Frequent Syncope Research Articles

Postural Orthostatic Tachycardia Syndrome (POTS). Follow – Up of 25 cases

Background: Postural orthostatic tachycardia syndrome (POTS) is a clinical syndrome diagnosed when orthostatic intolerance and tachycardia appear in the standing position. POTS significantly impairs patients' quality of life. Aim: To report the symptoms, anamnestic and clinical elements, findings in the Tilt Test (HUT), evolution and treatment of POTS patients with a follow-up from 8 months to 28 years. Material and Methods: We reviewed from march 1996 to june 2024, 1269 HUT exams in our laboratory. Those reports in which orthostatic postural tachycardia and symptoms compatible with POTS appeared, were selected for analysis. Results: We identified 25 patients (2.6% of all positive Tilt test reports) with compatible signs and symptoms. Most patients complained of orthostatic intolerance, dizziness and frequent fainting. There was a delay of 8 -10 years between the onset of symptoms and the time of diagnosis. Orthostatic tachycardia and symptoms occurred on average after 3.5 and 5.2 minutes, respectively, when staying in the standing position. Our patients had a high frequency of syncope or presyncope in their families (60% frequency) and hypermobility joint syndrome (64% prevalence). 40% of the patients reported relief of their symptoms after being treated (most of them with fludrocortisone). Most patients that reported little or no relief, did not use medications or were treated for a short period. Conclusions: POTS is not common but significantly impairs the quality of life of those who suffer from it. We found a clear association with joint hypermobility syndrome, an excessive venous pooling during standing and a family history of syncope or lipothymia. Best treament is with fludrocortisone alone or in combination with midodrine.

Real-world safety data for MVA-BN: Increased frequency of syncope following intradermal administration for immunization against mpox disease

BackgroundMVA-BN vaccine (Jynneos, Imvamune, Imvanex) was used widely in the 2022 mpox outbreak. This experience provides real-world evidence about the vaccine’s safety, particularly regarding intradermal use. MethodsBavarian Nordic’s global safety database was searched for all adverse events following immunization (AEFIs) with MVA-BN. AEFI numbers were compared among administration routes. Selected events and administered doses were graphed over the mpox outbreak period. ResultsA total of 9585 AEFIs have been reported. The rate of myocarditis or pericarditis was <1 per 100,000 doses administered. Eighty-nine cases of syncope, fainting, or loss of consciousness were reported. This number rose after the August 2022 US emergency use authorization for intradermal administration, as did the proportion of all syncope AEFIs reported following intradermal administration (78,7 %). ConclusionReal-world data from large-scale administration of MVA-BN has confirmed the vaccine’s established safety profile when administered subcutaneously. Intradermal administration is likely associated with increased syncopal event frequency.

The prevalence and clinical features of syncope in patients with concealed Brugada Syndrome

