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The clinical history is the cornerstone of diagnosing patients with transient loss of consciousness (TLOC). Reflex syncope is the most common cause of TLOC in patients across all ages. Knowledge of the variation in incidence and clinical features of reflex syncope by age and gender provides important background information to acquire an accurate diagnosis. In a cohort of 503 patients presenting with TLOC we established a final diagnosis after systematic evaluation and two years of follow-up. The occurrence of prodromal signs, symptoms, and triggers in patients with reflex syncope was analyzed by both age (< 40 yrs, 40–59 yrs and ≥ 60 years) and gender. Reflex syncope was the most frequently obtained diagnosis (60.2%) in patients of all ages presenting with TLOC. Its occurrence was higher in patients under 40 years (73.4%), than above 60 years of age (45.3%). Pallor (79.9%), dizziness (73.4%), and diaphoresis (63.0%) were the most frequently reported prodromal signs and symptoms. Most triggers and prodromal signs and symptoms were more common in patients under 40 years of age and in women. Reflex syncope is nearly twice as common in patients under 40 years of age than in patients aged 60 years or above. Typical signs and symptoms of reflex syncope are more common in younger patients and in women. Therefore, age and gender provide important diagnostic information and can help to decide whether additional testing is necessary. [ABSTRACT FROM AUTHOR]

Background: Transient loss of consciousness (TLOC) is a common clinical problem. Objective: The aim of this study was to assess the yield and accuracy of the initial evaluation, consisting of standardized history, physical examination, and ECG performed by attending physicians in patients with TLOC. Methods and Results: Five hundred and three adult patients (mean age 53 ± 19; 56% male) presenting with TLOC to the Academic Medical Center Amsterdam between February 2000 and May 2002 were included in this study. After initial evaluation, the physician made a certain, a highly likely (>80% certain), or no initial diagnosis. Initially undiagnosed patients received additional cardiological testing, additional history taking, and autonomic function tests. After 2 years of follow-up, an expert committee determined the final diagnoses. Two-year follow-up was obtained in 99% of the patients. The yield of certain diagnoses after the initial evaluation was 24%, increasing to 63% after including the highly likely diagnoses. The diagnostic accuracy of the initial certain diagnoses was 93% (95% CI 87–97%), decreasing to 88% (95% CI 84–91%) after inclusion of the initial highly likely diagnoses. Conclusion: Attending physicians can make a diagnosis based on initial evaluation in 63% of patients with TLOC, with an overall diagnostic accuracy of 88%. The use of additional testing, beyond history, physical examination, and ECG can be avoided in many patients with TLOC. [ABSTRACT FROM AUTHOR]

Introduction: Transient loss of consciousness (TLOC) is common and can be lethal. Although the patients with the most prevalent causes of TLOC have a benign prognosis, morbidity is considerable. Aim of this article, therefore, was to compare the generic quality of life (QoL) of patients presenting with TLOC with that of the general population, to compare the disease-specific QoL with that of an American referral sample, and to examine which sociodemographic and clinical factors are associated with QoL in these patients. Methods: This study was part of the fainting assessment study (FAST), which assessed diagnostic strategies for adult patients presenting with TLOC to the Academic Medical Center Amsterdam, between February 2000 and May 2002. The generic short form-36 (SF-36) health survey and the disease-specific syncope functional status questionnaire (SFSQ) were used to assess QoL. Results: Of 468 included patients, 82% completed the questionnaires. Patients with TLOC scored poorer on all scales of the SF-36 than the Dutch population, with effect sizes ranging from 0.43 to 1.11 (>0.5 = moderate effect; >0.8 = large effect). The SFSQ indicated mean impairment in 33% of the listed activities (such as driving). Female gender, higher level of comorbidity, shorter duration of complaints, having had more than one syncopal episode, and the presence of presyncopal episodes were associated with poorer QoL. Conclusion: TLOC seriously affects QoL, especially in patients with a recent onset of clinical symptoms and those suffering from both syncopal and presyncopal episodes. [ABSTRACT FROM AUTHOR]

