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Background: Postural orthostatic tachycardia syndrome (POTS) is a chronic form of orthostatic intolerance that primarily impacts female patients of childbearing age. The role of sex differences in POTS is not well understood. We sought to identify sex differences in diagnosis, symptoms, comorbidities, and treatments in female and male patients diagnosed with POTS., Methods: A comprehensive survey was designed in partnership by Dysautonomia International (East Moriches, NY) and Vanderbilt University Medical Center (Nashville, TN). Patients were recruited through Dysautonomia International's website and social media channels. The survey was delivered online through a secure research data capture database. Responses were analyzed according to biological sex. Continuous variables are presented as median (25th percentile-75th percentile), and categorical variables are presented as number and proportion of participants., Results: A total of 8919 patients reported a physician diagnosis of POTS and were included in this analysis. The majority of respondents were female (93.7%). Female and male patients experienced misdiagnosis at similar rates (76.2% vs 74.9%, P  = 0.5) and saw a similar number of doctors before diagnosis (5 [3-8] vs 5 [3-8], P  = 0.9). Despite these similarities, diagnostic delay was longer for female, compared with male, patients (1.50 [0.25-5.25] years vs 0.92 [0.08-2.91] years, P < 0.001)., Conclusions: Despite the primarily female demographic of POTS patients, female patients experience more challenges with diagnosis than male patients. Increased awareness and recognition of POTS may help to reduce the diagnostic challenges in both female and male patients, and improve treatment and management for individuals living with this debilitating disorder., (© 2021 The Authors.)

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., (Copyright © 2021 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Aims: Vasovagal syncope (VVS) is the most common type of syncope and is usually considered a benign disorder. The potential for injury is worrisome but the likelihood is unknown. We aimed to determine the proportion of patients injured due to VVS., Methods and Results: A systematic search of studies published until August 2020 was performed in multiple medical and nursing databases. Included studies had data on the proportion of patients with injury due to VVS prior to study enrolment. Random effects methods were used. Twenty-three studies having 3593 patients met inclusion criteria. Patients were diagnosed clinically with VVS, and 82% had >2 syncopal episodes before enrolment. Tilt test was positive in 60% and 14 studies reported comorbidities (32.6% hypertensive). The weighted mean injury rate was 33.5% [95% confidence interval (CI): 27.3-40.5%]. The likelihood of injury correlated with population age (r = 0.4, P = 0.05), but not with sex, positive tilt test, or hypertension. The injury rates were 25.7% (95% CI: 19.1-32.8%) in studies with younger patients (mean age ≤50 years, n = 1803) and 43.4% (95% CI: 34.9-52.3%) in studies with older patients (P = 0.002). Nine studies reported major injuries; with a weighted mean rate of major injuries of 13.9% (95% CI: 9.5-19.8%)., Conclusion: Injuries due to syncope are frequent, occurring in 33% of patients with VVS. The risk of major injuries is substantial. Older patients are at higher risk. Clinicians should be aware of the risk of injuries when providing care and advice to patients with VVS., (Published on behalf of the European Society of Cardiology. All rights reserved. © The Author(s) 2021. For permissions, please email: journals.permissions@oup.com.)

Purpose: Postural tachycardia syndrome (POTS) and vasovagal syncope (VVS) are two disorders of orthostatic intolerance which are often misdiagnosed as the other. In each case, patients experience a reduced health-related quality of life (HRQoL) compared to healthy populations. This study was conducted to test the hypothesis that HRQoL is worse in POTS., Methods: POTS patients were recruited from the Dysautonomia International Annual Patient and Caregiver Conference. VVS patient data came from those enrolled in the Second Prevention of Syncope Trial. Participants aged ≥ 18 years (177 POTS and 72 VVS) completed the RAND 36-Item Health Survey, a generic and coherent health-related quality of life survey., Results: POTS patients reported reduced HRQoL compared to VVS patients in physical functioning (42.5 ± 1.7 vs. 76.5 ± 2.9, p < 0.001), role limitations due to physical health (11.4 ± 1.9 vs. 33.0 ± 5.0, p < 0.001), energy and fatigue (27.2 ± 1.3 vs. 50.7 ± 2.6, p < 0.001), social functioning (45.2 ± 1.8 vs. 71.2 ± 2.9, p < 0.001), pain (48.8 ± 1.9 vs. 67.7 ± 2.9, p < 0.001), and general health (31.2 ± 1.5 vs. 60.5 ± 2.6, p < 0.001) domains. Scores did not differ significantly in the role limitations due to emotional health (p = 0.052) and emotional well-being (p = 0.271) domains. Physical and general health composite scores were lower in the POTS population, while mental health composite scores were not different., Conclusion: Differences in HRQoL exist between these patient populations. POTS patients report lower scores in physical and general health domains than VVS patients, but emotional health domains do not differ significantly. Targeting physical functioning in these patients may help improve quality of life.

Syncope accounts for up to 2% of emergency department visits and results in the hospitalization of 12-86% of patients. There is often a low diagnostic yield, with up to 50% of hospitalized patients being discharged with no clear diagnosis. We will outline a structured approach to the syncope patient in the emergency department, highlighting the evidence supporting the role of clinical judgement and the initial electrocardiogram (ECG) in making the preliminary diagnosis and in safely identifying the patients at low risk of short- and long-term adverse events or admitting the patient if likely to benefit from urgent intervention. Clinical decision tools and additional testing may aid in further stratifying patients and may guide disposition. While hospital admission does not seem to offer additional mortality benefit, the efficient utilization of outpatient testing may provide similar diagnostic yield, preventing unnecessary hospitalizations.

Background: Protocols that support paramedics to assess, treat and refer low-risk syncope (fainting) may allow for ED transport of only high-risk patients. The development and uptake of such protocols is limited by a dearth of information about factors patients consider when deciding to seek EMS care following syncope., Objective: We explored decision-making processes of individuals with syncope regarding whether (or not) to call EMS after fainting as a starting point in the development of prehospital risk-stratification protocols for syncope., Methods: Twenty-five Canadian adults (aged 18-65 years) with a history of ≥ 1 syncopal episode were recruited. Individual semi-structured interviews were conducted, recorded, and transcribed. Straussian grounded theory methods were used to identify common themes and a core (overarching) category., Results: Four themes were identified: (a) previous experiences with the healthcare system (e.g., feeling dismissed), (b) individual patient factors (e.g., age, medical history), (c) attitudes and beliefs (e.g., burdening the health care system, syncope is "not serious"), and (d) contextual factors (e.g., influence of important others, symptom severity). Perceived judgement, including judgement from EMS and negative self-evaluations, was identified as the core category that influenced patients' decisions to seek care., Conclusion: We theorize that, while patients consider many factors in deciding to contact EMS for syncope, previous experiences of feeling judged and unfavorable beliefs about syncope may interfere with patients' receptiveness to traditional EMS protocols for syncope. The findings highlight potential patient needs that program developers may wish to consider in the development of prehospital protocols to improve care and satisfaction among patients with syncope.

