Vasovagal Research Articles

Predictive value of Tpeak-Tend interval of supine and orthostatic electrocardiogram in the diagnosis between psychogenic pseudosyncope and vasovagal syncope in children

Predictive value of Tpeak-Tend interval of supine and orthostatic electrocardiogram in the diagnosis between psychogenic pseudosyncope and vasovagal syncope in children

Comparative study of the therapeutic effects of radiofrequency ablation of ganglionated plexi guided by high-frequency stimulation and anatomical localization methods in the treatment of vagal syncope in young people.

To investigate the differences in safety and efficacy between high-frequency stimulation (HFS) and anatomically guided endocardial catheter ablation (AA) of the ganglionated plexi (GPs) for treating vasovagal syncope (VVS) in individuals engaged in high-intensity physical training. Forty-five patients (age 22.5 ± 4.4 years) undergoing high-intensity physical training were included from January 2020 to January 2023 at our hospital. Patients underwent GP ablation for recurrent syncope. Comprehensive evaluations, including head MRI, cardiac ultrasound, electrocardiogram (ECG), ambulatory ECG (Holter), ambulatory blood pressure monitoring, plate motion tests, and head-up tilt tests (HUT), were conducted to exclude other systemic disorders causing syncope. HFS and AA-guided GP ablation were performed on 10 and 35 patients, respectively, all of whom tested positive for HUT. Differences between the two groups were compared regarding ablation sites, ablation time, safety, and effectiveness. The ablation time was significantly shorter in the AA group compared to the HFS group (P < 0.001). The number of GPs selected for ablation using the AA method was reduced (P < 0.001). All patients in the HFS group experienced palpitations and discomfort, whereas only 31.43% of patients in the AA group reported these symptoms (P = 0.001). Fentanyl analgesia was administered in both groups, and no significant complications arose from the ablation. The longest follow-up duration was 52 months, while the shortest was 15 months. One case of pre-syncope occurred in the HFS group 8 months post-ablation, and one case of pre-syncope and two cases of syncope occurred in the AA group at 1 and 3 months post-ablation, respectively. There were no statistically significant differences in heart rate variability (HRV) and cardiac deceleration capacity (DC) between the two groups after ablation (P > 0.05). Two cases in the AA group still exhibited type II second-degree atrioventricular block during sleep. Both groups of patients were able to complete high-intensity physical training and showed significant symptom improvement post-ablation. Young individuals with VVS engaged in high-intensity physical training can benefit from GP ablation using both HFS and AA methods. The AA method requires relatively simple equipment, shorter procedure time, and results in less discomfort during the ablation.

Abstract 4126987: A Case of Recurrent Neurocardiogenic Syncope in a COVID-19 Patient

Background: COVID-19 infection has been associated with a broad range of clinical manifestations. There are very few reported cases of COVID-19 patients presenting with syncope as an initial symptom. We present an extraordinary case of recurrent neurocardiogenic syncope in a COVID-19 patient. Case: A 66-year-old male presented after experiencing two episodes of syncope. He denied any prodromal or anginal symptoms. His medications included propranolol 10 mg twice daily for essential tremors. He had no family history of unexplained syncope or sudden cardiac death. He was hemodynamically stable and had one episode of fever at 102°F. Telemetry recording showed vagal-mediated sinus arrest and pauses without escape. Blood work showed normal cell counts, electrolytes, thyroid-stimulating hormone, and erythrocyte sedimentation rate, with a slightly elevated C-reactive protein of 22.2 mg/L. He tested positive for COVID-19 and had negative Lyme and Ehrlichia serologies. Decision Making: Due to symptomatic long sinus pauses, propranolol was discontinued, and he received a temporary pacemaker set at 50 beats per minute (bpm). He had another syncopal episode while being paced at 50 bpm, suggesting a neurocardiogenic mechanism, so the pacing rate was increased to 70 bpm. An echocardiogram showed a normal ejection fraction without any significant valvular disease. The syncope was determined to be vasovagal due to autonomic dysfunction in the setting of COVID-19. After 72 hours without further syncope, the temporary pacemaker was removed, and he was discharged home with an implantable loop recorder (ILR). A one-month follow-up showed no syncope, and ILR interrogation showed no bradycardia or pauses. Conclusion: Neurocardiogenic syncope with prolonged asystole and sinus pauses is an uncommon presentation of COVID-19 infection. The clinical course of autonomic dysfunction following COVID-19 is not very clear, and monitoring with an ILR is reasonable before considering permanent pacemaker implantation.