Abstract Background Brugada Syndrome (BS) is an inherited rhythm-disorder with risk of sudden-cardiac-death defined by a specific ST-segment elevation pattern in precordial ECG-leads either spontaneous or provoked by Na-channel-blocker-drug-provocation-test with Ajmaline. Scarce data denote that the prevalence of non-arrhythmic syncope is high in BS and leads to diagnostic confusions. Head-up tilt test (HUT) is a diagnostic tool used to assess autonomic function in patients with suspicious syncopal events. Purpose Our aim was to elucidate the frequency of non-arrhythmic syncope in BS patients, compare it with non-BS population with suspicious syncope and reveal possible clinical relations. Methods Adult patients with an history of Ajmaline-induced BS and patients evaluated for suspicious syncope with non-arrhyhtmic-features without BS less than 55-years-old were prospectively and consecutively evaluated with resting and higher-inter-costal-space-ECGs (HICS-ECGs), cardiac-examination and routine HUT in our center. After the exclusion of subjects with resuscitated-sudden cardiac-death/documented-malignant-dysrhythmia, any cardiac-disease, anti-arrhythmic-use, bundle-branch-blocks, pre-excitations and ventricular hypertrophies; 52 BS(+) subjects ([mean±SD] age, 33,6±14, [range]18-55 years) (male n [%overall]:33 [63.2%]) and 35 age-sex matched BS(-)subjects ([mean±SD] age, 34,1±13, [range]18-55 years) were enrolled in the study. All ECGs and HUT test results were interpreted manually by two experienced cardiologists for BS and Brugada-type-ECG-patterns (BTEPs). Results The clinical characteristics of patients with and without BS and statistical findings are presented in Table-1. BS(+) patients were slimmer, revealing more BTEPs by baseline HICS-ECGs. Baseline heart-rates were lower, PR-intervals and P-wave-duration were significantly higher in BS(+) patients. HUT-positivity of BS(+) patients were significantly higher [(39% (n: 20 [male n: 13]) vs 19% (n: 7 [male n: 4]) (p= 0,01)] revealing significantly more mixed-syncope and orthostatic hypotension response in BS(+) subjects. No cardioinhibitory response was revealed. Conclusions Non arrhtymic syncope is found to be highly prevalent in middle-aged-subjects and especially males with BS (+) without an apparent cardiac-disorder. Knowing this considerably important clinical aspect might effect risk stratification algorithms and might prevent unnecessary high-risk interventions and device decisions. Non-invasive indices regarding the delayed conduction features in ECG characteristics of BS(+) patients and a higher vagal state might be proposed as one of the probable mechanisms revealing the higher prevalence of non-arrhythmic-syncope in BS.Table-1

Post-mortem examination of fatal acute type A aortic dissection: what does it teach us?

Acute type A aortic dissection (ATAAD) remains a highly life-threatening condition. This study investigates factors associated with fatal ATAAD prior to surgical treatment. We reviewed autopsy reports of ATAAD decedents who died before surgical intervention and underwent postmortem examination at our clinic from 1994 to 2022. Among 94 eligible cases, 50 (53.2%) decedents had DeBakey type I dissection, and 44 (46.8%) had DeBakey type II dissection. Most were males, 63 (67%), and 72 (77%) had a history of hypertension. The median age was 70.5 years, and the type II group was a decade older than the type I group (P < 0.001). Decedents in the type II group predominantly died during the first hour after symptoms onset 16 (52%), while in the type I group, fatalities occurred between 1 h and 1 day, 27 (66%). The most common site of the intimal tear was the midportion of the ascending aorta, 45 (48%). The median ascending aorta size was 5 cm for the entire cohort, 5.2 cm for type I and 4.6 cm for type II (P < 0.045). In this autopsy study of fatal acute aortic dissection, the median aortic size was below the current guideline threshold for elective repair. Type II acute aortic dissections were found more frequently than expected and were characterized by older age, advanced aortic atherosclerosis, smaller aortic size, a shorter interval from symptom onset to death and a higher frequency of syncope compared to type I dissection.

Exploring the impact of a KCNH2 missense variant on Long QT syndrome: insights into a novel gender-selective, incomplete penetrance inheritance mode.