Background: Postural orthostatic tachycardia syndrome (POTS) is a chronic form of orthostatic intolerance associated with a significant symptom burden. Compression garments are a frequently prescribed treatment, but the effectiveness of waist-high compression has not been evaluated in adults with POTS., Objectives: This study evaluated compression garments as a treatment for POTS using a head-up tilt test (HUT), and a noninflatable core and lower body compression garment., Methods: Thirty participants completed 10-min HUT with each of 4 compression conditions in a randomized crossover design. The conditions were no compression (NONE), lower leg compression (LEG), abdominal/thigh compression (ABDO), and full abdominal/leg compression (FULL). Heart rate, beat-to-beat blood pressure, and Vanderbilt Orthostatic Symptom Score ratings were measured during each HUT., Results: The compression garment reduced heart rate (NONE: 109 ± 19 beats/min; LEG: 103 ± 16 beats/min; ABDO: 97 ± 15 beats/min; FULL: 92 ± 14 beats/min; p < 0.001) and improved symptoms (p < 0.001) during HUT in a dose-dependent manner. During HUT, stroke volume and systolic blood pressure were better maintained with FULL and ABDO compression compared with LEG and NONE compression., Conclusions: Abdominal and lower body compression reduced heart rate and improved symptoms during HUT in adult patients with POTS. These effects were driven by improved stroke volume with compression. Abdominal compression alone might also provide a clinical benefit if full lower body compression is not well tolerated. (Hemodynamic Effects of Compression in POTS; NCT03484273)., Competing Interests: Author Disclosures This study was supported by funding from the Libin Cardiovascular Institute. Ms. Kate Bourne is a Vanier Scholar supported by the Canadian Institutes of Health Research. Dr. Sheldon has been a network investigator for the Cardiac Arrhythmia Network of Canada. Dr. Exner has been a network investigator for the Cardiac Arrhythmia Network of Canada. Dr. Raj has been a consultant for Lundbeck NA Ltd. and Theravance Biopharma; has been the Chair of the Data Safety and Monitoring Board for Arena Pharmaceuticals; has been a network investigator for Cardiac Arrhythmia Network of Canada; and has been a member of the Medical Advisory Board of Dysautonomia International and PoTS UK, both without financial compensation. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2021 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Background: Drivers at risk of sudden incapacitation from syncope pose a potential threat to themselves and to society. The purpose of this systematic review is to synthesize the risk of motor vehicle collisions (MVCs) for patients with a history of syncope., Methods: We systematically searched Medline (1946-2019) as well as Cinahl, Embase, Psychinfo, and the Transportation Research Information Documentation (1806-2017) for articles on MVCs and drivers with vasovagal syncope (VVS), arrhythmic syncope, or syncope not yet diagnosed (NYD). Quality ratings were assigned by team consensus., Results: Eleven studies of moderate quality were included (n = 42,972). Compared with the general populations of Canada, the United States, and the United Kingdom (0.49%-2.29% per driver-year), the prospective MVC risk was lower for VVS (0.0%-0.31% per driver-year; 3 studies; n = 782) and higher for arrhythmic syncope (1.9%-3.4% per driver-year; 2 studies; n = 730). The results were more variable for syncope NYD (0.0%-6.9% per driver-year prospectively; 6 studies; n = 41,460). Patients with syncope NYD had an almost 2-fold increased MVC risk in the largest study, although the smaller studies showed contradictory findings., Conclusions: VVS patients appear to be at very low risk for MVCs, supporting current guidelines which do not recommend driving suspension for these patients in most cases. Although the data for other forms of syncope are too limited for definitive conclusions and must be improved, arrhythmic syncope appears to be associated with nontrivial risk., (Copyright © 2020 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.)

Aims: Syncope can lead to injuries. We determined the frequency, severity, and predictors of injuries due to syncope in cohorts of syncope patients., Methods and Results: Participants were enrolled in the POST2 (fludrocortisone) and POST4 (midodrine) vasovagal syncope (VVS) randomized trials, and POST3 enrolled patients with bifascicular block and syncope. Injury was defined as minor (bruising, abrasions), moderate (lacerations), and severe (fractures, burns, joint pain), and recorded up to 1 year after enrolment. A total of 459 patients (median 39 years) were analysed. There were 710 faints occurred in 186 patients during a 1-year follow-up. Fully 56/186 (30%) of patients were injured with syncope (12% of overall group). There were 102 injuries associated with the 710 faints (14%), of which 19% were moderate or severe injuries. Neither patient age, sex, nor the presence of prodromal symptoms associated with injury-free survival. Patients with bifascicular block were more prone to injury (relative risk 1.98, P = 0.018). Patients with ≥4 faints in the prior year had more injuries than those with fewer faints (relative risk 2.97, P < 0.0001), but this was due to more frequent syncope, and not more injuries per faint. In VVS patients, pharmacological therapy significantly reduced the likelihood of an injury due to a syncopal spell (relative risk 0.64, P = 0.015). Injury severity did not associate with age, sex, or prior-year syncope frequency., Conclusion: Injuries are frequent in syncope patients, but only 4% of injuries were severe. None of age, sex, and prodromal symptoms associate with injury., (Published on behalf of the European Society of Cardiology. All rights reserved. © The Author(s) 2020. For permissions, please email: journals.permissions@oup.com.)