Isolated very low QRS voltage in at least one frontal lead is associated with vasovagal syncope in children.

To assess whether isolated very low QRS voltage of ≤0.3 mV in the frontal leads might be a marker for diagnosing paediatric vasovagal syncope and the risk of recurrence. We included 118 children with vasovagal syncope, comprising 70 males and 48 females in our retrospective analysis. All patients underwent head-up tilt test and supine 12-lead electrocardiography. Furthermore, the QRS voltage was measured from each one of the 12 leads on basal electrocardiography. Patients were followed up for 6-24 months (average, 16 months). Eighty-six patients (73%) patients displayed isolated very low QRS voltage in frontal leads. Furthermore, the patients were classified into two groups based on the presence or absence of isolated very low QRS voltage. Enhanced syncopic spells over the past 6 months, and the positive rates of head-up tilt test were observed in patients having isolated very low QRS voltage in the frontal leads than those without isolated very low QRS voltage (p < 0.05). The single factor and time-to-event analyses also showed an increased syncope recurrence rate in patients with isolated very low QRS voltage in frontal leads when compared with those without isolated very low QRS voltage (p < 0.01). Isolated very low QRS voltage in frontal leads is correlated with the positive response of the head-up tilt test in children who experience syncope and its recurrence post-treatment. Hence, isolated very low QRS voltage in frontal leads might become a novel diagnostic indicator and a risk factor for syncope recurrence in children with vasovagal syncope.

Effect of age on clinical impact and mid-term denervation in patients undergoing cardioneuroablation.

Cardioneuroablation (CNA) represents a promising therapy for recurrent vasovagal syncope (VVS), extrinsically driven atrioventricular block (AVB) and sinus node dysfunction (SND). However, effectiveness in patients aged 50 and above is not well-established. In this prospective study of patients referred for CNA, we compared syncope and pacemaker implantation free survival, heart rate (HR) variability (HRV) and quality of life between two age groups: group A (< 50 years) and B (≥ 50 years). A total of 50 patients were included (17 Group A and 33 Group B). The etiologies comprised VVS (56%), AVB (22%), and SND (22%). After a median follow-up of 17.0 (12.5-26.0) months, there were no differences of the combined endpoint of syncope or pacemaker implantation free-survival between groups (29.4.% vs. 21.2%; p-log-rank = 0.736). 84% of the entire cohort remained free from syncope, with a better but not significant syncope free survival in the older group (23.5% vs. 12.1%; p-log rank = 0.486). There were no differences in pacemaker implantation rate (A 5.9% vs. B 17.6%; p log-rank = 0.658). Notably, older patients had lower HR values post-procedure compared to younger patients (68.9 ± 13.3 vs. 80.4 ± 16.3bpm; p = 0.012). Both groups exhibited a decrease in HRV parameters and an improvement in quality of life. In conclusion, CNA has comparable clinical benefits for patients aged 50 and above in terms of syncope or pacemaker implantation free survival and HRV reduction when compared to younger patients.

Refractory Vasovagal Syncope Despite Tilt Training: Should Paroxetine be Included in the Treatment?

Refractory Vasovagal Syncope Despite Tilt Training: Should Paroxetine be Included in the Treatment?

Diagnostic and therapeutic challenges in vasovagal syncope - a case report and literature review

Diagnostic and therapeutic challenges in vasovagal syncope - a case report and literature review

Heart Rate Variability in Basketball: The Golden Nugget of Holistic Adaptation?

The main aim of this narrative review is to assess the existing body of scientific literature on heart rate variability (HRV) in relation to basketball, focusing on its use as a measure of internal load and vagal nerve responses. Monitoring HRV offers insights into the autonomic function and training-induced adaptations of basketball players. Various HRV measurement protocols, ranging from short-term to longer durations, can be conducted in different positions and conditions, such as rest, training, and sleep, to determine this key metric. Consistency and individualization in measurement protocols, responding to the athlete’s specific characteristics, is crucial for reliable HRV data and their interpretation. Studies on HRV in basketball have explored psychological adaptation, training effects, individual differences, recovery, and sleep quality. Biofeedback techniques show positive effects on HRV and anxiety reduction, potentially enhancing performance and stress management. The scientific literature on HRV in basketball could benefit from studies involving longer monitoring periods to identify significant trends and results related to training and recovery. Longitudinal HRV monitoring in teams with intense travel schedules could reveal the impact on athletes of all levels and ages, and, in this regard, individualized interpretation, considering the subjective recovery and fitness levels of athletes, is recommended to optimize training programs and performance. HRV provides insights into training and competitive loads, aiding in determining exercise intensities and training status. Additionally, HRV is linked to recovery and sleep quality, offering valuable information for optimizing player performance and well-being. Overall, HRV is a reliable tool for adjusting training programs to meet the specific needs of basketball players.

