Evaluation of syncope

Syncope is a transient and abrupt loss of consciousness with complete return to preexisting neurologic function. It is classified as neurally mediated (i.e., carotid sinus hypersensitivity, situational, or vasovagal), cardiac, orthostatic, or neurogenic. Older adults are more likely to have orthostatic, carotid sinus hypersensitivity, or cardiac syncope, whereas younger adults are more likely to have vasovagal syncope. Common nonsyncopal syndromes with similar presentations include seizures, metabolic and psychogenic disorders, and acute intoxication. Patients presenting with syncope (other than neurally mediated and orthostatic syncope) are at increased risk of death from any cause. Useful clinical rules to assess the short-term risk of death and the need for immediate hospitalization include the San Francisco Syncope Rule and the Risk Stratification of Syncope in the Emergency Department rule. Guidelines suggest an algorithmic approach to the evaluation of syncope that begins with the history and physical examination. All patients presenting with syncope require electrocardiography, orthostatic vital signs, and QT interval monitoring. Patients with cardiovascular disease, abnormal electrocardiography, or family history of sudden death, and those presenting with unexplained syncope should be hospitalized for further diagnostic evaluation. Patients with neurally mediated or orthostatic syncope usually require no additional testing. In cases of unexplained syncope, further testing such as echocardiography, grade exercise testing, electrocardiographic monitoring, and electrophysiologic studies may be required. Although a subset of patients will have unexplained syncope despite undergoing a comprehensive evaluation, those with multiple episodes compared with an isolated event are more likely to have a serious underlying disorder.     

Evaluation of syncope

Though relatively common, syncope is a complex presenting symptom defined by a transient loss of consciousness, usually accompanied by falling, and with spontaneous recovery. Syncope must be carefully differentiated from other conditions that may cause a loss of consciousness or falling. Syncope can be classified into four categories: reflex mediated, cardiac, orthostatic, and cerebrovascular. A cardiac cause of syncope is associated with significantly higher rates of morbidity and mortality than other causes. The evaluation of syncope begins with a careful history, physical examination, and electrocardiography. Additional testing should be based on the initial clinical evaluation. Older patients and those with underlying organic heart disease or abnormal electrocardiograms generally will need additional cardiac evaluation, which may include prolonged electrocardiographic monitoring, echocardiography, and exercise stress testing. When structural heart disease is excluded, tests for neurogenic reflex-mediated syncope, such as head-up tilt-table testing and carotid sinus massage, should be performed. The use of tests such as head computed tomography, magnetic resonance imaging, carotid and transcranial ultrasonography, and electroencephalography to detect cerebrovascular causes of syncope should be reserved for those few patients with syncope whose history suggests a neurologic event or who have focal neurologic signs or symptoms.     

Management of syncope in adults: an update

Syncope is a clinical syndrome characterized by transient loss of consciousness and postural tone that is most often due to temporary and spontaneously self-terminating global cerebral hypoperfusion. A common presenting problem to health care systems, the management of syncope imposes a considerable socioeconomic burden. Clinical guidelines, such as the European Society of Cardiology Guidelines on Management of Syncope, have helped to streamline its management. In recent years, we have witnessed intensive efforts on many fronts to improve the evaluation process and to explore therapeutic options. For this update, we summarized recent active research in the following areas: the role of the syncope management unit and risk prediction rules in providing high-quality and cost-effective evaluation in the emergency department, the implementation of structured history taking and standardized guideline-based evaluation to improve diagnostic yield, the evolving role of the implantable loop recorder as a diagnostic test for unexplained syncope and for guiding management of neurally mediated syncope, and the shift toward nonpharmacological therapies as mainstay treatment for patients with neurally mediated syncope. Syncope is a multidisciplinary problem; future efforts to address critical issues, including the publication of clinical guidelines, should adopt a multidisciplinary approach.     