Study Objective: Patients with syncope are frequently admitted to the hospital, but whether this improves outcome is unknown. We tested whether hospitalization reduced mortality in patients who presented to emergency departments (EDs) with syncope., Methods: We conducted a propensity analysis of the outcomes of patients ≥18 years old presenting to EDs with a primary diagnosis of syncope in April 2004-March 2013. The model used 1:1 nearest-neighbor matching to predicted admission using age, sex, urban residence, household income, and 14 significant comorbidities from 4 administrative databases of the province of Alberta. The primary outcome was death., Results: There were 57,417 ED patients with a primary diagnosis of syncope; 8864 were admitted, and 48,553 were discharged in <24 hours. Admitted patients were older (median 76 vs 49 years), male (53% vs 45%), rural (23% vs 18%), and had lower income (median $58,599 vs $61,422); all P < 0.001. All comorbidities were higher in admitted patients (mean Charlson scores, 1.9 vs 0.7; P < 0.001). The propensity-matched hospitalized patients had higher 30-day mortality (3.5% vs 1.0%) and 1-year mortality (14.1% vs 8.6%); both P < 0.001. Mortality in all propensity quintiles was higher in the hospitalized group (all P < 0.001). The most common causes of death in 2719 patients included chronic ischemic heart disease, 14%; lung cancer, 7.1%; acute myocardial infarction, 6.9%; stroke, 3.7%; chronic obstructive pulmonary disease, 3.6%; dementia, 2.6%; and heart failure, 2.5%., Conclusions: Hospital admission did not reduce early or late mortality in patients who presented to the ED with syncope. Mortality is associated with comorbidities., Competing Interests: The authors declare no conflicts of interest., (© 2020 The Authors. JACEP Open published by Wiley Periodicals LLC on behalf of the American College of Emergency Physicians.)

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., (Copyright © 2019 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.)

Background: Vasovagal syncope (VVS) significantly reduces quality of life, yet lacks effective medical therapies. Pharmacological norepinephrine transporter (NET) inhibition increases synaptic norepinephrine reuptake, which may be able to prevent hypotension, bradycardia, and syncope., Objective: The objective of this systematic review was to evaluate the ability of 3 NET inhibitors-reboxetine, sibutramine, and atomoxetine-to prevent head-up tilt-induced vasovagal outcomes in healthy participants and patients with VVS., Methods: Relevant studies were identified from Medical Literature Analysis and Retrieval System Online, Excerpta Medica Database, Cochrane Central Register of Controlled Trials, and Cumulative Index to Nursing and Allied Health Literature without language restriction from database inception to August 2019. All randomized controlled trials comparing the benefit of a NET inhibitor vs placebo in adult populations were selected for review and meta-analysis., Results: Four studies (101 participants) met inclusion criteria. The mean study size was 25 (range 11-56) participants. NET inhibition reduced the likelihood of vasovagal reactions marked by hypotension and bradycardia in healthy participants during head-up tilt testing (relative risk 0.15; 95% confidence interval 0.04-0.52; P = .003). This relative risk reduction also occurred in patients with VVS during head-up tilt when given atomoxetine (relative risk 0.49; 95% confidence interval 0.28-0.86; P = .01). This was achieved through heart rate compensation with NET inhibition toward the end of tilt testing (106 ± 32 beats/min vs 60 ± 22 beats/min; P < .001), which in turn preserved cardiac output and mean arterial pressure (71 ± 20 mm Hg vs 43 ± 13 mm Hg; P < .001) in the absence of significantly increased systemic vascular resistance., Conclusion: NET inhibition prevents severe vasovagal reactions and syncope induced by head-up tilt testing in both healthy participants and patients with VVS. Pharmacological NET inhibition is a promising potential treatment of recurrent syncope., (Copyright © 2020 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Background: Implantable cardioverter defibrillator (ICD) acceptance and shock anxiety are issues that clinicians should address to improve quality of life among device recipients. Previous findings have indicated that younger patients experience poorer device adjustment. The purpose of this study was to examine age and ICD-specific quality-of-life outcomes in a large sample of Canadian ICD patients. We tested the hypothesis that patient age is related to device acceptance and shock anxiety in an Alberta (Canada) ICD population., Methods: The Florida Patient Acceptance Survey (FPAS) and Florida Shock Acceptance Survey (FSAS) were completed by ICD patients attending the Cardiac Implantable Electrical Device Clinics in Alberta. The population was dichotomized into those aged ≤ 65 years (younger) and those aged > 65 years (older). Sex, ICD shock history, and remote monitoring use were also examined., Results: Surveys were completed by 126 younger (53 ± 11 years; 79% male) and 216 older (74 ± 6 years; 85% male) patients. Younger, compared with older, patients had greater device-related distress ( P < 0.001) and more body-image concerns ( P < 0.001), but no differences in return to function or positive appraisal. Younger patients reported lower total device acceptance ( P  = 0.001) and greater total shock anxiety ( P < 0.001) compared with older patients., Conclusions: ICD patients aged ≤ 65 years reported poorer device acceptance and greater shock anxiety than older patients. Younger patients may require targeted interventions addressing adjustment to the ICD, and impact of the ICD on body image. Moreover, education about the relatively low probability of shocks may alleviate shock anxiety in younger patients., (© 2020 Canadian Cardiovascular Society. Published by Elsevier Inc.)

Background: Syncope is a common presentation to the emergency department (ED), yet little is known regarding patient mode of arrival., Methods: We identified patients ≥20 years old who presented to the ED with a primary diagnosis of syncope in Alberta and Ontario, Canada, between 2010 and 2016. Outcomes included 30-day in-hospital mortality, ED revisits, and rehospitalizations according to mode of arrival and discharge status. The estimated cost for ambulance use was calculated based on the provincial rates (Alberta CAD$385 and Ontario $240)., Results: A total of 271,601 syncope presentations to the ED were identified and 60.7% arrived by ambulance. A total of 76.3% (n = 125,793) of ambulance users and 87.0% of self-presenters (n = 92,845) were discharged from the ED. Regardless of mode of arrival, discharged patients were younger with fewer comorbidities. Compared with ambulance users admitted, those discharged had lower in-hospital mortality (0.2% vs 3.5%, P  < 0.001), ED revisits (4.4% vs 10.4%, P  < 0.001), and rehospitalizations (3.6% vs 10.7%, P  < 0.001). Discharged self-presenters also had significantly lower outcomes ( P < 0.001, for each outcome) compared with admitted self-presenters. The estimated cost for ambulance use among patients discharged from the ED was $33,137,735., Conclusion: A majority of syncope patients arrived to the ED by ambulance, and over 3 quarters were directly discharged home. Although discharged patients had a favourable short-term prognosis, they incurred high transportation costs. Strategies aimed at preventing unnecessary ambulance use are needed., (© 2020 Canadian Cardiovascular Society. Published by Elsevier Inc.)

