Long-term outcomes of cardioneuroablation with and without extra-cardiac vagal stimulation confirmation in severe cardioinhibitory neurocardiogenic syncope.

BACKGROUND: Cardioneuroablation (CNA) is a novel therapeutic approach for functional bradyarrhythmias, specifically neurocardiogenic syncope or atrial fibrillation, achieved through endocardial radiofrequency catheter ablation of vagal innervation, obviating the need for pacemaker implantation. Originating in the nineties, the first series of CNA procedures was published in 2005. Extra-cardiac vagal stimulation (ECVS) is employed as a direct method for stepwise denervation control during CNA. OBJECTIVE: This study aimed to compare the long-term follow-up outcomes of patients with severe cardioinhibitory syncope undergoing CNA with and without denervation confirmation via ECVS. METHOD: A cohort of 48 patients, predominantly female (56.3%), suffering from recurrent syncope (5.1 ± 2.5 episodes annually) that remained unresponsive to clinical and pharmacological interventions, underwent CNA, divided into two groups: ECVS and NoECVS, consisting of 34 and 14 cases, respectively. ECVS procedures were conducted with and without atrial pacing. RESULTS: Demographic characteristics, left atrial size, and ejection fraction displayed no statistically significant differences between the groups. Follow-up duration was comparable, with 29.1 ± 15 months for the ECVS group and 31.9 ± 20 months for the NoECVS group (p = .24). Notably, syncope recurrence was significantly lower in the ECVS group (two cases vs. four cases, Log Rank p = .04). Moreover, the Hazard ratio revealed a fivefold higher risk of syncope recurrence in the NoECVS group. CONCLUSION: This study demonstrates that concluding CNA with denervation confirmation via ECVS yields a higher success rate and a substantially reduced risk of syncope recurrence compared to procedures without ECVS confirmation.

Donor complication rates in whole blood, plasma and platelet donors: Age versus experience.

BACKGROUND: Many blood banks use upper age limits for donors out of concern for a higher donor complication rate in older donors. Experienced donors are known to have lower donor complication rates, and older donors are often more experienced, confounding the effect of age on donor complication rate. STUDY DESIGN AND METHODS: We studied donor complication rates in whole blood, plasma, and plateletpheresis donors from 2012 to 2022. Donor complication rates were compared between age groups in inexperienced (<20th donation) and experienced (≥20th donation) donors. In addition to this direct comparison, we made use of logistic regression with finer-grained experience groups, to further quantify the effects of age, experience and other factors on donor complication rate. RESULTS: While overall rate of vasovagal reaction was lower, rate of moderate/severe vasovagal syncope was highest in 70-79 year donors, however, only reached significance for plasma donors. Furthermore, rates of failed stab were highest in this age group. Hematoma rate showed a U-shaped pattern with regard to age, where the rate was not higher in the 70-79 year age group than in the 18-23 year age group. Pain decreased with age, however, rates were higher in the 70-79 year age group than in the 65-69 year age group. DISCUSSION: When properly accounting for donor experience, donor complication rate profiles clearly change with age. The increased risk for moderate/severe vasovagal syncope in older donors should be clearly communicated. Extra caution is needed if these donors are accepted for first-time donations.

Development and validation of a scoring system to predict vasovagal reaction upon whole-blood donation.

BACKGROUND AND OBJECTIVES: Risk factors for vasovagal reaction (VVR) have been extensively studied. With knowledge of the relative importance of these risk factors for VVR, collection staff could take care of blood donors from the same standpoint, leading to improved donor safety. We therefore developed a scoring system to predict VVR, which incorporates registration information. MATERIALS AND METHODS: Pre-syncopal and syncopal symptoms, as well as on- and off-site reactions, are included in this analysis as VVR. We defined the donor status as follows: first-time donors, repeat donors with no history of reaction and repeat donors with a history of reaction. We prepared two datasets: whole-blood donations at a blood donation site in Tokyo between January 2019 and December 2019 were included in training data (n = 361,114), and whole-blood donations between January 2020 and August 2020 were included in testing data (n = 216,211). RESULTS: The most important variable was the donor status, followed by age, estimated blood volume and height. We integrated them into a scoring system. Training and testing datasets were combined (n = 577,325), and VVR rates in groups with scores of 0, 1, 2, 3, 4 and 5 or more were 0.09% (95% CI: 0.081%-0.10%), 0.33% (95% CI: 0.31%-0.36%), 0.87% (95% CI: 0.78%-0.96%), 1.17% (95% CI: 1.05%-1.30%), 2.15% (95% CI: 1.98%-2.32%) and 3.11% (95% CI: 2.90%-3.34%), respectively. CONCLUSION: The scoring system enables staff to significantly predict VVR and may help them to identify donors at increased risk of experiencing syncope, thereby mitigating the negative impact of VVR on donor safety and return by paying close attention to high-risk donors.