Collapse query cause: the management of adult syncope in the emergency department

Syncope is a commonly encountered problem in the emergency department (ED). Its causes are many and varied, some of which are potentially life threatening. A review was carried out of relevant papers in the available literature, and this article attempts to assimilate current evidence relating to ED management. While the cause of syncope can be identified in many patients, and life threatening conditions subsequently treated, a risk stratification approach should be taken for those in whom a cause is not identified in the ED. Aspects of the history and examination that may help identify high risk patients are explored and the role of investigations to aid this stratification is discussed. Identifying a cardiac cause for syncope is a poor prognostic indicator. Patients with unexplained syncope who have significant cardiac disease should therefore be investigated thoroughly to determine the nature of the underlying heart disease and the cause of syncope, although presently there is little evidence that this improves their dismal prognosis. This risk stratification approach has led to the development of several clinical decision rules, which are discussed along with current international guidelines on syncope management. This review suggests that presently the American College of Emergency Physicians guidelines are the most useful aids specific to the management of syncope in the ED; however, the Osservatorio Epidemiologico sulla Sincope nel Lazio (OESIL) score may also be a useful ED risk stratification tool     

Understanding syncope. The pathophysiology & assessment of a challenging condition that EMS crews frequently encounter

Syncope is a transient loss of postural tone and consciousness following which, by definition, the patient has a spontaneous recovery without intervention. The differential diagnosis of syncope is broad and spans benign to life-threatening conditions. Identifying and treating serious conditions that may mimic syncope and identifying patients at high risk (cardiac syncope) are challenges that face prehospital providers. A comprehensive history and physical provide the most useful information in making these distinctions. Syncope is a symptom, not a disease; therefore, treatment must be targeted to the underlying disease process.     

Evaluation of syncope: focus on diagnosis and treatment of neurally mediated syncope

Syncope, defined as a transient loss of consciousness secondary to global cerebral hypoperfusion, is common in the general population. The single most helpful “test” in the evaluation of patients with syncope is a thoughtful history, with recent evidence that structured histories are remarkably effective in arriving at a diagnosis. In addition to the history, physical examination, and electrocardiogram, arriving at a diagnosis of syncope can involve monitoring and provocative strategies. The majority of patients with syncope have neurally mediated syncope and a favourable prognosis. The management of neurally mediated syncope continues to largely revolve around education, avoidance of triggers, reassurance, and counter-pressure maneuvers. The evidence surrounding medical therapy in vasovagal syncope is not strong to date. Pacemaker therapy is reasonable in older patients with recurrent, unpredictable syncope with pauses, but should be considered as a last resort in younger patients.     

Syncope in acute pulmonary embolism.

BACKGROUND: Syncope is a possible but little known presenting manifestation of acute pulmonary embolism (PE). The importance of syncope at the presentation of acute PE is not known. OBJECTIVES: To report the frequency and to establish the prognostic significance of syncope at the presentation of acute PE. METHODS: A retrospective review of the records of 154 consecutive patients admitted to an Internal Medicine service with acute PE. RESULTS: Fourteen patients with acute PE (9.1%) had syncope at presentation. Epidemiological and clinical characteristics (including respiratory failure, right heart failure and arterial hypotension), and hospital mortality were similar in patients with or without syncope. CONCLUSIONS: Syncope is not an uncommonly presenting manifestation of acute PE. Patients with acute PE and syncope have similar characteristics to those without syncope. Syncope does not seem to determine a poor prognosis.     

Syncope. Cost-effective patient workup

Syncope is a common problem in primary care practice that presents a diagnostic challenge. Fortunately, the initial evaluation not only identifies the cause in most patients with an identifiable cause, it also defines the prognosis for these patients. A systematic history, physical examination, and 12-lead ECG are the foundation of this evaluation and provide the most cost-effective diagnostic strategy. When signs and symptoms indicate a neurologic, cardiac, or carotid sinus problem, diagnostic procedures such as angiography, electroencephalography, cardiac catheterization, echocardiography, or carotid sinus massage should be added, but only as necessary to confirm the diagnosis. At the University of Cincinnati, we monitor patients with syncope of unknown origin with 24-hour ambulatory ECG recording and interpret the results as outlined in table 2. If not referred for cardiac or neurologic consultation, these patients are evaluated every three months for a year. This approach can minimize unnecessary testing and improve patient care.     

A novel device in evaluating syncope.