Background: Risk stratification is challenging in conditions, such as chest pain, shortness of breath and syncope, which can be the manifestation of many possible underlying diseases. In these cases, decision tools are unlikely to accurately identify all the different adverse events related to the possible etiologies. Attribute matching is a prediction method that matches an individual patient to a group of previously observed patients with identical characteristics and known outcome. We used syncope as a paradigm of clinical conditions presenting with aspecific symptoms to test the attribute matching method for the prediction of the personalized risk of adverse events., Methods: We selected the 8 predictor variables common to the individual-patient dataset of 5 prospective emergency department studies enrolling 3388 syncope patients. We calculated all possible combinations and the number of patients in each combination. We compared the predictive accuracy of attribute matching and logistic regression. We then classified ten random patients according to clinical judgment and attribute matching., Results: Attribute matching provided 253 of the 384 possible combinations in the dataset. Twelve (4.7%), 35 (13.8%), 50 (19.8%) and 160 (63.2%) combinations had a match size ≥50, ≥30, ≥20 and <10 patients, respectively. The AUC for the attribute matching and the multivariate model were 0.59 and 0.74, respectively., Conclusions: Attribute matching is a promising tool for personalized and flexible risk prediction. Large databases will need to be used in future studies to test and apply the method in different conditions., Competing Interests: The authors have declared that no competing interests exist.

Background: Single-center studies have shown the high costs associated with the hospital evaluation of syncope. National cost estimates for syncope-related hospitalizations are sparse, and none exist in Canada., Methods: The Canadian Institute for Health Information Discharge Abstract Database was used to identify acute care hospitalizations with a primary diagnosis of syncope between fiscal years (FY) 2004 and 2015 in all provinces and territories (except Quebec). We used multiple linear regression to calculate the trends in prevalence of hospital admissions and generalized linear regression to estimate the costs of a hospitalization. The syncope hospitalization rate and the cost per hospitalization in Quebec were assumed to be the average of the rest of the country. The future hospitalization cost burden of syncope was projected to 2030., Results: There were 128,263 hospitalizations for a primary diagnosis of syncope over the 10-year study period, resulting in a total cost of $619.9 million (Canadian). An estimate of 41,044 syncope hospitalizations occurred in Quebec, costing $198.7 million. The total hospitalization cost of syncope in Canada was estimated at $818.5 million. The annual costs of syncope hospitalizations increased from $66.6 to $68.5 million between FY2004 and FY2015, respectively, and are projected to increase to $87.1 million in 2030., Conclusion: Hospitalization costs for syncope in Canada are high and rising. Research is needed to identify opportunities to deliver more efficient and cost-effective care., (© 2020 Canadian Cardiovascular Society. Published by Elsevier Inc.)

The current definition of postural orthostatic tachycardia syndrome (POTS) dates back to a small case series of patients with a subacute illness who presented with excessive orthostatic tachycardia and orthostatic intolerance, in the absence of another recognized disease. Conventional POTS criteria require an excessive orthostatic tachycardia in the absence of substantial orthostatic hypotension, and predominant symptoms of orthostatic intolerance, worse with upright posture and better with recumbence. POTS is a heterogeneous syndrome with likely several underlying pathophysiological processes, and not a specific disease. The primary panel for this Canadian Cardiovascular Society position statement sought to provide a contemporary update of the best evidence for the evaluation and treatment of POTS. We performed a systemic review of evidence for the evaluation of treatment of POTS using the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) methodology, and developed recommendations on the basis of the Canadian Cardiovascular Society approach to position statements. One identified problem was that numerous patients who did not meet criteria for POTS would still be given that diagnoses by providers to validate the illness even though this diagnosis is incorrect. This includes patients with postural symptoms without tachycardia, orthostatic tachycardia without symptoms, and those with orthostatic tachycardia but another overt cause for excessive tachycardia. We developed a novel nomenclature ecosystem for orthostatic intolerance syndromes to increase clarity. We also provide more clarity on how to interpret the orthostatic vital signs. These concepts will need to be prospectively assessed., (Copyright © 2019 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.)

Objectives: This study sought to determine whether sex-specific differences in management and outcomes of syncope patients exist., Background: Syncope is a common presentation to the emergency department (ED) and reason for hospital admission., Methods: Patients ≥18 years of age, presenting to the ED with a primary diagnosis of syncope in Alberta, Canada, from January 1, 2007 to December 12, 2015 were included. ED records were linked to hospital records to identify patients admitted versus discharged from the ED. Outcomes included 30-day and 1-year all-cause mortality. Multivariable mixed-effect logistic regression assessed the association between sex and outcomes., Results: Of the 63,274 ED syncope patients, 33,986 (53.7%) were women and 29,288 (46.3%) were men (p < 0.01). Compared with men, women were younger (51.6 ± 23.8 years for women vs. 55.1 ± 20.9 years for men; p < 0.001), less likely to arrive by ambulance (48.4% women vs. 51.7% men; p < 0.001), and had fewer comorbidities (67.9% women vs. 61.8% men with Charlson comorbidity score = 0; p < 0.001). Overall, 12.6% women and 16.8% men were admitted to hospital (p < 0.001). Regardless of discharge status, women had lower mortality rates (30-day admitted: 2.9% women and 4.4% men; p < 0.001; discharged: 0.2% women and 0.4% men; p < 0.001; and 1-year admitted: 12.6% women and 16.1% men; p < 0.001; discharged: 2.4% women and 3.7% men; p < 0.001). After adjusting for confounders, men were associated with 1.4-fold higher odds of death at 1 year. This was unchanged regardless of discharge status., Conclusions: Although women are more likely than men to present to the ED with syncope, they are less likely to be admitted to hospital. Mortality rates are lower for women, regardless of discharge status., (Copyright © 2020 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Syncope is a common presentation to Emergency Departments (EDs). Estimates on the frequency of visits (0.6-1.7%) and subsequent rates of hospitalizations (12-85%) vary according to country. The initial ED evaluation for syncope consists of a detailed history, physical examination and 12-lead electrocardiogram (ECG). The use of additional diagnostic testing and specialist evaluation should be based on this initial evaluation rather than an unstructured approach of broad-based testing. Risk stratification performed in the ED is important for estimating prognosis, triage decisions and to establish urgency of any further work-up. The primary approach to risk stratification focuses on identifying high- and low-risk predictors. The use of prediction tools may be used to aid in physician decision-making; however, they have not performed better than the clinical judgment of emergency room physicians. Following risk stratification, decision for hospitalization should be based on the seriousness of the underlying cause for syncope or based on high-risk features, or the severity of co-morbidities. For those deemed intermediate risk, access to specialist assessment and related testing may occur in a syncope unit in the emergency department, as an outpatient, or in a less formal care pathway and is highly dependent on the local healthcare system. For syncope patients presenting to the ED, ~0.8% die and 10.3% suffer a non-fatal severe outcome within 30 days., (Copyright © 2019 Sandhu and Sheldon.)