Adult vasovagal syncope with abdominal pain diagnosed by head-up tilt combined with transcranial doppler: a preliminary study.

BACKGROUND: Syncope is a common condition that increases the risk of injury and reduces the quality of life. Abdominal pain as a precursor to vasovagal syncope (VVS) in adults is rarely reported and is often misdiagnosed.​. METHODS: We present three adult patients with VVS and presyncopal abdominal pain diagnosed by synchronous multimodal detection (transcranial Doppler [TCD] with head-up tilt [HUT]) and discuss the relevant literature. RESULTS: Case 1: A 52-year-old man presented with recurrent decreased consciousness preceded by six months of abdominal pain. Physical examinations were unremarkable. Dynamic electrocardiography, echocardiography, head and neck computed tomography angiography, magnetic resonance imaging (MRI), and video electroencephalogram showed no abnormalities. Case 2: A 57-year-old woman presented with recurrent syncope for 30 + years, accompanied by abdominal pain. Physical examination, electroencephalography, and MRI showed no abnormalities. Echocardiography showed large right-to-left shunts. Case 3: A 30-year-old woman presented with recurrent syncope for 10 + years, with abdominal pain as a precursor. Physical examination, laboratory analysis, head computed tomography, electrocardiography, and echocardiography showed no abnormalities. Syncope secondary to abdominal pain was reproduced during HUT. Further, HUT revealed vasovagal syncope, and synchronous TCD showed decreased cerebral blood flow; the final diagnosis was VVS in all cases. CONCLUSIONS: Abdominal pain may be a precursor of VVS in adults, and our findings enrich the clinical phenotypic spectrum of VVS. Prompt recognition of syncopal precursors is important to prevent incidents and assist in treatment decision-making. Abdominal pain in VVS may be a sign of sympathetic overdrive. Synchronous multimodal detection can help in diagnosing VVS and understanding hemodynamic mechanisms.

Making certain that noninvasive therapy for vasovagal syncope has failed before proceeding to invasive interventions.

There is a perceived need to express concisely the advice of guidelines in the context of consideration of invasive management of highly symptomatic vasovagal syncope. In response to this need the table is presented as a checklist and the text adds explanation and details. It is anticipated that this will prove to be of value for clinicians.

Temporal relationship between haemodynamic changes and activation of closed-loop stimulation during a tilt-induced vasovagal syncope.