Long QT syndrome (LQTS) is an inherited malignant arrhythmia syndrome that poses a risk of sudden death. Variants in the Potassium Voltage-Gated Channel Subfamily H Member 2 (KCNH2) gene are known to cause Long QT syndrome through an autosomal dominant inheritance pattern. However, as of now, there have been no reports of any KCNH2 variant leading to Long QT syndrome exhibiting incomplete penetrance that is influenced by gender. Whole-exome sequencing (WES) was conducted on the proband to identify pathogenic variants. Subsequently, Sanger sequencing was employed to validate the identified likely pathogenic variants in all family members. We analyzed a pedigree spanning three-generations afflicted by Long QT syndrome. WES revealed a novel KCNH2 missense variant (p.Val630Gly, c.1889T>G) as the causative factor for the family's phenotype. Within this family, all three male carriers of the KCNH2 variant carriers exhibited the Long QT syndrome phenotype: one experienced sudden death during sleep, another received an implantable cardioverter defibrillator (ICD), and a younger man displayed a prolonged QTc interval without any instances of syncope or malignant arrhythmia to date. Interestingly, the middle-aged female carrier showed no Long QT Syndrome phenotype. However, her offspring, diagnosed with Turner syndrome (45, X) and also a carrier of this variant, experienced frequent syncope starting at 12 years old and was diagnosed with Long QT syndrome, leading to an ICD implantation when she was 15 years old. These observations suggest that the manifestation of Long QT syndrome associated with this KCNH2 variant exhibits incomplete penetrance influenced by gender within this family, indicating potential protective mechanisms against the syndrome in females affected by this variant. Our investigation has led to the identification of a novel pathogenic KCNH2 variant responsible for Long QT syndrome within a familial context characterized by gender-selective, incomplete penetrance. This discovery highlights a unique pathogenic inheritance pattern for the KCNH2 gene associated with Long QT syndrome, and could potentially shed light on the distinct penetrance behaviors and patterns of the KCNH2 gene. This discovery broadens our exploration of the KCNH2 gene in cardiac arrhythmias, highlighting the intricate genetic dynamics behind Long QT syndrome.

Electrophysiological Characteristics and Ablation Outcomes in Patients With Catecholaminergic Polymorphic Ventricular Tachycardia.

Catheter ablation of premature ventricular contractions (PVCs) that trigger polymorphic ventricular tachycardia (PVT) or ventricular fibrillation has been reported as a novel therapy to reduce the syncope events in patients with catecholaminergic PVT, whereas the long-term ablation outcome and its value in improving exercise-induced ventricular arrhythmias remain unclear. Fourteen consecutive selected patients with catecholaminergic PVT (mean±SD age, 16±6 years; 43% male patients) treated with maximum β-blockers with no possibility of adding flecainide were prospectively enrolled for catheter ablation. The primary end point was syncope recurrence, and the secondary end point was the reduction of the ventricular arrhythmia score during exercise testing. Twenty-six PVT/ventricular fibrillation-triggering PVCs were identified for ablation. The trigger beats arose from the left ventricle in 50% of the cases and from both ventricles in 36% of the cases. Purkinje potentials were observed at 27% of the targets. After a mean follow-up of 49 months after ablation, 8 (57%) patients were free from syncope recurrence. Ablation of trigger beat significantly reduced the syncope frequency (mean±SD, 4.3±1.6 to 0.5±0.8 events per year; P<0.001) and improved the ventricular arrhythmia scores at the 3-month (5 [range, 3-6] to 1.5 [range, 0-5]; P=0.002) and 12-month (5 [range, 3-6] to 2 [range, 0-5]; P=0.014) follow-ups. The induction of nontriggering PVCs postablation was closely associated with syncope recurrence (hazard ratio, 6.8 [95% CI, 1.3-35.5]; P=0.026). Catheter ablation of PVT/ventricular fibrillation-triggering PVCs in patients with catecholaminergic PVT who cannot receive flecainide treatment seems to be a safe and feasible adjunctive treatment that may reduce the syncope burden and improve exercise-related ventricular arrhythmias. Induction of nontriggering PVCs after ablation is associated with a higher risk of syncope recurrence.

Permanent pacing versus cardioneuroablation for cardioinhibitory vasovagal syncope.

