms remain unproven.

Drug treatment of orthostatic hypotension and vasovagal syncope

Orthostatic hypotension is a common problem, estimated to occur in 5 out of every 1000 individuals and in as many as 7% to 17% of patients in an acute care setting. Moreover, orthostatic hypotension may be more prominent in elderly patients due to the increased intake of vasoactive medications and concomitant decrease in physiologic function, such as baroreceptor sensitivity, often seen with aging. Orthostatic hypotension is a fall in blood pressure on assuming an upright position. Absolute cutoffs for the drop in blood pressure are often difficult to determine because different patients exhibit varying degrees of tolerance to falls in blood pressure. Therefore, strict numerical criteria may lead to underdiagnosis and improper intervention. A thorough review of patient symptomatology combined with appropriate clinical tests should be employed to narrow the vast differential diagnosis and pinpoint the etiology. The fall in blood pressure seen in orthostatic hypotension results from the inability of the autonomic nervous system to adequately compensate for the 500 mL blood that is estimated to pool in the lower extremities on assuming an upright posture. The decrease in venous return results in a concomitant decrease in cardiac output and thus hypoperfusion of the cerebral circulation, possibly resulting in syncope or various other symptoms. A complete investigation should consider hypovolemia, removal of offending medications, primary autonomic disorders, secondary autonomic disorders and, of course, vasovagal syncope, the most common cause of syncope. Although further research is still necessary to rectify the disease process responsible for orthostatic hypotension, patients suffering from this disorder can effectively be treated through a combination of nonpharmacologic treatment, pharmacologic treatment and patient education. Agents such as fludrocortisone, midodrine and erythropoietin show promising results as therapeutic adjuncts. Treatment for recurrent vasovagal syncope includes increased salt intake, and various drug treatments, most of which are still under investigation.

Syncope: investigation and treatment

Syncope is a common condition that can be both disabling and expensive to treat. Although investigative modalities are sometimes required, a diagnosis can often be made with a good history and physical exam. Recent reports have identified specific historic features that are more suggestive of cardiac syncope as compared with vasovagal syncope and seizures. Advances in ambulatory electrocardiography (in particular the implantable loop recorder) have proven invaluable in both difficult-to-diagnose syncope, and in advancing our knowledge of its mechanisms. When clear dysrhythmias are manifest, appropriate therapies are self-evident. However, recurrent vasovagal syncope continues to be a condition that can be difficult to treat. Fortunately, there are well-conducted trials of both pharmacologic therapies (b-blockers, alpha agonists, and selective serotonin reuptake inhibitors) and nonpharmacologic treatments (orthostatic physical training and dual-chamber pacemakers) that should provide more guidance in the near future.