AIMS: A dual-chamber pacemaker with closed-loop stimulation (CLS) mode is effective in reducing syncopal recurrences in patients with asystolic vasovagal syncope (VVS). In this study, we explored the haemodynamic and temporal relationship of CLS during a tilt-induced vasovagal reflex. METHODS AND RESULTS: Twenty patients underwent a tilt test under video recording 3.9 years after CLS pacemaker implantation. Three patients were excluded from the analysis because of no VVS induced by the tilt test (n = 1) and protocol violation (n = 2). In 14 of the remaining 17 patients, CLS pacing emerged during the pre-syncopal phase of circulatory instability when the mean intrinsic heart rate (HR) was 88 ± 12 b.p.m. and systolic blood pressure (SBP) was 108 ± 19 mmHg. The CLS pacing rate thereafter rapidly increased to 105 ± 14 b.p.m. within a median of 0.1 min [inter-quartile range (IQR), 0.1-0.7 min] when the SBP was 99 ± 21 mmHg. At the time of maximum vasovagal effect (syncope or pre-syncope), SBP was 63 ± 17 mmHg and the CLS rate was 95 ± 13 b.p.m. The onset of CLS pacing was 1.7 min (IQR, 1.5-3.4) before syncope or lowest SBP. The total duration of CLS pacing was 5.0 min (IQR, 3.3-8.3). Closed-loop stimulation pacing was not observed in three patients who had a similar SBP decrease from 142 ± 22 mmHg at baseline to 69 ± 4 mmHg at the time of maximum vasovagal effect, but there was no significant increase in HR (59 ± 1 b.p.m.). CONCLUSION: The reproducibility of a vasovagal reflex was high. High-rate CLS pacing was observed early during the pre-syncopal phase in most patients and persisted, although attenuated, at the time of maximum vasovagal effect. REGISTRATION: ClinicalTrials.gov identifier: NCT06038708.

Mechanism-based therapy of non-cardiac syncope: a practical guide.

The term non-cardiac syncope includes all forms of syncope, in which primary intrinsic cardiac mechanism and non-syncopal transient loss of consciousness can be ruled out. Reflex syncope and orthostatic hypotension are the most frequent aetiologies of non-cardiac syncope. As no specific therapy is effective for all types of non-cardiac syncope, identifying the underlying haemodynamic mechanism is the essential prerequisite for an effective personalized therapy and prevention of syncope recurrences. Indeed, choice of appropriate therapy and its efficacy are largely determined by the syncope mechanism rather than its aetiology and clinical presentation. The two main haemodynamic phenomena leading to non-cardiac syncope include either profound hypotension or extrinsic asystole/pronounced bradycardia, corresponding to two different haemodynamic syncope phenotypes, the hypotensive and bradycardic phenotypes. The choice of therapy-aimed at counteracting hypotension or bradycardia-depends on the given phenotype. Discontinuation of blood pressure-lowering drugs, elastic garments, and blood pressure-elevating agents such as fludrocortisone and midodrine are the most effective therapies in patients with hypotensive phenotype. Cardiac pacing, cardioneuroablation, and drugs preventing bradycardia such as theophylline are the most effective therapies in patients with bradycardic phenotype of extrinsic cause.

Interventions aimed to increase average 24-h systolic blood pressure reduce blood pressure drops in patients with reflex syncope and orthostatic intolerance.

AIMS: Systolic blood pressure (SBP) drops recorded by 24-h ambulatory blood pressure (BP) monitoring (ABPM) identify patients with susceptibility to reflex syncope and orthostatic intolerance. We tested the hypothesis that treatments aimed to increase BP (reassurance, education, and lifestyle measures plus pharmacological strategies) can reduce SBP drops. METHODS AND RESULTS: This was a multicentre, observational proof-of-concept study performed in patients with reflex syncope and/or orthostatic intolerance and with SBP drops on a screening ABPM. Among 144 eligible patients, 111 underwent a second ABPM on average 2.5 months after start of treatment. Overall, mean 24-h SBP increased from 114.1 ± 12.1 to 121.4 ± 14.5 mmHg (P < 0.0001). The number of SBP drops <90 and <100 mmHg decreased by 61%, 46% during daytime, and by 48% and 37% during 24-h period, respectively (P < 0.0001 for all). The dose-response relationship between difference in 24-h average SBP increase and reduction in number of SBP drops reached a plateau around ∼15 mmHg increase of 24-h SBP. The reduction in SBP drop rate was consistent and significant in patients who underwent deprescription of hypotensive medications (n = 44) and in patients who received BP-rising drugs (n = 67). CONCLUSION: In patients with reflex syncope and/or orthostatic intolerance, an increase in average 24-h SBP, regardless of the implemented strategy, significantly reduced the number of SBP drops and symptom burden. A 13 mmHg increase in 24-h SBP appears to represent the optimal goal for aborting the maximal number of SBP drops, representing a possible target for future interventions. ClincalTrials.gov identifier: NCT05729724.