We compared the efficacy and safety of cardioneuroablation (CNA) vs. permanent pacing (PM) for recurrent cardioinhibitory vasovagal syncope (CI-VVS). One hundred sixty-two patients (CNA = 61, PM = 101), age 36 + 11years) with syncope frequency of 6.7 ± 3.9/year were included in this multicenter study. All patients with CNA were provided by a single center, while patients with PM were provided by 4 other centers. In the CNA arm, an electroanatomic mapping guided approach was used to detect and ablate ganglionated plexus sites. Dual chamber rate drop response (RDR) or close loop stimulation (CLS) transvenous and leadless pacemakers were implanted using standard technique. The primary endpoint was freedom from syncope. Of 101 patients in the PM group, 39 received dual-chamber pacemaker implants with the CLS algorithm, 38 received dual-chamber pacemakers with the RDR algorithm, and 24 received a leadless pacemaker. At 1-year follow-up, 97% and 89% in the CNA and PM group met the primary endpoint (adjusted HR = 0.27, 95% CI 0.06-1.24, p = 0.09). No significant differences in adverse events were noted between groups. There was no significant association between age (HR:1.01, 95% CI 0.96-1.06, p = 0.655), sex (HR:1.15, 95% CI 0.38-3.51, p = 0.809), and syncope frequency in the past year (HR:1.10, 95% CI 0.97-1.25, p = 0.122) and the primary outcome in univariable analyses. After adjustment for patient characteristics, the medium-term syncope recurrence risk of CI-VVS patients who underwent CNA was similar to that of a population of patients undergoing pacemaker implantation with a similar safety profile.

Abstract 14050: A Giant Free-Floating Ball Thrombus or a Tiny Fibroelastoma: Which Causes Multiple Strokes?

Background: Left atrial (LA) thrombus is not rare in patients with mitral valve stenosis, but in patients with nonvalvular atrial fibrillation on anticoagulation, the formation of a "ball thrombus" in the LA is uncommon. Case: A 73-year-old man with nonvalvular atrial fibrillation on eliquis presented with frequent syncope and slurred speech. .The appearance of the infarcts on brain MRI and involvement of different vascular territories suggests embolic phenomena as the cause. On transthoracic echo a large, highly mobile echo density in the left atrium was noted. Transesophageal echo revealed smoke in the left atrium and the left atrial appendage. A large round mobile echo density mass measuring 4.7 cm X 3.6 cm was seen in left atrium with no attachment to left atrium. A mobile round density measuring 0.7x0.7 cm was seen on the right coronary cusp. Absence of perfusion, no enhancement, and high signal intensity on T1 and T2 weighted images on cardiac MRI was suggestive organized clot in left atrium. Decision-making: Both masses were removed successfully. Pathology confirmed a large intact spherical organized clot from the LA and a small fibroelastoma attached to the aortic leaflet. Conclusion: This was a rare case of giant round-shaped left atrium thrombus, which occurred in a patient with nonvalvular atrial fibrillation on anticoagulation. An aortic fibroelastoma was also discovered by transesophegeal echo as another potential cause of stroke. The left atrial thrombus is thought to have developed from a small mural thrombus caused by prolonged blood stagnation, which gets rounded by the sculpting impact of multiple complex encounters with the atrial wall. This may then detach from the LAA and form a floating "ball thrombus.

The future of cardioneuroablation in cardiovascular medicine

ABSTRACT Introduction Cardioneuroablation is increasingly being utilized to improve outcomes in patients with vagally mediated bradyarrhythmias. However, there are still controversial issues in the field including patient selection, safety and efficacy, and procedural end-points. Areas covered In this review, the current role of cardioneuroablation is summarized, and controversial issues related to the modality are discussed. Expert opinion According to small open-label cohort studies, overall freedom from syncope recurrence was higher than 90% after cardioneuroablation in patients with vasovagal syncope (VVS). Use of the electrogram-based strategy or high-frequency stimulation demonstrate similar success rate except in procedures limited to the right atrium. Based on a recently published randomized controlled trial and metanalysis, it may be possible now to make a strong recommendation for cardioneuroablation in patients <40 years of age, and those with the cardioinhibitory or mixed type of VVS who continue to experience frequent and/or burdensome syncope recurrences. Considering patients with VVS are prone to significant placebo/expectation effect, sham-controlled trials may help to quantify the placebo effect. In well-selected patients with functional atrioventricular block and sinus bradycardia, may result in encouraging medium-term outcomes. However, functional bradycardia is identified in a minority of patients presenting with high-grade atrioventricular block or sinus node dysfunction.