Only humans faint, and not all do so. Syncope tends to recur, and the predisposition to syncope can persist over many decades. Observations such as these have suggested that there may be a genetic predisposition to vasovagal syncope. It seems to have a high prevalence in some families; having a parent who faints increases the likelihood of an offspring fainting, and this is increased even further if both biological parents faint. Numerous studies have correlated a number of genotypes with positive tilt tests. However, the control subjects are usually those who faint, but have negative tilt tests, making the conclusions about association with the clinical phenotype less certain. Twin studies, highly focused genome-wide association studies, and gene duplicate studies all suggest there are sites in the genome that associate with vasovagal syncope, although the specific genes, pathways, and proteins are unknown. A recent large, candidate gene study of kindreds with high, multigenerational prevalence of the vasovagal syncope identified 3 genes that associate with vasovagal syncope. Our understanding of the genetic correlates of vasovagal syncope is in its infancy, with much to be understood., (Copyright © 2019 Sheldon and Sandhu.)

Syncope is a commonly encountered and challenging problem in medical practice. Presentations are variable, and the causal mechanism often remains elusive even after extensive (and often expensive) evaluation. Clinical practice guidelines have been developed to help guide the multidisciplinary approach necessary to diagnose and manage the broad spectrum of patients presenting with syncope. The American College of Cardiology/American Heart Association, in collaboration with the Heart Rhythm Society, published its first syncope guidelines in 2017. The European Society of Cardiology released the fourth iteration of its syncope guidelines in 2018. This review highlights the differences and congruencies between the 2 sets of recommendations, their implications for clinical practice, the remaining gaps in understanding, and areas of future research., (Copyright © 2019 American College of Cardiology Foundation. All rights reserved.)

Aims: There are few effective therapies for vasovagal syncope (VVS). Pharmacological norepinephrine transporter (NET) inhibition increases sympathetic tone and decreases tilt-induced syncope in healthy subjects. Atomoxetine is a potent and highly selective NET inhibitor. We tested the hypothesis that atomoxetine prevents tilt-induced syncope., Methods and Results: Vasovagal syncope patients were given two doses of study drug [randomized to atomoxetine 40 mg (n = 27) or matched placebo (n = 29)] 12 h apart, followed by a 60-min drug-free head-up tilt table test. Beat-to-beat heart rate (HR), blood pressure (BP), and cardiac haemodynamics were recorded using non-invasive techniques and stroke volume modelling. Patients were 35 ± 14 years (73% female) with medians of 12 lifetime and 3 prior year faints. Fewer subjects fainted with atomoxetine than with placebo [10/29 vs. 19/27; P = 0.003; risk ratio 0.49 (confidence interval 0.28-0.86)], but equal numbers of patients developed presyncope or syncope (23/29 vs. 21/27). Of patients who developed only presyncope, 87% (13/15) had received atomoxetine. Patients with syncope had lower nadir mean arterial pressure than subjects with only presyncope (39 ± 18 vs. 69 ± 18 mmHg, P < 0.0001), and this was due to lower trough HRs in subjects with syncope (67 ± 30 vs. 103 ± 32 b.p.m., P = 0.006) and insignificantly lower cardiac index (2.20 ± 1.36 vs. 2.84 ± 1.05 L/min/m2, P = 0.075). There were no significant differences in stroke volume index (32 ± 6 vs. 35 ± 5 mL/m2, P = 0.29) or systemic vascular resistance index (2156 ± 602 vs. 1790 ± 793 dynes*s/cm5*m2, P = 0.72)., Conclusion: Norepinephrine transporter inhibition significantly decreased the risk of tilt-induced syncope in VVS subjects, mainly by blunting reflex bradycardia, thereby preventing final falls in cardiac index and BP., (Published on behalf of the European Society of Cardiology. All rights reserved. © The Author(s) 2019. For permissions, please email: journals.permissions@oup.com.)

Background: Patients with postural tachycardia syndrome (POTS) experience chronic symptoms of orthostatic intolerance. There are minimal data detailing the demographics, clinical features and clinical course of this condition. This online, community-based survey highlights patients' experience with POTS. It consists of the largest sample of POTS patients reported to date., Objectives: To describe the demographics, past medical history, medications, treatments and diagnostic journey for patients living with POTS., Methods: Postural tachycardia syndrome patients completed an online, community-based, cross-sectional survey. Participants were excluded if they had not received a diagnosis of POTS from a physician. The questions focused on the patient experience and journey, rather than physiological responses., Results: The final analysis included 4835 participants. POTS predominantly affects white (93%) females (94%) of childbearing age, with approximately half developing symptoms in adolescence (mode 14 years). POTS is a chronic multisystem disorder involving a broad array of symptoms, with many patients diagnosed with comorbidities in addition to POTS. POTS patients often experience lengthy delays [median (interquartile range) 24 (6-72) months] and misdiagnosis, but the diagnostic delay is improving. POTS patients can present with a myriad of symptoms most commonly including lightheadedness (99%), tachycardia (97%), presyncope (94%), headache (94%) and difficulty concentrating (94%)., Conclusions: These data provide important insights into the background, clinical features and diagnostic journey of patients suffering from POTS. These data should serve as an essential step for moving forward with future studies aimed at early and accurate diagnoses of these patients leading to appropriate treatments for their symptoms., (© 2019 The Authors. Journal of Internal Medicine published by John Wiley & Sons Ltd on behalf of Association for Publication of The Journal of Internal Medicine.)