Cardioneuroablation for vasovagal syncope: insights on patients' selection, centre settings, procedural workflow and endpoints-results from an European Heart Rhythm Association survey.

AIMS: Cardioneuroablation (CNA) is a catheter-based intervention for recurrent vasovagal syncope (VVS) that consists in the modulation of the parasympathetic cardiac autonomic nervous system. This survey aims to provide a comprehensive overview of current CNA utilization in Europe. METHODS AND RESULTS: A total of 202 participants from 40 different countries replied to the survey. Half of the respondents have performed a CNA during the last 12 months, reflecting that it is considered a treatment option of a subset of patients. Seventy-one per cent of respondents adopt an approach targeting ganglionated plexuses (GPs) systematically in both the right atrium (RA) and left atrium (LA). The second most common strategy (16%) involves LA GP ablation only after no response following RA ablation. The procedural endpoint is frequently an increase in heart rate. Ganglionated plexus localization predominantly relies on an anatomical approach (90%) and electrogram analysis (59%). Less utilized methods include pre-procedural imaging (20%), high-frequency stimulation (17%), and spectral analysis (10%). Post-CNA, anticoagulation or antiplatelet therapy is prescribed, with only 11% of the respondents discharging patients without such medication. Cardioneuroablation is perceived as effective (80% of respondents) and safe (71% estimated <1% rate of procedure-related complications). Half view CNA emerging as a first-line therapy in the near future. CONCLUSION: This survey offers a snapshot of the current implementation of CNA in Europe. The results show high expectations for the future of CNA, but important heterogeneity exists regarding indications, procedural workflow, and endpoints of CNA. Ongoing efforts are essential to standardize procedural protocols and peri-procedural patient management.

Classification of vasovagal syncope from physiological signals on tilt table testing.

BACKGROUND: The diagnostic test for vasovagal syncope (VVS), the most common cause of syncope is head-up tilt test (HUTT) assessment. During the test, subjects experienced clinical symptoms such as nausea, sweating, pallor, the feeling of palpitations, being on the verge of passing out, and fainting. The study's goal is to develop an algorithm to classify VVS patients based on physiological signals blood pressure (BP) and electrocardiography (ECG) obtained from the HUTT. METHODS: After 10 min of supine rest, the subject was tilted at a 70-degree angle on a tilt table for approximately a total of 35 min. 400 µg of glyceryl trinitrate (GTN) was administered sublingually after the first 20 min and monitoring continued for another 15 min. Mean imputation and K-nearest neighbors (KNN) imputation approaches to handle missing values. Next, feature selection techniques were implemented, including genetic algorithm, recursive feature elimination, and feature importance, to determine the crucial features. The Mann-Whitney U test was then performed to determine the statistical difference between two groups. Patients with VVS are categorized via machine learning models including Support Vector Machine (SVM), Gaussian Naïve Bayes (GNB), Multinomial Naïve Bayes (MNB), KNN, Logistic Regression (LR), and Random Forest (RF). The developed model is interpreted using an explainable artificial intelligence (XAI) model known as partial dependence plot. RESULTS: A total of 137 subjects aged between 9 and 93 years were recruited for this study, 54 experienced clinical symptoms were considered positive tests, while the remaining 83 tested negative. Optimal results were obtained by combining the KNN imputation technique and three tilting features with SVM with 90.5% accuracy, 87.0% sensitivity, 92.7% specificity, 88.6% precision, 87.8% F1 score, and 95.4% ROC (receiver operating characteristics) AUC (area under curve). CONCLUSIONS: The proposed algorithm effectively classifies VVS patients with over 90% accuracy. However, the study was confined to a small sample size. More clinical datasets are required to ensure that our approach is generalizable.

Comorbidity of behavioral problems and parental acceptance-rejection in children diagnosed with chest discomfort, palpitations, vasovagal syncope, and underlying heart disease: a multiple case-control study.