ATOMOXETINE FOR SUPPRESSION OF VASOVAGAL SYNCOPE: A CLINICAL CASE SERIES

ATOMOXETINE FOR SUPPRESSION OF VASOVAGAL SYNCOPE: A CLINICAL CASE SERIES

A giant aneurysm of sinus of Valsalva presenting with frequent syncopal attacks

Sinus of Valsalva aneurysm is a rare congenital or acquired aortic root anomaly. The aneurysm has the potential to compress the adjacent structures or rupture to other cardiac chambers with fatal consequences. Patients might be asymptomatic or present with nonspecific cardiac symptoms. Once the diagnosis is made, prompt surgical repair is generally required. Here, we present a young woman with frequent syncope who was found to have a giant sinus of Valsalva aneurysm as the underlying etiology.

Pots syndrome: the importance of organic screening in anxiety patients. Case report

Introduction16-year-old female who starts psychiatric follow-up due to episodes of anxiety crises with dizziness and tremors.Objectives To expose a case in which it is essential to rule out organic pathology in cases where there is anxiety and physical symptoms.MethodsCase report and literature reviewResultsThe patient explains that she was in a situation of conflict with her ex-partner, commenting that he did not accept the breakup. Sertraline was prescribed in ascending doses up to 100 mg per day with complete remission of anxiety. 8 months later, she went to the emergency room for loss of consciousness and tremor of the lower limbs. She was diagnosed with conversive disorder and was prescribed lorazepam up to 3 mg per day. Since then, there has been a worsening in the frequency of syncope occurring up to 10 times a day, limiting her academic and social life. She was evaluated by a cardiologist who diagnosed Pots Syndrome (postural orthostatic tachycardia syndrome) and started treatment with ivabradine and mineralocorticoids. With this treatment, the episodes were drastically reduced and spaced out to 1-2 per week. The dose of lorazepam is decreased until its withdrawal without worsening of the anxious symptomatology.ConclusionsThis disorder consists of an involvement of the autonomic nervous system in which there is a sudden drop in blood pressure together with an abrupt increase in heart rate. Its treatment is based on increasing blood volume with drugs such as corticosteroids as well as postural measures with adequate water intake.DisclosureNo significant relationships.

Syncope as the Initial Manifestation of Advanced Nasopharyngeal Carcinoma: A Case Report

Carotid sinus syndrome is a principal cause of syncope in the elderly. Syncope, associated with carotid sinus syndrome which is secondary to metastasis of advanced nasopharyngeal carcinoma, rarely occurs. The current study reported a 66-year-old woman, who presented with a history of frequent and recurrent syncope as the initial symptom, and was eventually diagnosed with advanced nasopharyngeal carcinoma. The positron emission tomography scan demonstrated a diagnosis of advanced nasopharyngeal carcinoma with involvement in carotid sheath space, and nasopharyngeal biopsy revealed non-keratinized nasopharyngeal carcinoma. After diagnosis and treatment, the patient had no recurrence of syncope. In summary, our case study suggests that great importance should be attached to potential intrinsic causes of syncope especially in the case of nasopharyngeal carcinoma, as it is an insidious malignancy which needs to be precisely identified.

Psychogenic Pseudosyncope: Real or Imaginary? Results from a Case-Control Study in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) Patients.