Background: Frequent syncope is linked to poorer health-related quality of life (HRQoL). Recurrent syncope has been observed to reduce in all groups after seeing a syncope expert and enrolling in a clinical trial. It is unknown if HRQoL improves with this reduction in syncope recurrence., Objectives: We examined the change in HRQoL over time in vasovagal syncope (VVS) patients seen by a syncope expert and enrolled in a trial. We also explored whether change differed with treatment or the frequency of fainting during follow up., Methods: The Short Form Health Survey (SF36) was completed at baseline (BL), 6 m, and 12 m post-enrollment by VVS patients in the 1st and 2nd Prevention of Syncope Trials, which were multi-centered, randomized, placebo-controlled trials of metoprolol (POST) and fludrocortisone (POST2). Differences in HRQoL at BL, 6 m, and 12 m were analyzed and compared by faints in follow-up and randomization group., Results: Complete study data were available for 143 VVS patients (40 ± 17 years, 62% F). Over 12 months, patients reported improvement in all SF36 dimensions except for bodily pain. Post hoc analyses indicated that differences first occurred between BL and 6 m for all but general health. Fainting in follow-up or drug randomization group did not diminish the improvements. The baseline syncope burden was not different whether patients' HRQoL improved or not., Conclusion: HRQoL of VVS patients improves over time after enrolling in a clinical trial, even with recurrent faints or randomization to placebo. Improvements may result from alternative factors, such as interaction with experts or patient adjustment., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Background We examined temporal trends, timing, and frequency, as well as adverse neonatal and maternal outcomes occurring in the first year postpartum among women experiencing syncope during pregnancy. Methods and Results This was a retrospective study of pregnancies between January 1, 2005, and December 31, 2014, in the province of Alberta, Canada. Of 481 930 pregnancies, 4667 had an episode of syncope. Poisson regression analysis found a 5% increase/year (rate ratio, 1.05; 95% CI, 1.04-1.06) in the age-adjusted incidence of syncope. Overall, 1506 (32.3%) of the syncope episodes first occurred in the first trimester, 2058 (44.1%) in the second trimester, and 1103 (23.6%) in the third trimester; and 8% (n=377) of pregnancies had >1 episode of syncope. Compared with women without syncope, women who experienced syncope were younger (age <25 years; 34.7% versus 20.8%; P<0.001), and primiparous (52.1% versus 42.4%; P<0.001). The rate of preterm birth was higher in pregnancies with syncope during the first trimester (18.3%), compared with the second (15.8%) and third trimesters (14.2%) and pregnancies without syncope (15.0%; P<0.01). The incidence of congenital anomalies among children born of pregnancies with multiple syncope episodes was significantly higher (4.9%) compared with children of pregnancies without syncope (2.9%; P<0.01). Within 1 year after delivery, women with syncope during pregnancy had higher rates of cardiac arrhythmias and syncope episodes than women with no syncope during pregnancy. Conclusions Pregnant women with syncope, especially when the syncopal event occurs during the first trimester, may be at a higher risk of adverse pregnancy outcomes as well as an increased incidence of cardiac arrhythmia and syncope postpartum.

Postural tachycardia syndrome (POTS) is a disorder of the autonomic nervous system with many possible causes, characterized by an unexplained increase in heartbeat without change in blood pressure upon standing. Associated cardiac and noncardiac symptoms can severely affect quality of life. Therapy, using a combined approach of diet and lifestyle changes, plus judicious use of medications if needed, can usually improve symptoms and function., (Copyright © 2019 Cleveland Clinic.)

Background: Ambulance use is a costly mode of transportation to the emergency department (ED). Syncope is a frequent presentation to the ED; however, no data exist regarding the proportion of hospitalized patients with syncope arriving by ambulance and their outcomes compared with self-presenters., Methods: The Canadian Institute for Health Information database was used to identify patients aged > 20 years hospitalized with a primary diagnosis of syncope (International Classification of Diseases 10th Revision code R55) in Canada, except Quebec, between April 2004 and March 2016. Logistic regression models (odds ratio and 95% confidence interval) were used to identify demographics, clinical factors, and province associated with ambulance use and whether ambulance use was associated with in-hospital mortality., Results: Among 108,967 syncope hospitalizations, 64% of patients arrived by ambulance, and use increased from 58.8% to 66.1% over 12 years ( P for trend < 0.01). Significant variations existed in ambulance use across provinces ( P < 0.01). Predictors associated with higher odds of ambulance use were increasing age, male sex, urban residence, residing in areas with lower annual household income, and higher comorbidity burden. In multivariable-adjusted analysis, ambulance use was associated with a 1.7-fold higher odds of in-hospital mortality., Conclusions: Approximately two-thirds of patients hospitalized for syncope presented by ambulance, and use has increased over time. Hospitalized patients in syncope who are transported by ambulance have a worse prognosis. Further research on emergency medical services' risk stratification of patients who are transported by ambulance may help to identify a low-risk population who may obviate the need for transport., (© 2019 Canadian Cardiovascular Society. Published by Elsevier Inc.)

Background: The purpose of this article is to examine the systemic circulation and left ventricular (LV) performance by alternative, nonconventional approaches: systemic vascular conductance ( G SV ) and the head-capacity relation (ie, the relation between LV pressure and cardiac output), respectively; in so doing, we aspired to present a novel and improved interpretation of integrated cardiovascular function., Methods: In 16 open-chest, anaesthetized pigs, we measured LV pressure ( P LV ), central aortic pressure ( P Ao ), and central venous pressure ( P CV ) and aortic flow ( Q Ao ). We calculated heart rate (HR), stroke volume, cardiac index (CI = cardiac output/body weight), mean P LV ( P ¯ LV ) , and the average arteriovenous pressure difference ( Δ P = P ¯ Ao - P ¯ CV ); G SV  = CI /( P ¯ Ao - P ¯ CV ). We studied the effects of changing loading conditions with the administration of phenylephrine ( Δ P ¯ Ao ≥ +25 mm Hg), isoproterenol ( ΔHR ∼+25%), sodium nitroprusside ( Δ P ¯ Ao ≥ -25 mm Hg), and proximal aortic constriction (to maximize developed P LV and minimize Q Ao )., Results: Sodium nitroprusside and isoproterenol increased G SV compared with phenylephrine and constriction. A maximum head-capacity curve was derived from pooled data using nonlinear regression on the maximum P ¯ LV values in Q Ao bins 12.5 mL/min/kg wide. The head-capacity relation and the plots of conductance were combined using CI as a common axis, which illustrated that CI is the output of the heart and the input of the circulation., Conclusions: Thus, at a given CI , G SV determines the driving pressure and, thereby, P Ao . We also demonstrated how decreases in G SV compensate for arterial hypotension by restoring the arteriovenous pressure difference and arterial pressure., (Crown Copyright © 2019 Published by Elsevier Inc. on behalf of the Canadian Cardiovascular Society.)