BACKGROUND: Children who experience chest discomfort, palpitations, vasovagal syncope, and underlying heart disease often present a complex clinical picture. Not only are they dealing with potential cardiac issues, but they may also exhibit behavioral problems that can complicate the diagnostic and treatment process. Moreover, parental acceptance or rejection can significantly influence the child's well-being and medical outcomes in such cases. This study aims to explore the comorbidity of behavioral problems and parental acceptance-rejection in children diagnosed with these cardiac symptoms and underlying heart disease. METHODS: In a case-control study, the Parental Acceptance - Rejection Questionnaire and Parental version of Strengths and Difficulties Questionnaire (SDQ) was filled by parents of 314 patients from pediatric cardiology clinic. RESULTS: The control group scored substantially lower overall according to SDQ. The vasovagal syncope subgroup was found to have considerably lower scores on the subscale. The group with chest discomfort scored highly in hostility and aggression in the PARQ. In comparison to the other groups, the vasovagal syncope and chest pain group demonstrated higher scores in undifferentiated rejection and total score. CONCLUSION: This study showed a correlation between children's behavioral and emotional problems and cardiac symptoms. This states that children's relationship with their parents has an impact on their symptoms. It will be necessary to conduct further studies to determine a causal association and devise preventative measures.

Serum uric acid predicts therapeutic response to midodrine hydrochloride in children with vasovagal syncope: a pilot study.

Serum uric acid (UA) level has been proven to be related to several cardiovascular and metabolic diseases. In the present study, we examined if baseline serum UA level could predict the therapeutic efficacy of midodrine hydrochloride on vasovagal syncope (VVS) in children. The pediatric VVS patients who received midodrine hydrochloride from November 2008 to October 2022 were enrolled. After a median treatment duration of 3 months, the therapeutic effect was evaluated. According to the patients' responses to midodrine hydrochloride, which was determined by the recurrence of syncope, they were divided into effective and ineffective groups. The baseline variables were explored using univariable and multivariate logistic analysis. The predictive efficacy was assessed by receiver operating characteristic curve (ROC), precision-recall curve (PR), Hosmer-Lemeshow test, calibration curve, and decision curve analysis (DCA). Totally, 53 participants were included in the study. Among the 51 patients who were successfully followed up, 29 (56.9%) responded to midodrine hydrochloride (effective group), and the other 22 (43.1%) failed to respond to midodrine hydrochloride (ineffective group). The participants in effective group had lower baseline serum UA level than those in ineffective group (276.5 ± 73 µmol/L vs. 332.7 ± 56 µmol/L, p = 0.004). Multivariable logistic analysis showed that serum UA was associated with the therapeutic response (odds ratio (OR): 0.985, 95% confidence interval (CI): 0.974-0.997, p = 0.01). ROC analysis indicated that using baseline serum UA < 299 µmol/L as a threshold value yielded a sensitivity of 77.3% and a specificity of 79.3% in predicting the treatment response to midodrine hydrochloride. The area under the PR curve was 0.833. Hosmer-Lemeshow test yielded a p value of 0.58, and calibration plot indicated that the model was well-fitted. DCA demonstrated that treatment decision depending on the baseline serum UA level resulted in a favorable net benefit.   Conclusion: This pilot study suggested that the baseline serum UA level could be taken as a predictor of therapeutic effect of midodrine hydrochloride on VVS in children. What is Known: • Empirical and unselected use of midodrine hydrochloride has an unfavorable therapeutic effect on VVS in children. Serum uric acid (UA) is closely linked to cardiovascular events. What is New: • A low baseline serum UA level successfully predicts the therapeutic effectiveness of midodrine hydrochloride on VVS in children.

Relationship between hemodynamic type and syncopal symptoms in pediatric vasovagal syncope.

