Are women really more affected by vasovagal syncope than men?

Women, orthostatic tolerance, and POTS: a narrative review

Young women experience orthostatic intolerance to a greater degree than men. Numerous physiological pathways could be responsible for this intolerance in both healthy and pathophysiological conditions. This review discusses sex differences in hemodynamics, ventilation, autonomic control, and cerebral blood flow. Further, we discuss these phenomena and their potential exacerbations in postural orthostatic tachycardiac syndrome (POTS). After normalization for body size women have lower stroke volume and blood volume, and while upright women have reduced ventilation, reduced venous return likely from attenuated respiratory pump and skeletal muscle pump activity, augmented parasympathetic withdrawal, attenuated neurovascular transduction of sympathetic outflow, and increased vasodilatory capacity compared to age-matched men. Women have greater middle cerebral artery blood velocity, potentially impaired cerebral dynamic autoregulation (depending on the timing), yet similar cerebrovascular reactivity to carbon dioxide exists between the sexes. Thus, we suggest that the greater incidence of orthostatic intolerance in women is primarily due to hemodynamic control and autonomic function; however, the enhanced parasympathetic withdrawal while upright could theoretically influence cerebral vasodilatory capacity and is proposed as a possibility in need of further investigation. POTS physiology is described briefly due to its increasing prevalence via post-COVID infections. We summarize some potential physiological changes in POTS including hemodynamic and ventilatory control, and we highlight that cerebral blood flow control is impaired and likely plays a role in the symptomology of POTS.

Trends in syncope testing and admissions in the USA from 2006 through 2019

INTRODUCTION

Syncope is common, with bimodal distribution through life, peaking in adolescence and in the elderly, and overall increases in incidence with age among both men and women. In this context, syncope-related visits to emergency departments (ED), hospitalizations, and testing are a significant healthcare cost burden. Ultimately, understanding the volume of testing types and settings of syncope encounters may aid in more effective healthcare utilization and high value care for this patient population.

METHODS

Data for this study were collected from the Truven Health Analytics MarketScan Database from 2006 to 2019. This database contains both commercially insured patients and those with Medicare coverage. Patients with the diagnosis of syncope were identified using International Classification of Diseases (ICD)-9 and -10 codes. We assessed the incidence of various tests for syncope evaluation and ED disposition for the study period.

RESULTS

The incidence of syncope among the study cohort rose from nine per 1000 patients to 13 per 1000 patients during the study period. The incidence of testing for syncope among multiple domains (neurologic, cardiac, blood testing) decreased in some categories, but routine testing remained prevalent. Women had a significantly lower incidence of testing in most testing domains. Discharge rate from the ED for patients presenting with syncope remained stable during the study period. However, admission rate to the hospital for those aged > 65 years increased during the study time.

CONCLUSION

Testing and admissions for syncope remain prevalent and are drivers of healthcare-associated costs. There is a clear need for further work in developing a focused approach in the evaluation of syncope patients in order to mitigate healthcare costs and improve outcomes.

Prevalence and clinical predictors of vasodepressor syncope during head up tilt test

INTRODUCTION

The aim of our study was to evaluate the prevalence and clinical predictors of vasodepressor (VD) response during head-up tilt test (HUTT) in patients with history of syncope admitted to a tertiary referral syncope unit.

MATERIAL AND METHODS

We retrospectively evaluated all consecutive patients who underwent HUTT for suspected or established reflex syncope at our institution from March 1st, 2017, to June 1st, 2023. VD response was defined when syncope occurred during hypotension along with no or slight (< 10% bpm) decrease of heart rate. Univariate and multivariate analyses were performed to test the association of VD response to HUTT with a set of clinical covariates.

RESULTS

1780 patients (40 ± 19.9 years; 49.3% male) were included; among them, 1132 (63 %) showed a positive response to HUTT and 124 (7.0%) had a VD response. The prevalence of VD response showed a peak after 69 years (11.52% vs 6.18%; P = 0.0016), mainly driven by male patients (13.7% vs 4.9%; P < 0.0001). At multivariate analysis, age (OR: 1.15; P = 0.0026) was independently associated to HUTT-induced VD syncope; in contrast, smoking (OR: 0.33: P = 0.0009) and non-classical presentation of syncope (OR: 0.55; P = 0.0029) inversely correlated with VD syncope.