Background and objectives: Orthostatic intolerance (OI) is a clinical condition in which symptoms worsen upon assuming and maintaining upright posture and are ameliorated by recumbency. OI has a high prevalence in patients with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). Exact numbers on syncopal spells especially if they are on a weekly or even daily basis are not described. Although not a frequent phenomenon, this symptomatology is of very high burden to the patient if present. To explore whether patients with very frequent (pre)syncope spells diagnosed elsewhere with conversion or psychogenic pseudosyncope (PPS) might have another explanation of their fainting spells than behavioral psychiatric disorders, we performed a case–control study comparing ME/CFS patients with and without PPS spells. Methods and results: We performed a case–control study in 30 ME/CFS patients diagnosed elsewhere with PPS and compared them with 30 control ME/CFS patients without syncopal spells. Cases were gender, age and ME/CFS disease duration matched. Each underwent a tilt test with extracranial Doppler measurements for cerebral blood flow (CBF). ME/CFS cases with PPS had a significant larger CBF reduction at end tilt than controls: 39 (6)% vs. 25 (4)%; (p < 0.0001). Cases had more severe disease compared with controls (chi-square p < 0.01 and had a p = 0.01) for more postural orthostatic tachycardia syndrome in cases compared with controls. PETCO2 end-tilt differed also, but the magnitude of difference was smaller than compared with the CBF reduction: there were no differences in heart rate and blood pressure at either end-tilt testing period. Compared with the test with the stockings off, the mean percentage reduction in cardiac output during the test with compression stockings on was lower, 25 (5) mmHg versus 29 (4) mmHg (p < 0.005). Conclusions: This study demonstrates that in ME/CFS patients suspected of having PPS, or conversion, CBF measurements end-tilt show a large decline compared with a control group of ME/CFS patients. Therefore, hypoperfusion offers an explanation of the orthostatic intolerance and syncopal spells in these patients, where it is clear that origin might not be behavioral or psychogenic, but have a clear somatic pathophysiologic background.

СИНКОПАЛЬНЫЕ СОСТОЯНИЯ: МУЛЬТИДИСЦИПЛИНАРНЫЙ ВЗГЛЯД НА СИСТЕМНУЮ ПРОБЛЕМУ

The results of the study of persons with syncope are presented. The aim of the study was to determine the frequency and cause of syncope in young people. Study of the relationship between syncope and diagnosed changes in laboratory, instrumental research methods and testing of psychoemotional status. In the course of the work, the method of social anonymous survey on the basis of Google Forms of medical university students was applied, the case histories of patients of the neurological department were analyzed. The reasons for syncope in the surveyed respondents in the study group were various mechanisms: neurogenic, reflex and orthostatic hypotension. According to the data of an in­depth examination of patients of the neurological department, the relationship between syncope and diagnosed nonspecific abnormalities in the results of laboratory and instrumental research methods was shown. An interdisciplinary approach has allowed us to expand our understanding of the mechanisms of syncope development and to prevent recurrent syncope.

Impact of supervised physical training on vasovagal syncope; a randomized controlled trial

Abstract Background Therapeutic interventions in vasovagal syncope (VVS) are centered on lifestyle modifications aimed to counteract the recognized mechanisms that precipitate syncope. In patients with recurrent VVS, supervised training might help reduce the symptomatic burden by increasing adherence to lifestyle modifications. Purpose We aimed to evaluate the effect of an integrated supervised training program versus standard care on syncopal recurrence rate among patients with VVS. Methods This randomized, controlled, 1:1 parallel-design, open-label trial was conducted between November 2019 and February 2021. Eligible patients were those aged between 18 and 70 years with newly-diagnosed medication-naïve VVS who had experienced ≥2 syncopal episodes in the prior year. All participants received education and reassurance about the benign nature of VVS, were advised to increase salt and fluid intake, and practice counter-pressure maneuvers based on 2018 European Society of Cardiology syncope guideline (standard care). Patients were randomized to standard VVS care or the training program. The intervention program consisted of thrice-weekly four-hours-long sessions during the first month after randomization; including tilt training, aerobic exercise (with rowing ergometer, recumbent biking), and standardized counter-pressure maneuvers supervised by a team of physical medicine and rehabilitation specialist and a cardiologist. After the first month, the intervention group were planned to attend a four-hours-long session every three months. The control group were followed by phone calls after the initial visit every three months. The intended follow-up duration was one year and the primary outcome was time to first syncopal episode. Results Out of 332 patients screened, 50 (mean age: 33.5 years; 64% female, figure 1) were equally randomized. Follow-up was completed for all participants. After one year, there was a significant reduction in syncope with supervised training compared to standard care (hazard ratio: 0.28; 95% confidence interval: 0.11 to 0.68; p=0.005, figure 2). Furthermore, frequency of syncope was lower in the supervised training arm versus standard of care (median [interquartile range]: 0 [0–1] versus 1 [0–3]; p=0.017). Conclusions In patients with recurrent VVS, supervised training showed promising results in reducing syncopal recurrence. Future research should focus on similar approaches to alter patients' lifestyle as an effective treatment for VVS. Funding Acknowledgement Type of funding sources: Public Institution(s). Main funding source(s): Tehran University of Medical Sciences Figure 1Figure 2