Syncope may be a manifestation of many diseases. The etiology is often difficult to determine. Much effort, time, and expense have been required to determine a diagnosis. A thorough history and physical examination are essential (Table 3). Several clinical pearls may be of help in the diagnosis of syncope: (a) the most important elements in the evaluation of syncope are a detailed history and physical examination; (b) syncope is a common problem in young healthy adults and the elderly; (c) a heavy meal is a specific cause of syncopy in the elderly (postprandial), however this etiology often goes unrecognized; (d) syncope is caused by 1 of 3 mechanisms: decreased cardiac output, systemic vascular resistance, or cerebrovascular disease; (e) reflex-mediated syndromes (vasovagal) are common causes of syncope in young adults, and orthostatic hypotension is an important cause of syncope in the elderly; and (f) the 1-year mortality of cardiac syncope (18%-33%) is significantly higher than that from non-cardiac syncope (0%-12%). A proven and useful tool has recently been advanced to aid in the evaluation of syncope. The Reveal Plus insertable loop recorder has auto activation that allows automatic capture and recording of arrhythmic events. Patient activation is an option. The recorder lasts 12 to 14 months and has proven to be a valuable and reliable cost-effective asset in our quest to evaluate syncope.     

The risk for syncope and presyncope during surgery in surgeons and nurses

Background: Surgeons and nurses are exposed to orthostatic stress. Aims: To assess the lifetime incidence of syncopal and presyncopal events during surgery in operation room staff and reveal the predicting factors. Methods and Results: The study included 317 subjects (161 F, 156 M) aged 43.9 ± 9.6; 216 surgeons and 101 instrumenters. The study included filling of an anonymous questionnaire on the syncope and presyncope history. Results: At least one syncopal event during operation was reported by 4.7% and presyncope by 14.8% of the studied population. All but one subject reported prodromal symptoms before syncope. In the medical history, syncope outside the operating room was reported by 11% of the studied group. Syncope and presyncope during operation was related to syncope in the medical history outside the operation room, respectively: odds ratio (OR) 20.2 95% confidence interval (CI): 2.0–70.5 and OR 10.8; CI: 5.0–23.4 and to presyncope in the medical history, respectively: OR 23.5; CI: 7.4–74.4 OR 8.9; CI: 3.6–11.2 (P < 0.001). Conclusions: (1) Syncope and presyncope may occur during surgery in the staff of the operating room. (2) Syncope in the operating room is usually preceded by prodromal symptoms and has vasovagal origin. (3) Both lower then expected occurrence of syncope in the operating room staff and absence of any difference between genders in this regard indicate preselection in the process of choosing profession and specialization. (4) Syncope and presyncope outside the operating room in medical history increases the risk of syncope and presyncope inside the operation room. (PACE 2011; 34:1486–1491)     

Cardiovascular causes of syncope. Identifying and controlling trigger mechanisms

Syncope usually has a cardiovascular source, so neurologic evaluation has a low diagnostic yield in these patients. Cardiac arrhythmias in persons with or without structural heart disease can produce syncope. Neurocardiogenic dysfunction that results in diminished venous return and hypercontractility is another frequent cause. Postural hypotension or left ventricular outflow obstruction may also be to blame. Careful history taking and physical examination, head-up tilt testing, echocardiography or radionuclide isotope imaging, and electrophysiologic study are often diagnostic. However, syncope remains undiagnosed in some patients, and they may require periodic reassessment. Treatment options are available for most cardiovascular disorders, among them use of pharmacologic agents; catheter, surgical, or radio-frequency modification of certain tachycardias; and permanent pacing.     

Clinical Mimics: An Emergency Medicine–Focused Review of Syncope Mimics

Background

Syncope is an event that causes a transient loss of consciousness (LOC) secondary to global cerebral hypoperfusion. The transient nature of the event can make diagnosis in the emergency department (ED) difficult, as symptoms have often resolved by time of initial presentation. The symptoms and presentation of syncope are similar to many other conditions, which can lead to difficulty in establishing a diagnosis in the ED.

Sitcom syncope: a case series and literature review of gelastic (laughter-induced) syncope

Syncope is a common complaint that is frequently evaluated without identifying a precipitating cause. Gelastic (laughter-induced) syncope is an uncommon and poorly understood condition. We describe 3 patients who experienced loss of consciousness during vigorous laughter. Each patient had an extensive medical evaluation, including a comprehensive history and physical examination, 12-lead electrocardiography, chest radiograph, routine blood analysis, polysomnography, tilt table testing, 2-dimensional transthoracic echocardiography, nuclear or echocardiographic stress testing, and 24-hour Holter monitoring. All 3 patients had an abnormal response to head-up tilt table testing, with either a significant decrease in systolic blood pressure or inappropriate heart rate response on achieving an upright position. These observations together with our review of the literature suggest that gelastic syncope may be a variant of vasodepressor syncope. Knowledge of this condition, its pathophysiology, and potential treatment options may be of value to clinicians when evaluating patients with unexplained loss of consciousness.     