Complications associated with pulsed field ablation versus radiofrequency catheter ablation of atrial fibrillation

BackgroundThe first commercial systems for pulsed field ablation(PFA) were recently approved by the Food and Drug Administration(FDA), but their safety profile in nationwide practice remains underexplored. ObjectiveThis study aimed to describe reported adverse events with PFA systems after their market release and to compare the relative proportion of complications associated with PFA versus radiofrequency(RF) ablation catheters. MethodsWe conducted a search of the Manufacturer and User Facility Device Experience database for adverse event reports involving FDA-approved PFA and RF catheters between January 1, 2024, to July 31, 2024. ResultsA total of 1,237 reports detailing clinical complications (N=156 for PFA and N=315 for RF) or catheter malfunctions (N=336 for PFA and N=430 for RF) were analyzed. The most common adverse events reported for PFA were pericardial effusion, vasovagal response, and hemolysis, and for RFA were pericardial effusion, ischemic stroke, and esophageal damage. The proportion of reported adverse events that were deaths was lower among PFA compared to RF (2.6% vs. 8.9%, P=0.010). Hemolysis (9.0% vs. 0%), coronary events (5.8% vs. 0.6%), and vasovagal responses (14.1% vs. 0%) were reported more frequently after PFA (all P<0.001). In contrast, esophageal damage (0% vs. 4.1%, P<0.001) and pulmonary vein stenosis (0% vs. 1.9%, P=0.184) were not reported with PFA, only with RF. Regarding catheter malfunctions, mechanical problems were reported in greater proportion after PFA compared with RF (87.2% vs. 17.2%, P<0.001). ConclusionThe reported complications associated with PFA and RF ablation differ significantly. Close attention to PFA-specific complications is essential for ensuring the safe use of PFA and for mitigating risk.

Unraveling autonomic cardiovascular control complexity during orthostatic stress: Insights from a mathematical model

Understanding cardiovascular control mediated by the autonomic system remains challenging due to its inherent complexity. Consequently, syndromes such as orthostatic intolerance continue to evoke debates regarding the underlying pathophysiological mechanisms. This study develops a comprehensive mathematical model simulating the control of the sympathetic branch of the cardiovascular system in individuals with normal and abnormal responses to the head-up-tilt test. We recruited four young women: one control, one with vasovagal syncope, one with orthostatic hypertension, and one with orthostatic hypotension, exposing them to an orthostatic head-up tilt test (HUTT) employing non-invasive methods to measure electrocardiography and continuous blood pressure.Our work encompasses a compartmental model formulated using a system of ordinary differential equations. Using heart rate as input, we predict blood pressure, flow, and volume in compartments representing the veins, arteries, heart, and the sympathetic branch of the baroreflex control system. The latter is modulated by high- and low-pressure baroreceptor afferents activated by changes in blood pressure induced by the HUTT. Sensitivity analysis, parameter subset selection, and optimization are employed to estimate patient-specific parameters associated with autonomic performance. The model has seven sensitive and identifiable parameters with significant physiological relevance that can serve as biomarkers for patient classification.Results show that the model can reproduce a spectrum of blood pressure responses successfully, fitting the trajectory displayed by the experimental data. The controller exhibits behavior that emulates the operation of the sympathetic system. These encouraging findings underscore the potential of computational methods in evaluating pathologies associated with autonomic nervous system control, warranting further exploration and novel approaches.

Survey of Practice Patterns in the Use of Superior Laryngeal Nerve Blocks.