Syncope and COVID-19 disease - A systematic review.

BackgroundSyncope is not a common manifestation of COVID-19, but it may occur in this context and it can be the presenting symptom in some cases. Different mechanisms may explain the pathophysiology behind COVID-19 related syncope. In this report, we aimed to examine the current frequency and etiology of syncope in COVID-19.MethodsA systematic review across PubMed, ISI Web of Knowledge and SCOPUS was performed, according to PRISMA guidelines, in order to identify all relevant articles regarding both COVID-19 and syncope.ResultsWe identified 136 publications, of which 99 were excluded. The frequency of syncope and pre-syncope across the selected studies was 4.2% (604/14,437). Unexplained syncope was the most common type (87.9% of the episodes), followed by reflex syncope (7.8% of the cases). Orthostatic hypotension was responsible for 2.2% of the cases and syncope of presumable cardiac cause also accounted for 2.2% of cases. Arterial hypertension was present in 52.0% of syncope patients. The use of angiotensin receptor blockers or angiotensin converting enzyme inhibitors were not associated with an increased incidence of syncope (chi-square test 1.07, p 0.30), unlike the use of beta-blockers (chi-square test 12.48, p < 0.01).ConclusionSyncope, although not considered a typical symptom of COVID-19, can be associated with it, particularly in early stages. Different causes of syncope were seen in this context. A reevaluation of blood pressure in patients with COVID-19 is suggested, including reassessment of antihypertensive therapy, especially in the case of beta-blockers.

B-PO05-192 DUAL CHAMBER CLOSED LOOP STIMULATION PACING PREVENTS CARDIOINHIBITORY SYNCOPE IN YOUNG PATIENTS

Cardioinhibitory syncope (CIHS) is a subtype of neurocardiogenic syncope (NCS) characterized by abrupt bradycardia/long sinus pauses and syncope with minimal prodrome and is often refractory to standard therapies. The BiotronikTM DDD-CLS (Closed Loop Stimulation) algorithm paces preemptively in response to beat-to-beat surges in cardiac contractility to prevent CIHS syncope. To evaluate the efficacy of DDD-CLS pacing to prevent CIHS syncope in young patients. All patients with CIHS onset before age 18 and treated with DDD-CLS pacemaker at our institution from 2008-2020 were included as well as 2 patients with drug-refractory NCS without long pauses. Retrospective chart review assessed diagnostics and patient reported onset, duration and frequency of syncope. Eleven patients (9 female) received DDD-CLS pacemakers for CIHS (9pts) or drug-refractory NCS with bradycardia (2pts). Long sinus pauses (median 17 sec/range 7-26 sec) were recorded in 9 patients with CIHS. Median age at implant was 16.2 (11-26) years. Onset of syncope was a median of 4.5 (0.3-16.5) years prior to implant and median follow up after implant was 6.9 (0.25-12) years. Patient reported syncope decreased from 7.0/pt-yr to 0.28/pt-yr (p< 0.003 by Wilcoxon Signed-Rank test). Four patients experienced 7 total episodes of syncope after DDD-CLS pacing. Seven pts had no recurrences, including one patient who failed prior DDD pacemaker treatment. DDD-CLS was highly effective at eliminating or reducing CIHS in young patients. Its potential role for patients with typical NCS warrants further evaluation.