Syncope: The Diagnostic Value of Head-Up Tilt Testing

To determine the usefulness of prolonged head-up tilt in the diagnosis of neurally mediated syncope, 201 patients with history of syncope of unknown cause and 102 age and gender matched control subjects underwent a 40 minute 60 degree head-up tilt test. Head-up tilt elicited syncope (i.e., was positive) in 74 of the 201 patients (37%) with a history of unexplained syncope and in only 6 of the 102 controls (6%). The specificity of the test was 100% in patients 60 years of age and older. Symptoms during tilt-induced syncope were identified by the patients as similar to those they had suffered during their spontaneous episodes. All 80 subjects who had tilt-induced syncope recovered without sequelae. The positive predictive value of a positive response to head-up tilt was 93% and the negative predictive value was 43%. The results indicate that the prolonged head-up tilt test is a very specific procedure of high diagnostic value in patients with a history of unexplained syncope. It is particularly useful in the elderly age groups who have a high incidence of syncope.     

Tilt table testing,methodology and practical insights for the clinic

Tilt table testing (TTT) has been used for decades to study short-term blood pressure (BP) and heart rate regulation during orthostatic challenges. TTT provokes vasovagal reflex in many syncope patients as a background of widespread use. Despite the availability of evidence-based practice syncope guidelines, proper application and interpretation of TTT in the day-to-day care of syncope patients remain challenging. In this review, we offer practical information on what is needed to perform TTT, how results should be interpreted including the Vasovagal Syncope International Study classification, why syncope induction on TTT is necessary in patients with unexplained syncope and on indications for TTT in syncope patient care. The minimum requirements to perform TTT are a tilt table with an appropriate tilt-down time, a continuous beat-to-beat BP monitor with at least three electrocardiogram leads and trained staff. We emphasize that TTT remains a valuable asset that adds to history building but cannot replace it, and highlight the importance of recognition when TTT is abnormal even without syncope. Acknowledgement by the patient/eyewitness of the reproducibility of the induced attack is mandatory in concluding a diagnosis. TTT may be indicated when the initial syncope evaluation does not yield a certain, highly likely, or possible diagnosis, but raises clinical suspicion of (1) reflex syncope, (2) orthostatic hypotension (OH), (3) postural orthostatic tachycardia syndrome or (4) psychogenic pseudosyncope. A therapeutic indication for TTT in the patient with a certain, highly likely or possible diagnosis of reflex syncope, may be to educate patients on prodromes. In patients with reflex syncope with OH TTT can be therapeutic to recognize hypotensive symptoms causing near-syncope to perform physical countermanoeuvres for syncope prevention (biofeedback). Detection of hypotensive susceptibility requiring therapy is of special value.     

Predictors of Positive Head-Up Tilt Test in Patients with Suspected Neurocardiogenic Syncope or Presyncope

OH, J.H., et al .: Predictors of Positive Head-Up Tilt Test in Patients with Suspected Neurocardiogenic Syncope or Presyncope. Neurocardiogenic syncope is the most common cause of syncope in patients who present in outpatient clinics. Head-up tilt test (HUT) has been widely used to diagnose neurocardiogenic syncope. However, the HUT does not always produce a positive response in patients with suspected neurocardiogenic syncope. The aim of the present study was to assess the clinical history and characteristics of patients with suspected neurocardiogenic syncope or presyncope who undertook HUT, and to identify prognostic factors of a positive HUT response. During the first phase of HUT, patients were tilted to a 70-degree angle for 30 minutes. If the first phase produced a negative response, the second phase was subsequently performed involving intravenous isoproterenol administration. Of 711 patients, 423 (59.5%) patients showed a positive HUT response. In contrast to previous studies, this study showed that the vasodepressive type (76.6%) was the most common pattern of positive response, and that the rate of positive response during the first phase was low (7.1%). By multivariate analysis, the occurrence of junctional rhythm was found to be a predictor of an impending positive response in HUT   (P < 0.001)   . The shorter time interval between the last episode and HUT was also a predictor of positive response   (P = 0.0015)   . Younger age   (P = 0.0003)   and a history of physical injury during a syncopal episode   (P = 0.019)   were found to be associated with a positive response in the first phase of HUT. (PACE 2003; 26[Pt. I]:593–598)     