Background: Vasovagal syncope (VVS) patients have a reduced health-related quality of life (HRQoL). There are limited data comparing HRQoL and psychological profile in VVS patients and healthy individuals. We tested the hypothesis that VVS patients have greater impairment in both HRQoL and psychological profile compared to healthy nonfainting individuals, and that both outcome measures are negatively correlated for VVS patients., Methods: The RAND 36-Item Health Survey (RAND36), global health visual analogue scale (VAS), Hospital Anxiety and Depression Scale, Anxiety Sensitivity Index, and Positive and Negative Affect Schedule - Expanded Form were completed by healthy individuals and at baseline by VVS patients enrolled in the Second Prevention of Syncope Trial, a randomized, placebo-controlled trial of fludrocortisone for VVS., Results: Data were available on 76 VVS patients (34 ± 14 years; 68% F) and 85 healthy participants (35 ± 11 years; 80% F). Compared to healthy participants, VVS patients reported poorer HRQoL on all scales of the RAND36 and the VAS. VVS patients had significantly greater anxiety, depression, and anxiety sensitivity (each P < 0.001). VVS patients had more negative affect (P < 0.001) and less positive affect (P = 0.003) compared to healthy participants. Anxiety, depression, and anxiety sensitivity were negatively correlated with HRQoL for VVS patients, but not for healthy participants., Conclusion: In this first direct comparison, VVS patients have a significantly reduced HRQoL and more anxiety and depression compared to healthy nonfainting individuals. For VVS patients, there is a relationship between psychological distress and HRQoL, suggesting a potential benefit from more comprehensive assessment and treatment., (© 2018 Wiley Periodicals, Inc.)

A recent study found that rates of hospitalization for syncope vary across provinces; however, it is unknown whether differences in comorbidity burden and outcomes also exist. The Canadian Institute for Health Information Discharge Abstract Database was used to identify primary syncope hospitalizations (ICD-10 code R55) from 2004 to 2013 for all provinces (except Quebec). Charlson comorbidity score was calculated from comorbidities at the time of hospitalization. Outcomes were defined as in-hospital mortality, 30-day readmission for any cause, and syncope. Logistic regression models were constructed for odds ratios (ORs) and 95% confidence intervals (CIs) to estimate interprovincial differences in outcomes. The interprovincial range (IPR) for mean age was 61.1 ± 17.5 to 73.7 ± 16.3 years, and at least half were male patients. There were significant differences in comorbidity burden across provinces (P < 0.01); however, the majority of patients had a Charlson comorbidity score = 0 (IPR, 53.9%- 71.9%). In multivariable analysis, compared with Ontario, in-hospital mortality was higher for British Columbia (OR, 1.59; 95% CI, 1.22-2.06), Nova Scotia (OR, 1.67; 95% CI, 1.05-2.65), and Newfoundland (OR, 2.27; 95% CI, 1.29-4.00); 30-day readmission for any cause was higher for British Columbia (OR, 1.15; 95% CI, 1.06-1.26), Alberta (OR, 1.19; 95% CI, 1.07-1.31), Manitoba (OR, 1.36; 95% CI, 1.18-1.56), and Prince Edward Island (OR, 1.38; 95% CI, 1.0-1.89), and all outcomes were higher in Saskatchewan. There is significant interprovincial heterogeneity in comorbidity burden and outcomes for hospitalizations for syncope. Future research evaluating whether standardized practices for management of syncope reduce variability and improve healthcare utilization and costs is needed., (Copyright © 2018 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.)

Syncope is the common clinical manifestation of different diseases, and this makes it difficult to define what outcomes should be considered in prognostic studies. The aim of this study is to critically analyze the outcomes considered in syncope studies through systematic review and expert consensus. We performed a systematic review of the literature to identify prospective studies enrolling consecutive patients presenting to the Emergency Department with syncope, with data on the characteristics and incidence of short-term outcomes. Then, the strengths and weaknesses of each outcome were discussed by international syncope experts to provide practical advice to improve future selection and assessment. 31 studies met our inclusion criteria. There is a high heterogeneity in both outcome choice and incidence between the included studies. The most commonly considered 7-day outcomes are mortality, dysrhythmias, myocardial infarction, stroke, and rehospitalisation. The most commonly considered 30-day outcomes are mortality, haemorrhage requiring blood transfusion, dysrhythmias, myocardial infarction, pacemaker or implantable defibrillator implantation, stroke, pulmonary embolism, and syncope relapse. We present a critical analysis of the pros and cons of the commonly considered outcomes, and provide possible solutions to improve their choice in ED syncope studies. We also support global initiatives to promote the standardization of patient management and data collection.

Background: Atrial fibrillation (AF) and frailty are both associated with advanced age. Oral anticoagulants (OAC) effectively prevent strokes in AF patients but are underutilized in the elderly, possibly due to misperception of frailty., Objective: We performed a systematic review to determine the prevalence of frailty in patients with AF, and whether frailty was associated with reduced prescription of OAC., Methods: We systematically searched Cochrane, MEDLINE, EMBASE, and PubMed databases. Search terms combined relevant words and MeSH headings: 1) atrial fibrillation, 2) frail elderly, and 3) geriatric assessments. Studies that measured frailty using a validated instrument, and involved OAC for AF in frail and non-frail patients were eligible for inclusion. Pooled odds ratios were calculated using random-effects model., Results: Of 166 reviewed titles, only 3 studies (1204 patients) met the inclusion criteria. Two used the Reported Edmonton Frail Scale (total 509 patients), and one used the Canadian Study of Health and Aging Clinical Frailty Scale (682 patients). All 3 studies involved hospitalized patients with an average age of 85 ± 6 and 45% were male. The weighted mean prevalence of frailty in patients with atrial fibrillation was 39% (95%CI 36-42). The weighted mean rate of OAC use was 57±11%. Frailty was associated with non-prescription of OAC compared to non-frail (OR 0.49, 95% CI 0.32-0.74, I2 =45%)., Conclusion: The prevalence of frailty in hospitalized elderly patients with AF is high, and the use of OAC is low in these patients. Frail elderly are significantly less likely to receive OAC.