Vasovagal syncope (VVS) is a consistent, but infrequent (0.1%-0.3%) complication of volunteer, whole blood donation. Given the large number of blood donations, a significant number of donors is involved. Syncope occasionally leads to injury. Recent rigorous data collection and analysis have led to the association of a small number of donor and donation factors with the risk of syncope. An analysis of the time course of syncope reactions among approximately 500,000 whole blood donors suggests that there are three distinct periods of risk for vasovagal reactions before, during, and after phlebotomy. This review examines the physiologic mechanisms that contribute to these periods of increased risk including the direct effects of removal of approximately 500 mL of whole blood, the psychological stress of instrumentation and giving blood (i.e., fear of needles, pain, and the sight of blood), and the orthostatic effects superimposed on a hypovolemic state after the donation. Specifically, we describe interventions that have been useful in controlling VVS in patients with fainting syndromes and we examine the potential of these interventions in the blood donation context, based on the physiologic principles involved. Finally, we propose an intervention (dietary replacement of salt lost with blood donation) that has not been applied in transfusion medicine previously but which has the potential to reduce risk. [ABSTRACT FROM AUTHOR]

Vasoconstrictor capacity, skeletal muscle tone, and renal sodium retention are involved in the pathogenesis of fainting. As muscle contractility and ion transport are highly energy-demanding processes, we hypothesized that a low activity of the energy-generating enzyme creatine kinase (CK) is associated with a higher risk of fainting. The aim of this observational study was to explore the association of vasovagal syncope with low CK. A random sample of 1,000 subjects aged 34–60 years was drawn from the general population, with 442 subjects eventually included in the study. Data on fainting history were collected with the investigators blinded to participants’ CK level. We prepared this report according to the “Strengthening the Reporting of Observational Studies in Epidemiology” (STROBE) statement. The main outcome was the lifetime cumulative incidence of vasovagal syncope in subjects with low versus high-normal serum CK after a 3 days rest. The proportion of fainters within the high CK group was 29 out of 130 (22%) versus 121 out of 312 (39%) in the low CK group; a 73% greater occurrence of fainting with low CK ( P = 0.0005). This finding was consistent across recurrent fainters, and in men and women. Low CK is associated with a 73% higher incidence of fainting in a random population sample. The association is biologically plausible, as CK enhances cardiovascular and skeletal muscle contractility and salt retention. The presented data suggest that low CK activity is a potential new risk factor for vasovagal syncope. [ABSTRACT FROM AUTHOR]

Introduction: There are limited and conflicting data on the lifetime cumulative incidence of syncope in the general population. The aim of our study was to determine the lifetime cumulative incidence and triggers of syncope in the general population. Methods: Questions about syncope were added to a cross-sectional survey on cardiovascular risk factors carried out between 2001 and 2003 in 549 native Dutch respondents, aged 35–60 years. Results: The lifetime cumulative incidence of syncope in our study population was 35% (95% confidence interval 31–39%). Syncope occurred more often in women than in men (41% vs 28%; P = 0.003). A peak in the incidence of syncope occurred around the age of 15 years in both men and women. The median number of episodes in persons with syncope was 2 (Inter Quartile Range 1–5). The top five most frequently mentioned triggers of syncope included warm environment, pain, insufficient food intake, seeing blood/venipuncture, and emotion. Conclusion: In conclusion, our study shows that the lifetime cumulative incidence of syncope in the general population is high. Females experience syncope more often than males. The majority of the syncope triggers were related to conditions that affect orthostatic blood pressure regulation and vasomotor responses. [ABSTRACT FROM AUTHOR]

Background:We aimed to develop and test a literature-based model for symptoms that associate with cardiac causes of syncope. Methods and Results:Seven studies (the derivation sample) reporting ≥2 predictors of cardiac syncope were identified (4 Italian, 1 Swiss, 1 Canadian, and 1 from the United States). From these, 10 criteria were identified as diagnostic predictors. The conditional probability of each predictor was calculated by summation of the reported frequencies. A model of conditional probabilities and a priori probabilities of cardiac syncope was constructed. The model was tested in four datasets of patients with syncope (the test sample) from Calgary (n=670; 21% had cardiac syncope), Amsterdam (n=503; 9%), Milan (n=689; 5%) and Rochester (3877; 11%). In the derivation sample ten variables were significantly associated with cardiac syncope: age, gender, structural heart disease, low number of spells, brief or absent prodrome, supine syncope, effort syncope, and absence of nausea, diaphoresis and blurred vision. Fitting the test datasets to the full model gave C-statistics of 0.87 (Calgary), 0.84 (Amsterdam), 0.72 (Milan) and 0.71 (Rochester). Model sensitivity and specificity were 92% and 68% for Calgary, 86% and 67% for Amsterdam, 76% and 59% for Milan, and 73% and 52% for Rochester. A model with 5 variables (age, gender, structural heart disease, low number of spells, and lack of prodromal symptoms) was as accurate as the total set. Conclusion:A simple literature-based Bayesian model of historical criteria can distinguish patients with cardiac syncope from other patients with syncope with moderate accuracy. [ABSTRACT FROM AUTHOR]