Superior laryngeal nerve (SLN) injection is performed for a variety of upper aerodigestive tract-related indications. Existing literature examines the efficacy of SLN injection for specific indications. However, there is a paucity of insight into overall practice patterns and a lack of standardization, particularly with regards to medication and dosing, treatment time frame, and circumstances. The goal of this study is to elucidate the practice patterns of SLN injection and allow for broader understanding of its utilization. This is a descriptive study of results from an electronic survey disseminated via email to US-based and international otolaryngologists and laryngologists. 80 responses were collected. 53.8% responders endorsed utilizing SLN injection in their practice, including 39/43 laryngologists (90.7%). Responders perform SLN injection for an array of indications, using a variety of anesthetic and steroid combinations and dosages. The most used steroid is triamcinolone (81.4%). The most used anesthetic is lidocaine (53.5%). 43% of respondents endorse willingness to perform bilateral injections simultaneously. Follow-up after initial injection is highly inconsistent, as are time intervals between injections and number of injections performed. With regards to side effects and complications discussed prior to the procedure, 95% counseled patients on pain/discomfort while roughly half of responders discussed bleeding/hematoma, aspiration risk, vasovagal response, and/or globus sensation, respectively. This is the first known study investigating the practice patterns of SLN injection. The substantial variability of responses reflects a lack of standardization of this procedure despite its widespread use. Further study is needed to optimize protocols. Levels 5 and 6 Laryngoscope, 2024.

Atrial rates during treated ventricular tachycardia in patients with implantable cardioverter defibrillators: clinical implications of a vagal sinus node response

Abstract Introduction Autonomic tone plays an important role in the genesis and sustenance of ventricular tachycardia (VT). Whilst sympathetic hyperactivity is an established driver of ventricular arrhythmias, sinus node response during VT varies broadly between patients, and can be paradoxical. Purpose We hypothesized that device-detected changes in sinus node rate could be an important surrogate of the autonomic response to VT, and may exert significant – and potentially modifiable – haemodynamic consequences independent of ventricular activity. Methods Device electrograms were analysed from consecutive patients with dual chamber implantable cardioverter defibrillators (ICDs) requiring anti-tachycardia pacing (ATP) or defibrillation for sustained monomorphic VT. Atrial rates were measured before VT onset (‘baseline’) and again at the point of detection by the device. Sinus node response was characterized as ‘stable’ (atrial rate remained within 10% of baseline), ‘sympathetic’ (atrial rate increased &amp;gt;10%) or ‘vagal’ (atrial rate decreased &amp;gt;10%). Patients who did not maintain ventriculoatrial dissociation or who presented in atrial tachyarrhythmia were excluded. Symptoms and electrical response to ICD therapies were recorded. Results 172 treated episodes of VT were included from 97 patients (median age: 69 years, 65% male, 31% ischaemic cardiomyopathy, median ventricular rate: 205bpm, median ejection fraction: 30%). Sinus node response was stable in 55%, sympathetic in 24% and vagal in 21%. A vagal response was associated with ATP-refractory VT (OR: 2.2 (1.1-4.8) p=0.03) and, when adjusting for ventricular rate, was independently associated with symptoms of presyncope or syncope (adjusted OR: 6 (2.7-13.7), p&amp;lt;0.0001). Conclusions This preliminary analysis suggests that a vagal sinus node response during VT is associated with adverse outcomes in ICD patients. Vagolytic therapy has recently been demonstrated to improve haemodynamic tolerance during VT ablation; whether supportive atrial pacing during VT could mitigate symptoms and potentiate arrhythmia termination in ICD patients warrants further exploration. Figure 1: Change in sinus node rate during sustained monomorphic ventricular tachycardia in patients with dual chamber ICDs, stratified by the occurrence of presyncopal symptoms or syncopeFigure 1

Machine learning model using heart rate variability for the prediction of vasovagal syncope

Abstract Background and Aims: Vasovagal syncope (VVS) is a reversible condition that can cause serious events, such as cerebral hemorrhage due to head trauma. Its occurrence is difficult to predict; therefore, this study aimed to develop machine learning (ML) models using heart rate variability (HRV) to predict the occurrence of VVS. Methods and Results We investigated 80 patients with syncope who underwent Holter monitoring during the head-up tilt test. Twenty-six ML models for the prediction of VVS using HRV parameters were examined. We randomly split the subjects into training and testing sets at a 7:3 ratio (training set: 46 positive and 9 negative subjects; testing set: 21 positive and 4 negative subjects). The XGB classifier achieved the highest performance compared with other algorithms (accuracy, 0.72; area under the curve, 0.801; sensitivity, 0.857; specificity, 0.621). When examining the time taken to predict syncope occurrence using the developed prediction model, it was found that the model could forecast approximately 3 min (equivalent to 193.2 beats) prior to the onset of symptoms. Conclusion The ML model utilizing HRV parameters was proficient in preemptively predicting VVS incidents. In practical applications, this approach can effectively enhance VVS prediction by leveraging the HRV, thereby aiding in the prevention of unforeseen accidents.