B-PO01-027 PERMANENT PACING VERSUS CARDIONEUROABLATION FOR CARDIOINHIBITORY VASOVAGAL SYNCOPE

Permanent cardiac pacing (PM) can reduce syncopal events in patients with refractory cardioinhibitory (CI) vasovagal syncope (VVS). Cardioneuroablation (CNA) has been shown to be effective in reducing syncopal recurrences in patients with CI-VVS. To compare the safety and efficacy of CNA with PM in patients with recurrent CI-VVS. We conducted a 5-center, retrospective study of all patients who underwent CNA or received PM for recurrent, severe, CI-VVS. Clinical diagnosis of CI-VVS was supported by cardiac monitoring or positive cardioinhibitory response to head-up tilt testing. All patients had disabling symptoms with traumatic syncope despite conservative therapies. The primary efficacy endpoint was freedom from syncope during follow up. Any procedure-related adverse events (AE) were also assessed. 162 patients (CNA [n=61], PM [n=101]) with age 36+11 years (64 % female) and syncope frequency of 6.7±3.9/year were included. In patients undergoing CNA, age (35 + 12 vs 36 + 11, p =0.581) and pre-procedure syncope frequency [median 5 (IQR 4-8) vs median 6 (IQR (4-10), p = 0.52) were similar, and proportion of women lesser compared to the PM group (40.9% vs 77.2%, p <0.001). At 1-year, 96.7% (59/61) and 89.1% (90/101) met primary efficacy endpoint in the CNA and PM groups (unadjusted HR=0.30, 95% CI 0.07 - 1.34, p=0.119, p=NS, adjusted HR=0.27, 95% CI 0.06 - 1.24, p=0.09) (Figure 1). Major and minor AE occurred in 5/61 in the CNA and 11/101 in the cardiac pacing groups (p=0.79). In patients with CI-VVS, CNA demonstrated equivalent efficacy in reducing syncopal events when compared to cardiac pacing, with a similar safety profile.

Atypical vasovagal syncope in Cavalier King Charles spaniel ocurring at rest

A 10-year-old male entire Cavalier King Charles Spaniel was referred for investigation of frequent episodes of transient loss of consciousness during periods of rest as well as severe stertor and inspiratory dyspnoea. Echocardiography revealed degenerative mitral valve disease in stage B1 ACVIM (Keene et al., 2019) without any evidence of pulmonary hypertension. Respiratory tract endoscopic examination revealed a significantly enlarged soft palate, laryngeal saccule eversion and severe laryngeal collapse. During syncopal episodes, Holter examination revealed progressive bradycardia with long periods of sinus and ventricular arrest, followed by paroxysmal runs of atrial fibrillation, suggestive of reflex syncope. This case describes a dog with reflex syncope occurring in an atypical situation of rest with spontaneous improvement of syncope frequency until its complete resolution 6 months after presentation. Un cavalier King Charles Spaniel mâle entier de 10 ans est référé pour l’investigation d’épisodes de perte de conscience fréquents au repos, ainsi que pour l’exploration d’un stertor et d’une dyspnée inspiratoire marqués. Une échocardiographie a mis en évidence une maladie dégénérative valvulaire mitrale en stade B1 ACVIM (Keene et al., 2019) sans hypertension pulmonaire. Une endoscopie respiratoire a révélé une élongation marquée du palais mou, une éversion des ventricules laryngés et un collapsus laryngé important. Lors des épisodes de syncope, l’examen Holter a révélé une bradycardie progressive avec de longues périodes d’arrêt sinusal avec une asystolie ventriculaire, suivies par une série de fibrillation atriale, évoquant une syncope réflexe. Ce cas décrit un cas de syncope réflexe sur un chien survenant au repos, avec une amélioration spontanée des crises jusqu’à sa complète résolution 6 mois après présentation.