Objectives: This study sought to examine outcomes and costs of patients with syncope admitted and discharged from the emergency department (ED)., Background: ED visits for syncope are common, yet the impact on health care utilization is relatively unknown., Methods: A total of 51,831 consecutive patients presented to the ED with a primary diagnosis of syncope (International Classification of Diseases-9 code 780.2 and International Classification of Diseases-10 code R55) in Alberta, Canada from 2006 to 2014. Outcomes included 30-day syncope ED and hospital readmissions; 30-day and 1-year mortality; and annual inpatient, outpatient, physician, and drug costs, cumulative., Results: Of adults presenting to the ED, 6.6% were hospitalized and discharged with a primary diagnosis of syncope (Cohort 1), 8.7% were hospitalized and discharged with a primary diagnosis other than syncope (Cohort 2), and 84.7% were discharged home with a syncope diagnosis (Cohort 3). The 30-day ED revisits for syncope varied from 1.2% (Cohort 2) to 2.4% (Cohort 1) (p < 0.001), and readmission rates were <1% among cohorts. Short- and long-term mortality rates were highest for Cohort 2 and lowest for Cohort 3 (30-day mortality: Cohort 1 of 1.2%, Cohort 2 of 5.2%, Cohort 3 of 0.4%; p < 0.001) (1-year mortality: Cohort 1 of 9.2%, Cohort 2 of 17.7%, Cohort 3 of 3.0%; p < 0.001). Total cost of syncope presentations was $530.6 million (Cohort 1: $75.3 million; $29,519/patient, Cohort 2: $138.1 million; $42,042/patient, Cohort 3: $317.3 million; $9,963/patient; p<0.001)., Conclusions: Most patients with syncope presenting to the ED were discharged and had a favorable prognosis but overall costs were high compared with patients hospitalized. Further research is needed for cost-saving strategies across all cohorts., (Copyright © 2018 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Objectives: This study elucidated the temporal recurrence patterns of syncope in patients with frequent vasovagal syncope (VVS)., Background: Understanding the temporal distribution of fainting spells in syncope patients may illuminate biological processes and inform decision making., Methods: Patients from the POST 2 (Prevention of Syncope Trial 2) were included; all had VVS and fainted ≥4 times in the study year, providing ≥3 interevent intervals (IEIs). Only fainting spells separated by ≥1 day were included. IEI distributions were analyzed using Poisson modeling and cumulative sum distributions., Results: Twenty-four patients (5 males, 19 females; mean 33 years of age) had a total of 286 syncopal events and 262 IEIs, with a median 6 IEI. They resembled excluded subjects in age and sex but fainted more often in their lives (median: 57 vs. 13 fainting spells, respectively; p < 0.0001) and in the previous year (median: 23 vs. 3 fainting spells, respectively; p < 0.0001). Subjects had a median IEI duration of 8 (interquartile range: 4 to 19) days. The IEI distributions were fit well by Poisson models with a median r 2 of 0.94 (95% confidence interval: 0.91 to 0.97). The patients' Poisson rate constant frequencies were 7 to 263 fainting spells/year with a median rate of 19 fainting spells/year. The modal syncope frequency was 10 to 15 fainting spells per year. Seven patients had biexponential distributions, and many patients fainted in clusters., Conclusions: Patients with frequent VVS have fainting spells that occur randomly in time. Clusters of syncope occur, and in this population, there is a central tendency to 10 to 15 fainting spells per year. This provides a quantitative measure of frequency and predictability that may afford individualized treatment goals., (Copyright © 2017 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Background: We examined the prevalence, comorbidity burden, and outcomes of patients who presented to acute care hospitals with a primary diagnosis of syncope over a 10-year period in Canada., Methods: The Canadian Institute for Health Information Discharge Abstract Database (which contains detailed health information from all Canadian provinces and territories except Quebec) was used to identify hospitalizations of patients with a primary diagnosis of syncope (International Classification of Diseases-10th Revision code R55) 20 years of age or older in Canada from 2004 to 2014. Annual age- and sex-standardized hospital discharge rates were calculated. Logistic regression was used to examine patient factors associated with in-hospital mortality, 30-day readmission for any cause, and syncope., Results: During the 10-year study period, 98,730 hospitalizations occurred for syncope. The age- and sex-standardized hospitalization rate was 0.54 per 1000 population and decreased over time (P < 0.0001). Most patients (63%) were low-risk (Charlson comorbidity index = 0), although the proportion of patients with a Charlson comorbidity index ≥ 3 increased over time. Less than 1% of patients died in-hospital; however, among patients discharged alive, 30-day readmission rates for syncope and any cause were 1.1% and 9.0%, respectively. In-hospital mortality increased with each decade in age (odd ratio, 1.63; 95% confidence interval, 1.48-1.79), was higher in men (odds ratio, 1.37; 95% confidence interval, 1.16-1.63), and in patients with greater comorbidity (P < .0001)., Conclusions: The hospitalization rate for syncope is decreasing over time in Canada. Although the comorbidity burden of hospitalized patients is increasing, most syncope patients are low-risk. Future studies are needed to help understand how standardized diagnostic testing pathways and discharge planning might lead to more efficient and cost-effective syncope management., (Copyright © 2016 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.)

Background: Guidelines recommend that implantable loop recorders (ILRs) are used in the evaluation of people with recurrent unexplained syncope in the absence of high-risk criteria, and in high-risk patients after a negative evaluation. The aim of this systematic review was to analyze the diagnostic yield of ILRs in these patients., Methods: We performed a systematic search in order to retrieve studies enrolling adults undergoing ILR implantation for undetermined syncope. The primary outcome was the overall diagnostic yield, defined as the proportion of patients with syncope recurrence and an available ILR recording or an automatic detection of a significant arrhythmia. Secondary outcomes were the proportions of patients with the specific etiologic diagnoses on the total of subjects and the proportion of an analyzable ECG recording during symptoms. We used a random effects model for the meta-analyses., Results: Forty-nine studies, enrolling 4381 subjects, were included. The overall diagnostic yield was 43.9% (95% CI=40.2%, 47.6%; I 2 =79.8%). The proportions of subjects finally diagnosed with arrhythmic syncope, ventricular arrhythmias, supraventricular arrhythmias and bradyarrhythmias were 26.5%, 2.7%, 4.9% and 18.2%, respectively. The proportion of an analyzable ECG recording during symptoms was 89.5% (95% CI=86.1%, 92.1%; 1236 subjects; 36 studies; I 2 =44.9%). Median time to diagnosis was 134days. Heterogeneity is an important limitation to be acknowledged., Conclusions: About a half of unexplained syncope subjects implanted with an ILR were diagnosed, and around 50% of them had an arrhythmia. Life-threatening arrhythmias as well as ILR complications and death due to arrhythmic events were very rare., (Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.)