Vasovagal syncope (VVS) is a clinically common neurally mediated syncope. The relationship between different hemodynamic types of VVS and clinical syncopal symptoms has not been reported. The purpose of this research is to explore relationship between hemodynamic types and syncopal symptoms in pediatric VVS. Two thousand five hundred thirteen patients diagnosed with VVS at the age of 3-18 years, average age was 11.76 ± 2.83 years, including 1124 males and 1389 females, due to unexplained syncope and pre-syncope from single-center of January 2001 to December 2021 were retrospectively analyzed. Subjects were divided into two groups according to the presence or absence of syncopal symptoms: syncope group (1262 cases) and pre-syncope group (1251 cases). (1) Baseline characteristics: age, height, weight, systolic blood pressure (SBP), and diastolic blood pressure (DBP) increased in the syncope group compared with the pre-syncope group; the composition ratio of females was more than that of males in the syncope group; and the composition ratio of VVS-cardioinhibited (VVS-CI) and VVS-mixed (VVS-M) was more in the syncope group than that of the pre-syncope group (all P < 0.05). (2) Univariate analysis: age, height, weight, SBP, DBP, female, VVS-CI, and VVS-M were potential risk factors for the presence of syncopal symptoms (all P < 0.05). (3) Multivariate analysis: VVS-CI and VVS-M were independent risk factors for the presence of syncopal symptoms, with an increased probability of 203% and 175%, respectively, compared to VVS-vasoinhibited (VVS-VI) (all P < 0.01). CONCLUSION: The hemodynamic type of pediatric VVS is closely related to the syncopal symptoms. WHAT IS KNOWN: • There are varying probabilities of syncopal episodes in different hemodynamic types of VVS, and there is a lack of research to assess the comparative risk of syncope in children with different hemodynamic types of VVS. WHAT IS NEW: • The probability in presence of syncopal symptoms varies greatly between different hemodynamic types of VVS. • VVS-CI and VVS-M had a 203% and 175% increased risk in presence of syncopal symptoms compared with VVS-VI, respectively.

Characteristics of deceleration capacity and deceleration runs in vasovagal syncope.

PURPOSE: Increased vagal activity plays a prominent role in vasovagal syncope (VVS). The aim of this study was to characterize vagal function in VVS by evaluating the heart rate (HR) deceleration capacity (DC) and the HR deceleration runs (DRs) in patients with VVS between attacks. METHODS: A total of 188 consecutive VVS patients were enrolled in the study, of whom 129 had positive head-up tilt test (HUTT); 132 healthy participants were enrolled as controls. DC, DRs (DR2, i.e., episodes of 2 consecutive beat-to-beat HR decelerations), and the sum of DR8-10 (very long DR [VLDR]) were calculated using 24-h electrograms. Clinical characteristics, DC, and DRs were compared among syncope groups and controls. RESULTS: Patients with VVS had higher DC (10.63 ± 2.1 vs. 6.58 ± 1.7 ms; P < 0.001) and lower minimum HR and DR6-10 than controls. No significant differences in DC or DR6-10 were found between the patients with positive and those with negative HUTT results. In multivariate logistic regression analysis, minimum HR ≥ 40 bpm (odds ratio [OR] 0.408, 95% confidence interval [CI] 0.167-0.989; P = 0.048), daytime DC ≥ 7.37 ms (OR 3.040, 95% CI 1.220-7.576; P = 0.013), and VLDR ≥ 0.046% (OR 0.306, 95% CI 0.138-0.679; P = 0.004) were demonstrated to be risk factors significantly associated with VVS. CONCLUSION: Compared to healthy controls, patients with VVS demonstrated distinct HR deceleration profiles between attacks, including overall higher DC and lower DR6-10.

Prevention strategies for vasovagal reaction in whole blood donors: A quadri-armed randomised control trial.

INTRODUCTION: Vasovagal reaction (VVR) is a frequently encountered generalised donor adverse reaction, associated with donor deterrence towards future donation. Several mitigation strategies for prevention of VVR were tried but still not standardised. This quadri-armed randomised study evaluated the utility of water ingestion, applied muscle tension (AMT) and combination of both in preventing the VVR among blood donors. METHODS: A quadri-armed randomised controlled trial was performed on 4320 whole blood donors. Blood donors of 18-65 years of age were randomised into four groups based on the interventions performed i.e., control with no intervention (Group 1, n = 1081), water ingestion (Group 2, n = 1082), AMT (Group 3, n = 1070) and combined intervention (Group 4, n = 1087). VVR during and immediately after blood donation were observed along with assessment of risk factors in blood donors and the effectiveness of interventions were analysed. RESULTS: The incidence of VVR observed 1.6% in our study, with the highest occurrence in the control group (2.5%) and the lowest in the combined intervention group (0.9%). Multivariable logistic regression revealed that the control group donors faced a 1.38-fold greater risk of VVR compared to those receiving interventions (OR: 1.38, 95% CI: 1.10-1.75). Other risk factors included younger age (OR: 1.5, 95% CI: 1.05-2.17), first-time donation (OR: 5.7, 95% CI: 1.66-5.74), prior history of VVR (OR: 2.5, 95% CI: 10.4-101.52). DISCUSSION/CONCLUSION: The combined approach of water ingestion and AMT proved significantly more effective in VVR prevention compared to individual interventions.