Heart Rhythm During Syncope and Presyncope: Results of Implantable Loop Recorders

NIEROP, P.R., et al. : Heart Rhythm During Syncope and Presyncope: Results of Implantable Loop Recorders. Ambulatory ECG monitoring in patients with recurrent syncope is nondiagnostic in the majority of cases. Recently, an ECG implantable loop recorder (ILR) has been introduced. The ILR performs continuous ECG monitoring over a period of at least 14 months. From February 1997 to September 1999, 35 patients underwent implantation of an ILR. During a mean follow-up of  11 ± 8 months  , 24 (69%) patients had recurrent syncope or presyncope events. Four (11%) patients were not capable of activating the ILR to save the event. A symptom-rhythm correlation could be studied in 20 (83%) of 24 patients. Forty of 44 recurrences were captured by the ILR. There were 14 (40%) patients with at least one syncopal episode. An arrhythmic cause for syncope was found in eight of them (bradycardia in four and tachycardia in four). In the other six patients the heart rhythm was normal. In 17 (49%) patients with 1-year follow-up, the mean syncope event rate 12 months before ILR implantation was  4.7 ± 2.4  , whereas the mean syncope event rate 12 months after ILR implantation was  1.3 ± 0.7  (  P < 0.01  ). Resolution of symptoms was observed in 6 (17%) patients. These patients were significantly younger than patients without resolution (  50 ± 18 vs 69 ± 14 years, p < 0.01  ) and five were women. Three (9%) patients died during follow-up, all of them were noncompliant during their follow-up. In conclusion, the ILR made symptom—rhythm correlation possible in 83% of patients with recurrent syncope. Syncope recurrences decreased significantly after implantation of the device, especially in the younger patients. Noncompliant patients had a high mortality rate.     

Rational diagnostics in the management of syncope

Syncope is a non-specific symptom resulting from a variety of underlying diseases. Knowledge of the pathophysiologic basis of syncope and a structured diagnostic strategy are essential to avoid unnecessary tests and to contain costs. History, clinical examination and a 12-lead ECG can reveal the cause of syncope in up to 50 percent of patients. Close cooperation between primary care physicians, cardiologists, neurologists and psychiatrists is important for an efficient and cost-effective diagnostic work-up.     

Syncope in an elderly, institutionalised population: prevalence, incidence, and associated risk

Although syncope is common in the elderly, little is known of its epidemiology and prognosis. A retrospective analysis of syncope in 711 very old (mean age 87 years) institutionalised patients revealed a 10 year prevalence of 23 per cent and one year incidence of 7 per cent. A two-year prospective follow-up of this population revealed a yearly incidence of 6 per cent and recurrence rate of 30 per cent. Of 67 patients who developed syncope during follow-up, a cause was established in 46; 14 (21 per cent) had cardiac and 32 (48 per cent) had non-cardiac aetiologies. Twenty-one cases (31 per cent) remained unexplained. Patients who developed syncope were initially more functionally disabled (p = 0.003) and subsequently changed function more frequently (p = 0.03) than those without the development of syncope, but two year rates of hospitalisation and death were not different between the two groups. Life-table survival analysis showed no difference in the mortality of subgroups with cardiac, non-cardiac, and unknown aetiologies of syncope. Syncope is common in multiply impaired elders and is likely a manifestation of co-morbid disease rather than an independent contributor to mortality.     

动态心电图在心源性晕厥中的诊断价值

目的:探讨动态心电图(AECG)在心源性晕厥中的诊断价值.方法:对116例有晕厥病史患者行12导联AECG检测,观察在晕厥发作时心律失常的发生率及程度.结果:在检测过程中有26例发生晕厥,23例晕厥发作与严重心律失常有关,尤其与心室停搏(R-R间期)＞3.0 s及快速室性心律失常有关,有3例晕厥患者未记录到心律失常.晕厥组心律失常发生率明显高于无晕厥组(P＜0.05).结论:12导联AECG检查对心源性晕厥可作出可靠的病因诊断;检查阴性者不能完全排除心源性晕厥,应多次检查,以提高诊断阳性率.