Selective use of implatable loop recorders improves diagnostic potential for unexplained syncope

Abstract Background Syncope remains a common medical problem with significant socio-economic consequences. Recently, the role of dedicated Syncope Units (SU) and implantable loop recorders (ILR) has emerged, in the investigation of unexplained syncope. Purpose To investigate the possibilities for a more rational and targeted use of various diagnostic tools. Methods In this retrospective study, 196 patients with Unexplained Syncope admitted in a single SU, between March 2019 and February 2023 were included. Various diagnostic tools were utilised during the investigational process, according to clinical judgement. Patients were retrospectively allocated into Group A including those who, among other tests, underwent ILR insertion and Group B including patients investigated without ILR implantation. Data were also compared with Group C, including patients assessed prior to SU establishment. Results There was no difference between Group A (n=133) and Group B (n=63) in the diagnostic yield (74% vs. 76%, p=0.22). There was significant difference between Group A and B regarding age (67.3 ± 16.9 years vs. 48.3 ± 19.1 years, p&amp;lt;0.001) and regarding cause of syncope (cardiogenic in 69% of group A and reflex syncope in 77% of group B, p&amp;lt;0.001). The diagnosis was based on electrocardiography (ECG) in 55% of group A and in 19% of group B (p&amp;lt;0.001). Time to diagnosis was 4.2 ± 2.7 months in patients with ILR implantation and 7.5 ± 5.6 months in Group B, p&amp;lt;0.001. In Group C, the diagnostic yield was 57.9% and the ECG-based diagnostic yield was 18.3%. Conclusions A selective use of ILR according to the clinical and electrocardiographic characteristics represents an acceptable diagnostic pathway that increases the effectiveness of the structured SU-approach by further preserving financial resources

Importance of the left superior ganglionated plexus ablation for the denervation of atrioventricular node: the impact of patient gender and bradycardia phenotype

Abstract Background Cardioneuroablation has been proposed as a new therapeutic option in selected patients with symptomatic functional bradyarrhythmia including recurrent neurally-mediated syncope. The contribution of individual ganglionated plexi to cardiac autonomic regulations is not fully established. Purpose It appears that ablation of the left superior ganglionated plexus (LSGP) is inoperable for the denervation of the sinoatrial node (SAN) and infrequently required for the denervation of the atrioventricular node (AVN). We explored the conditions that are associated with the need for LSGP ablation. Methods The study included 177 otherwise healthy patients aged 41 ± 12 years; 55% of males; 36% with predominant AVN disorder (29% in males, 44% in females, P &amp;lt;0.05) who underwent their first cardioneuroablation for symptomatic bradyarrhythmias at our centre between 2019 – 2024. Anatomically-navigated radiofrequency ablation with a bi-atrial approach was performed. In all patients, we ablated first the superior paraseptal (former right superior) ganglionated plexus (SPSGP) and inferior paraseptal (former posteromedial left) ganglionated plexus (IPSGP). Extracardiac vagus nerve stimulation (ECVS) via right and left jugular vein in general anaesthesia was used to assess the residual parasympathetic modulation of the AVN. If AVN was not completely denervated after the SPSGP and IPSGP ablation, the LSGP was targeted. Results Ablation of SPSGP and IPSGP resulted in SAN and AVN denervation in the majority of patients. LSGP ablation was required in 39 / 177 (22%) patients; in 31% of females vs. 14% of males (P &amp;lt;0.01); in 41% vs. 12% (P &amp;lt;0.0001) of patients with predominant AVN vs. SAN disorder, respectively. The corresponding decomposition is provided in the Table. In multivariate analysis, both female gender (P &amp;lt;0.05) and AVN disorder (P &amp;lt;0.001) were independently associated with the need for LSGP ablation. When the population was dichotomized into early (September 2019 – December 2021) and recent period (January 2022 – February 2024), the need for LSGP ablation had a downward trend (28% vs. 16%, P &amp;lt;0.05). Conclusions LSGP ablation to finalize the AVN denervation is required in a minority of patients. This need is independently associated with the female gender and predominant AVN disorder. The ECVS guidance in the ablation of SPSGP and IPSGP contributes to the decreasing trend of LSGP ablation, i.e. minimizing the final lesion set.Rate of LSGP ablation