CONCLUSIONS

VD response represents the less frequent responses among those induced by HUTT, accounting up to 7% of overall responses. A gender and age-related distribution has been shown. Advanced age was the only independent predictor of VD syncope; conversely, smoking and non-classical presentation of syncope reduced the probability of VD response to HUTT.

[Dizziness from an internistic perspective]

Dizziness is a common symptom with many potential causes. Medical and especially cardiac aetiologies are associated with a poor overall prognosis such that identification of the underlying cause is essential. This article gives an overview of possible causes of dizziness, how the differential diagnoses should be investigated, and describes potential therapeutic approaches to the treatment of the most important underlying conditions.

The relationship between demographic factors and syncopal symptom in pediatric vasovagal syncope

This research proposed to retrospectively analyze 20 years of clinical data and investigate the relationship between demographic factors and syncopal symptom in pediatric vasovagal syncope. A total of 2513 children, 1124 males and 1389 females, age range 3-18 years, who presented to Department of Pediatric Cardiovasology, Children's Medical Center, The Second Xiangya Hospital, Central South University with unexplained syncope or pre-syncope and were diagnosed with vasovagal syncope were retrospectively collected and divided into syncope group (n = 1262) and pre-syncope group (n = 1251). (1) Females had a 36% increased risk of syncope compared to males, a 27% increased risk of syncope for every 1-year increase in age, and a 2% decreased risk of syncope for every 1 cm increase in height. (2) A non-linear relationship between age, height, weight and syncope was observed. When age > 10.67 years, the risk of syncope increases by 45% for each 1-year increase in age; when height < 146 cm, the risk of syncope decreases by 4% for each 1 cm increase in height; when weight < 28.5 kg, the risk of syncope decreases by 10% for each 1 kg increase in weight. Demographic factors are strongly associated with syncopal symptom in pediatric vasovagal syncope and can help to predict the risk.

[Dizziness from an internistic perspective]

Dizziness is a common symptom with many potential causes. Medical and especially cardiac aetiologies are associated with a poor overall prognosis such that identification of the underlying cause is essential. This article gives an overview of possible causes of dizziness, how the differential diagnoses should be investigated, and describes potential therapeutic approaches to the treatment of the most important underlying conditions.

Effectiveness of Leg Raise and Leg Fold Maneuver to Prevent Syncope During Extraction of Teeth: A Pilot Study

Objectives The primary objective of this study is to evaluate the effectiveness of leg raise and leg fold maneuvers to prevent syncope during extraction procedures. Methods This study included 30 patients with a previous history of syncope and dental anxiety. Patients were randomly divided into two groups consisting of 15 patients each. Group I (test group) patients were educated about a few physical maneuvers, and instructions were given preoperatively about when to perform them. Group II (control group) underwent extraction conventionally. The blood pressure, saturation, pulse rate, and clinical signs and symptoms of the patients were assessed preoperatively, intraoperatively, and postoperatively. Informed consent was obtained from all the patients. Results There is a significant difference between the control and study groups in terms of the occurrence of syncope and patient comfort. This indicates that the leg raise and leg fold maneuvers reduce the occurrence of syncope during extraction. No participant in the test group experienced syncope post-treatment, while five subjects (33.3%) experienced syncope in the control group. Conclusion Physical counterpressure maneuvers are a risk-free, effective, and low-cost treatment method in patients with vasovagal syncope. Leg raise and leg fold maneuvers improved the hemodynamics of the patients.