Diagnosis and treatment of recurrent syncope in a middle-aged women.

A 50-year-old female patient, presented with repeated syncope for more than 2 years. Prior assessments were conducted at different hospitals, but no definite abnormalities were found. The patient's fear and anxiety about possible future attacks were escalating. Through a Head-up tilt test, the cause was finally identified as vasovagal syncope. Following a 5-min administration of nitroglycerin, the patient reported palpitations, nausea, and deep, rapid breathing. The electrocardiogram initially showed a first-degree atrioventricular block, progressing swiftly to a second-degree type I atrioventricular block-high atrioventricular block. Immediate intervention was undertaken, but blood pressure was not instantly ascertainable, coinciding with an abrupt loss of consciousness. Subsequent electrocardiographic findings included paroxysmal third-degree atrioventricular block, sinus arrest, and complete cardiac arrest, prompting the initiation of external cardiac compressions. The longest recorded ventricular arrest approximated 15 s, with sinus rhythm resuming post 10 s of cardiac compressions and the patient regaining consciousness. The patient underwent vagal ablation and no longer experienced syncope.

Short-duration head-up tilt test potentiated with sublingual nitroglycerin in suspected vasovagal syncope: the fast Italian protocol.

BACKGROUND: The traditional nitroglycerin (NTG) head-up tilt test (HUTT) is time-consuming and the test duration is a barrier to widespread utilization in clinical practice. It was hypothesized that a short-duration protocol is not inferior to the traditional protocol regarding the positivity rate and has a similar distribution of hemodynamic response. METHODS AND RESULTS: Patients undergoing HUTT were randomized 1:1 to a 10 min passive phase plus a 10 min 0.3 mg NTG if the passive phase was negative (Fast) or to a 20 min passive phase plus a 15 min 0.3 mg NTG if the passive phase was negative (Traditional). A sample size of 277 patients for each group achieved 80% power to detect an expected difference of 0% with a non-inferiority margin of -10% using a one-sided t-test and assuming a significant level alpha of 0.025. A total of 554 consecutive patients (mean age 46.6 ± 19.3 years, 47.6% males) undergoing HUTT for suspected vasovagal syncope were randomly assigned to the Fast (n = 277) or Traditional (n = 277) protocol. A positive response was defined as the induction of syncope in presence of hypotension/bradycardia, and was observed in 167 (60.3%) patients with Fast and in 162 (58.5%) patients with the Traditional protocol. There was a trend of lesser vasodepressor response (14.8% Fast vs. 20.6% Traditional) which was significant during the passive phase (P = 0.01). CONCLUSION: The diagnostic value of the Fast HUTT protocol is similar to that of the Traditional protocol and therefore the Fast protocol can be used instead of the Traditional protocol.

Simulation training for medical emergencies: Evaluation of dentists' long-term learning skills and confidence.