Cardioneuroablation for the treatment of carotid sinus syndrome

Abstract Introduction Carotid sinus syndrome (CSS), characterized by exaggerated vagal responses leading to asystolic pauses with carotid sinus massage (CSM), often necessitates pacemaker implantation. This study investigates cardioneuroablation (CNA) as an alternative management strategy for CSS. Methods Prospective study of consecutive patients referred for CNA. All patients underwent CSM, atropine test, 24-hour Holter monitoring and SF-36 quality of life questionary before the procedure and at 6 months. The objective of the study was to assess syncope free survival, grade of cardioinhibition with CSM and heart rate variation (HRV) and quality of life after the procedure. Results A total of 13 patients (84.6% male, mean age 63.8 ± 12.3 years) were included. After a median follow-up of 11.2 (10.6-16.3) months, none of the patients experienced syncope (0%) and none of the patients required pacemaker implantation. After the procedure all the patients had a negative CSM and only one patient (7.7%) had a positive CSM at 6 months (Figure 1). There was an improvement in the energy and health change items in the SF-36 quality of life questionary (Figure 2). There was a reduction in HR increase in the atropine test at 6 months (pre-CNA: 66% (52-84) vs. post-CNA 27.4% (21.9-90.9); p=0.027) and in most of the 24-hour Holter monitoring HRV parameters. Conclusions Cardioneuroablation emerges as a promising and effective alternative to pacemaker implantation in managing cardioinhibitory CSS. Further research is warranted to solidify these findings and explore the long-term effects of CNA in this scenario.Figure 1Figure 2

Post-Exercise Syncope in a Previously Healthy 67-Year-Old Man: The Bezold–Jarisch Reflex and the Role of Autonomic Nervous System Dysfunction

A 67-year-old man started treatment due to frequent asymptomatic premature ventricular complexes (PVCs) accidentally being registered during a preventive examination by a specialist, because of which he was referred to cardiologist. During the initial 24-hour (h) ECG monitoring, 4.5% PVCs and one episode of asymptomatic non-sustained ventricular tachycardia (NSVT) with three PVCs in row, at a frequency of 150 beats per minute (bpm), were detected. After the introduction of beta blockers into therapy, a lower number of PVCs, without NSVT, were recorded in the control 24 h Holter ECG, while transthoracic echocardiography (TTE) showed normal left ventricular (LV) systolic function without cardiomyopathy. So, an exercise test was indicated, and it was interrupted in the third minute at 120 beats per minute (bpm) due to fatigue and pain in the hips, without malignant arrhythmias, angina or dyspneic complaints. During the rest period, a significant inferolateral depression of the ST junction was observed, which recovered in the ninth minute. Immediately after the ECG monitoring stopped, the patient lost consciousness; his pulse was not palpable, but breathing was audible, so cardiac massage was started. After he had regained consciousness, the ECG showed alternating sinus and junctional rhythm with the lowest frequency of 33 bpm, which was accompanied by marked hypotension (80/50 mmHg). The patient was immediately hospitalized; coronary angiography and repeated TTE were completely normal, while continuous ECG monitoring did not confirm malignant rhythm disorders or asystole. It was concluded that it was vasovagal syncope (VVS), most likely caused by the Bezold–Jarisch reflex (BJR).

Functional Syncope in Children and Adolescents: A Retrospective Cohort Study

BackgroundFunctional syncope, or psychogenic pseudosyncope, is often under-recognized. We aimed to show that functional syncope may be diagnosed in most pediatric patients by the initial neurological consultation. MethodsWe reviewed the medical records of patients who were evaluated from 2006 to 2022 in clinic for apparent transient loss of consciousness (a-TLOC) and probable functional syncope. Inclusion criteria included the following: (1) one or more episodes of a-TLOC; (2) spontaneous recovery; (3) age <19 years; (4) patients collapse or lie immobile andunresponsive to verbal stimulation; (5) normal or mildly increased heart rate and blood pressure, if assessed; (6) no other medical causes; and (7) episodes occurred during tilt, electroencephalography, or electrocardiogram or were seen by the author on a smartphone video or in clinic. Patients meeting criteria 1 to 7 were classified as “definite” functional syncope and those meeting criteria 1 to 6 as “probable” functional syncope. ResultsWe identified 31 patients with a-TLOC: 26 (23 females) had functional syncope, aged six to 17 years, whereas five were excluded (two functional seizures, one temporal lobe epilepsy, one vasovagal syncope, and one asthma). The clinical features of 13 patients in each group (definite versus probable) were not different statistically. Episodes were prolonged (1 to 270 minutes, mean 58 minutes) and frequent (daily or weekly in 65%), with eyes closed in 71% and eye flutter in 27%. After mean follow-up of 15 months in 14 patients: episodes disappeared in 29%, decreased >50% in 36%, and remained the same in 36%. ConclusionsFunctional syncope can be diagnosed at the initial neurological consultation without additional diagnostic testing in most patients.