An assessment of heart rate and blood pressure asymmetry in the diagnosis of vasovagal syncope in females

Introduction: Heart Rate Asymmetry (HRA) describes a phenomenon of differences between accelerations and decelerations in human heart rate. Methods used for HRA assessment can be further implemented in the evaluation of asymmetry in blood pressure variations (Blood Pressure Asymmetry-BPA). Methods: We have analyzed retrospectively the series of heartbeat intervals extracted from ECG and beat-to-beat blood pressure signals from 16 vasovagal patients (age: 32.1 ± 13.3; BMI: 21.6 ± 3.8; all female) and 19 healthy subjects (age: 34.6 ± 7.6; BMI: 22.1 ± 3.4; all female) who have undergone tilt test (70°). Asymmetry was evaluated with Poincaré plot-based methods for 5 min recordings from supine and tilt stages of the test. The analyzed biosignals were heart rate (RR), diastolic (dBP) and systolic Blood Pressure (sBP) and Pulse Pressure (PP). In the paper we explored the differences between healthy and vasovagal women. Results: The changes of HRA indicators between supine and tilt were observed only in the control group (Porta Index p = 0.026 and Guzik Index p = 0.005). No significant differences in beat-to-beat variability (i.e. spread of points across the line of identity in Poincaré plot-SD1) of dBP was noted between supine and tilt in the vasovagal group (p = 0.433 in comparison to p = 0.014 in healthy females). Moreover, in vasovagal patients the PP was significantly different (supine: 41.47; tilt: 39.27 mmHg) comparing to healthy subjects (supine: 35.87; tilt: 33.50 mmHg) in supine (p = 0.019) and in tilt (p = 0.014). Discussion: Analysis of HRA and BPA represents a promising method for the evaluation of cardiovascular response to orthostatic stressors, however currently it is difficult to determine a subject's underlying health condition based only on these parameters.

Exaggerated postural sway improves orthostatic cardiovascular and cerebrovascular control

Introduction

Healthy individuals with poor cardiovascular control, but who do not experience syncope (fainting), adopt an innate strategy of increased leg movement in the form of postural sway that is thought to counter orthostatic (gravitational) stress on the cardiovascular system. However, the direct effect of sway on cardiovascular hemodynamics and cerebral perfusion is unknown. If sway produces meaningful cardiovascular responses, it could be exploited clinically to prevent an imminent faint.

Methods

Twenty healthy adults were instrumented with cardiovascular (finger plethysmography, echocardiography, electrocardiogram) and cerebrovascular (transcranial Doppler) monitoring. Following supine rest, participants performed a baseline stand (BL) on a force platform, followed by three trials of exaggerated sway (anterior-posterior, AP; mediolateral, ML; square, SQ) in a randomized order.

Results

All exaggerated postural sway conditions improved systolic arterial pressure (SAP, p = 0.001) responses, while blunting orthostatic reductions in stroke volume (SV, p < 0.01) and cerebral blood flow (CBFv, p < 0.05) compared to BL. Markers of sympathetic activation (power of low-frequency oscillations in SAP, p < 0.001) and maximum transvalvular flow velocity (p < 0.001) were reduced during exaggerated sway conditions. Responses were dose-dependent, with improvements in SAP (p < 0.001), SV (p < 0.001) and CBFv (p = 0.009) all positively correlated with total sway path length. Coherence between postural movements and SAP (p < 0.001), SV (p < 0.001) and CBFv (p = 0.003) also improved during exaggerated sway.

Discussion

Exaggerated sway improves cardiovascular and cerebrovascular control and may supplement cardiovascular reflex responses to orthostatic stress. This movement provides a simple means to boost orthostatic cardiovascular control for individuals with syncope, or those with occupations that require prolonged motionless standing.

Knowledge and Awareness of Syncope Among the Population of Riyadh: A Cross-Sectional Study

Background Although syncope is a common emergency in medical settings, no research has yet evaluated the general population's awareness regarding it. This study investigated the general population's knowledge and awareness of syncope and if they could differentiate syncopal and non-syncopal causes of transient loss of consciousness (TLOC). Methodology A cross-sectional study was conducted in Riyadh through a validated, self-administered Arabic questionnaire that was distributed to the general population through social media using Google Forms (convenience sampling). Participants younger than 18 or not from Riyadh were excluded from the study. Two cardiologists validated the questionnaire, following which forward and backward translation was done. The questionnaire contained three sections. The first section included demographic data and chronic conditions. In the second section, participants were asked if they or one of their relatives had ever experienced syncope. The third section had eight scenarios assessing the participants' syncope knowledge. Subjects with ≥five correct answers were considered to be aware. Results The number of total responses was 405 participants. Regarding demographic data, 53% of the participants were female, 33% had a medical background, and 76% had a university degree (n = 214, n = 134, and n = 306, respectively). The mean age of the participants was 33.2 ± 13.3 years. Participants who were aware of syncope represented 55% (n = 221). Among the syncope cases, orthostatic syncope had the highest number of correct answers (79%, n = 319), followed by vasovagal syncope (61%, n = 246). Males performed better in cases one (p = 0.001), two (p = 0.004), and seven (p = 0.01). Conclusions The results of this study showed that most participants were considered aware of syncope. Gender, marital status, and having a medical background had a significant influence on the results.