INTRODUCTION: As the population ages and more patients experience medical emergencies during dental treatments, dentists must competently and confidently manage these situations. We developed a simulation training course for medical emergencies in the dental setting using an inexpensive vital sign simulation app for smartphones/tablets without the need for an expensive simulator. However, the duration for which this effect is maintained is unclear. This study was performed to evaluate the long-term educational effect at 3, 6, and 12 months after taking the course. MATERIALS AND METHODS: Thirty-nine dental residents participated in this course. Scenarios included vasovagal syncope, anaphylaxis, hyperventilation syndrome, and acute coronary syndrome, each of which the participants had to diagnose and treat. The participants were evaluated using a checklist for anaphylaxis diagnosis and treatment skills immediately after and 3, 6, and 12 months after the course. The participants were also surveyed about their confidence in diagnosing and treating these conditions by questionnaire before, immediately after, and 3, 6, and 12 months after the course. RESULTS: The checklist scores for anaphylaxis were significantly lower at 3, 6, and 12 months after the course than immediately after the course. The percentage of participants who provided a correct diagnosis and appropriate treatment for vasovagal syncope, hyperventilation syndrome, and acute coronary syndrome was lower at all reassessments than immediately after the course. CONCLUSION: Because medical emergency management skills and confidence declined within 3 months, it would be useful to introduce a refresher course approximately 3 months after the initial course to maintain skills and confidence.

The Seventh Prevention of Syncope Trial (POST VII)-A randomized clinical trial of atomoxetine for the prevention of vasovagal syncope: Rationale and study design.

BACKGROUND: Vasovagal syncope (VVS) is common, recurs, and is associated with markedly reduced quality of life, anxiety, and frequent injuries. The few pharmacological therapies for VVS proven to have a moderate benefit in reducing recurrences are limited to patients without coexisting conditions such as hypertension or heart failure. Although there is some data to suggest Atomoxetine, a norepinephrine reuptake transport inhibitor (NET), may be a promising treatment option, an adequately powered randomized placebo-controlled trial is needed. STUDY DESIGN: POST VII is a multicenter, randomized, double-blind, placebo-controlled, crossover study that will randomize 180 patients with VVS and at least 2 syncopal spells in the preceding year to a target daily dose of atomoxetine 80 mg daily or to a matching placebo, with an observation period of 6 months in each phase and with a 1-week washout period between phases. The primary end point will be the proportion of patients with at least one syncope recurrence in each arm analyzed with an intention-to-treat approach. The secondary end points include total syncope burden, quality of life, cost, and cost-effectiveness. POWER CALCULATIONS: Assuming a 33% relative risk reduction in syncope recurrence with atomoxetine, and a dropout rate of 16%, the enrollment of 180 patients will give an 85% power of reaching a positive conclusion about atomoxetine, with P = .05. CONCLUSIONS: This will be the first adequately powered trial to determine whether atomoxetine is effective in preventing VVS. If proven effective, atomoxetine might become the first-line pharmacological treatment for recurrent VVS.

Prospective randomized study comparing permanent pacing with rate drop response and closed loop stimulation in patients with vasovagal syncope where permanent pacing is indicated and selected as the appropriate treatment option.

BACKGROUND: Pacing for vasovagal syncope is established. Two pacing algorithms are available. The rate-drop-response (RDR-Medtronic) is triggered by falling heart rate acting with modified rate-hysteresis. The closed loop stimulation or system (CLS-Biotronik) is triggered by impedance changes in the right ventricle reflecting falling volume and rising contractility. These are very different physiologically. Both algorithms carry favorable reports in clinical use. METHODS: A randomized-controlled superiority trial is proposed to compare the two algorithms for the control of vasovagal syncope in patients for whom pacing is indicated by current guidelines in North America and Europe. Available recent evidence may be seen as supporting superiority of CLS. No comparison between the two algorithms has been made. In this trial, patients will be centrally randomized to one or other algorithm on a 1:1 basis. Two-hundred-seventy-six patients in each group will be recruited. Sample size is determined using a confidence interval of 95%, a power of 90%, and a drop-out rate of 10% to detect an 11% difference between CLS and RDR. Recurrent symptom comparison will be made by an independent committee. The Co-primary endpoints will be recurrent syncope burden compared with that in 24-months preimplant, and occurrence of syncope in 24-months follow-up. Each outcome will be compared between the two algorithms. Secondary endpoints will be program and drug therapy changes over 24-months follow-up and quality of life by questionnaire at baseline,1 and 2 years. RESULTS AND CONCLUSIONS: These are anticipated to clarify the device algorithm choice and, therefore, to improve patient care.