Factors affecting the syncopal episodes in pediatric vasovagal syncope.

To investigate factors that influence the syncopal episodes in pediatric vasovagal syncope (VVS). A retrospective analysis was performed on the clinical data of 2908 children who were diagnosed with VVS for the first time between January 2001 and February 2023. The study examined the linear relationships among age, sex, height, weight, heart rate (HR), blood pressure, hemodynamic type, and head-up tilt test (HUTT) mode in relation to the onset of syncope. (1) Comparative analysis of intergroup differences revealed statistically significant variations in sex, age, height, weight, HR, systolic blood pressure, hemodynamic classification, and HUTT mode among syncopal episodes groups (P < 0.05); (2) Univariate analysis identified age, female, height, weight, VVS-cardioinhibited type (VVS-CI), VVS-mixed type (VVS-M) as potential risk factors for syncope episodes. Conversely, HR and sublingual nitroglycerin HUTT (SNHUT) emerged as potential protective factors against syncope episodes. (3) Multivariate analysis indicated that the frequency of syncope episodes increased by 0.27/0.02 for each unit increase in age/weight. When females compared to males and VVS-CI and VVS-M compared to VVS-vasoinhibited type (VVS-VI), the frequency of syncope episodes increased by 1.36, 0.53, and 0.66 respectively. Furthermore, SNHUT was associated with a reduction in the number of syncope episodes by 0.34 relative to basic HUTT. Female, age, weight, VVS-CI, and VVS-M were identified as independent risk factors for syncopal episodes, while SNHUT was recognized as an independent protective factor against syncopal episodes.

A higher peak heart rate during head-up tilt test predicts the therapeutic efficacy of metoprolol in vasovagal syncope

BackgroundAlthough beta blockers, such as metoprolol, have been widely used in the management of vasovagal syncope (VVS), their efficacy remains debated, with larger studies showing limited benefit. Identifying patient-specific characteristics that predict a positive response to metoprolol could optimize its use. This study aims to investigate the key factors that may determine which VVS patients are suitable candidates for metoprolol treatment.MethodsThis retrospective study was conducted at a single center. Patients diagnosed with VVS and treated with metoprolol for a minimum of three months were included. A 50% reduction in syncope symptom score (SS) after three months of metoprolol treatment was used to define metoprolol responders, while those who did not achieve this reduction were classified as non-responders. After a three-month follow-up, patients were divided into two groups: responders and non-responders. Baseline data—including age, gender, comorbidities, laboratory tests, and the type of VVS—were analyzed for each patient. Changes in heart rate (HR) and blood pressure during the head-up tilt test (HUTT) were also evaluated between the two groups. Logistic regression analysis was performed to identify potential predictors of metoprolol response, and receiver operating characteristic (ROC) curve analysis was used to assess the value of these predictors in selecting potential responders.ResultsA total of 168 VVS patients were enrolled between January 2016 and December 2020. Of these, 100 patients responded positively to metoprolol, while 68 did not. No significant differences in baseline characteristics or HUTT results were observed between the two groups (p > 0.05). However, responders exhibited a significantly higher peak HR compared to non-responders during the HUTT (120.13 ± 19.33 vs. 106.60 ± 22.32, p < 0.001). The increase in HR was also more pronounced in responders (0.60 ± 0.23 vs. 0.41 ± 0.25, p < 0.001). Additionally, HR variability was significantly greater in responders than in non-responders (16.18 ± 5.51 vs. 12.61 ± 5.50, p < 0.001).ConclusionHigher peak HR, larger increases in HR, and greater HR variability during the HUTT may serve as reliable predictors of a positive response to metoprolol in patients with VVS.