Vasovagal syncope after blood donation in active duty military personnel of the Spanish Army

BACKGROUND

All studies of vasovagal syncope (VVS) after blood donation have been performed with civilian donors. We hypothesized that military donors have a lower incidence of VVS and a particular set of predisposing factors.

STUDY DESIGN AND METHODS

Retrospective case-control study matching every case of VVS seen from 2011 to 2019 with two controls without VVS from the same blood drive. We used the odds ratio (OR) and its 95% confidence interval (CI), estimated by multivariate logistic regression, to identify independent predictors of VVS.

RESULTS

There were 105 episodes of VVS among 65.481 whole blood donations (0.15%). VVS was more frequent among donors from military academies than from other military units (0.37% vs. 0.10%, p < .001) and in collections conducted in mobile inside setups than in mobile buses (0.23% vs. 0.06%, p < .001). In the multivariate analysis, the only independent predictors of VVS were the status of first-time donor (OR 2.6, 95% CI 1.5-4.4; p < .001) and pre-donation systolic blood pressure (SBP) < 120 mm Hg (OR 1.9, 95% CI 1.1-3.3; p = .01). Donors with both risk factors had a 5.5-fold increased risk of VVS than donors without any risk factor. Age and female sex were not predictive of VVS.

DISCUSSION

Active duty military blood donors have a lower incidence of VVS than that reported in civilian donors. First-time donors and donors with SBP < 120 mm Hg should be temporarily deferred when immediate reincorporation to hazardous or strenuous duty tasks after donation is inescapable.

Subjective versus objective tests of dizziness and vestibular function in epidemiologic screening research

BACKGROUND

Many epidemiologic studies of vestibular disorders are based on responses to questionnaires which have not been tested against objective tests of the vestibular system.

OBJECTIVE

The goal was to determine if the dizziness and balance questions used in the National Health Interview Survey (NHIS) are valid and predict performance on objective tests of the vestibular system (VNG).

METHODS

Data from 367 participants recruited from the community, aged 21.4 to 87.6 years, were collected in the Otolaryngology department at a tertiary care center. They were asked the eight NHIS questions twice, at least 30 minutes apart and were tested on VNG.

RESULTS

Question responses changed from Test 1 to Test 2 and differed between males and females. "Yes" responses did not predict abnormal VNG responses, for the total group and when the group was categorized into younger (<60 years) and older (>60 years) subjects. The sensitivity and specificity of all questions was low.

CONCLUSION

The NHIS questions provide some information about what people recall of their experiences, but they may not provide insight into the diagnostic prevalence of vestibular and balance disorders because the sensitivity and specificity are too low. Questionnaire-based epidemiologic studies should be interpreted with caution.

Gender Matters: Nonlinear Relationships Between Heart Rate Variability and Depression and Positive Affect

Vagally mediated heart rate variability (vmHRV), a measure of the parasympathetic nervous system's control over the heart, is often negatively related to maladaptive emotional outcomes. Recent work suggests that quadratic relationships involving these factors may be present; however, research has not investigated gender differences in these nonlinear functions. To address this gap, the current study tested for quadratic relationships between resting vmHRV and depression and positive affect while investigating gender differences in these relationships. Significant quadratic effects were found between resting vmHRV and reports of both depression symptoms and positive affect in women but not men. Specifically, the lowest levels of depression and the highest levels of positive affect were found at moderate vmHRV in women. These results suggest that examinations of vmHRV's nonlinear associations require the consideration of gender. Our findings are interpreted based on proposed differential neuropsychological mechanisms of vmHRV in men versus women.