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.

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.

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.

Pre-donation water and salty snacks to prevent vasovagal reactions among blood donors.

BACKGROUND: Minimizing the risk of vasovagal reactions (VVRs) can prevent donor harms and improve donor return. We report the results of a program to reduce VVR rates. STUDY DESIGN AND METHODS: The program was implemented on June 11, 2017 and consisted in drinking water and eating a salty snack before donating blood, plasma, or platelets. All donations made during the "pre-program period" (October 11, 2015-June 10, 2017) and "post-program period" (June 11, 2017-May 11, 2019) were included. Study outcomes comprised VVRs (any severity) and syncopal VVRs, whether employee- or donor-reported. An interrupted time series (ITS) analysis proxied causality based on the "pre-program trend," the "immediate trend" (i.e., immediately before versus after the program), and the "post-program trend". The relative risk (RR) of VVR (along with confidence intervals [CIs]) was reported, overall and stratified by subgroups based on age, sex, donor type (i.e., first-time versus repeat), and donation type (i.e., whole blood versus apheresis). RESULTS: The monthly VVR rate (any severity) dropped from 4.6% in the pre-program period to 4.3% in the post-program period, and never reached its pre-program level. The ITS analysis revealed a statistically significant and increasing pre-program trend (RR [95% CI] = 1.011 [1.002-1.020]), a statistically significant and decreasing immediate trend (RR [95% CI] = 0.848 [0.743-0.969]), and a non-statistically-significant and stable post-program trend (RR [95% CI] = 0.999 [0.993-1.006]). Similar trends were observed for nearly all high- and low-risk subgroups. No statistically significant trend was observed for syncopal VVRs. DISCUSSION: These results suggest that the herein-described program durably reduced the incidence of VVRs (any severity) by ~15%.

A new risk predictive scoring system of vasovagal reactions in patients with preoperative autologous blood donation.

BACKGROUND AND OBJECTIVES: Vasovagal response (VVR) is the most common adverse reaction during blood donation and it is the main element for the safety of the patients with preoperative autologous blood donation (PABD). Accurate identification high-risk group is of great significance for PABD. Our study aimed to establish a scoring system based on the nomogram to screen the high-risk population and provide evidence for preventing the occurrence of VVRs. MATERIALS AND METHODS: A number of 4829 patients underwent PABD between July 2017 and June 2020 in the first medical center of Chinese PLA Hospital were recruited, 3387 of whom were included in the training group (70 %; 108 VVRs patients vs 3279 Non-VVRs patients), 1442 were included in the validation group (30 %; 46 VVRs patients vs 1396 Non-VVRs patients). The data were analyzed by univariate and multivariate logistic regression. The nomogram of the scoring system was created by using the RMS tool in R software. RESULTS: Seven variables including BMI, hematocrit, pre-phlebotomy heart rate and systolic blood pressure, history of blood donation, age group and primary disease were selected to build the nomogram, which was shown as prediction model. And the score was 0-1 for BMI, 0-2 for hematocrit, systolic blood pressure, heart rate and no blood donation history, 0-10 for age, 0-3 for primary disease. When the total cutoff score was 11, the predictive system for identifying VVRs displayed higher diagnostic accuracy. The area under the curve, specificity, and sensitivity of the training group were 0.942, 82.41 % and 97.17 %, respectively, whereas those of the validation group were 0.836, 78.26 % and 78.15 %, respectively. CONCLUSION: A risk predictive scoring system was successfully developed to identify high-risk VVRs group form PABD patients that performed well.

Serotonin reuptake inhibition for the prevention of vasovagal syncope: a systematic review and meta-analysis.

PURPOSE: Vasovagal syncope is a common clinical condition that lacks effective medical therapies despite being associated with significant morbidity. Current guidelines suggest that serotonin-specific reuptake inhibitors might suppress vasovagal syncope but supporting studies have been small and heterogenous. The purpose of this study was to evaluate the efficacy of serotonin-specific reuptake inhibitors to prevent syncope in patients with recurrent vasovagal syncope by conducting a systematic review and meta-analysis of published studies. METHODS: Relevant randomized controlled trials were identified from the MEDLINE and Embase databases without language restriction from inception to August 2022, and ClinicalTrials.gov. All studies were conducted in clinical syncope populations and compared the benefit of serotonin versus placebo. Weighted relative risks were estimated using random effects meta-analysis techniques. RESULTS: Three studies (n = 204) met inclusion criteria. Patients were 42 ± 13 years of age and 51% female. Serotonin-specific reuptake inhibitors were found to substantially reduce the likelihood of a patient having at least one recurrence of vasovagal syncope [relative risk (RR) 0.34 (0.20-0.60), p < 0.01] with minimal between-study heterogeneity (I2 = 0%, p = 0.67). Serotonin-specific reuptake inhibitors in two reports provided significant protection against clinical presyncope [RR 0.43 (0.24-0.77), p < 0.01], with minimal between-study heterogeneity (I2 = 0%, p = 0.80). CONCLUSIONS: Serotonin-specific reuptake inhibitors may be effective in preventing syncope induced by head-up tilt testing and in syncope in the community in randomized, double-blinded clinical trials.

Pain associated with intravascular instrumentation reduces orthostatic tolerance and predisposes to vasovagal reactions in healthy young adults without needle phobia: a randomised controlled study.

PURPOSE: Vasovagal syncope (VVS), or fainting, is frequently triggered by pain, fear, or emotional distress, especially with blood-injection-injury stimuli. We aimed to examine the impact of intravenous (IV) instrumentation on orthostatic tolerance (OT; fainting susceptibility) in healthy young adults. We hypothesized that pain associated with IV procedures would reduce OT. METHODS: In this randomised, double-blind, placebo-controlled, cross-over study, participants (N = 23; 14 women; age 24.2 ± 4.4 years) underwent head-up tilt with combined lower body negative pressure to presyncope on three separate days: (1) IV cannulation with local anaesthetic cream (EMLA) (IV + EMLA); (2) IV cannulation with placebo cream (IV + Placebo); (3) sham IV cannulation with local anaesthetic cream (Sham + EMLA). Participants rated pain associated with IV procedures on a 1-5 scale. Cardiovascular (finger plethysmography and electrocardiogram; Finometer Pro), and forearm vascular resistance (FVR; brachial Doppler) responses were recorded continuously and non-invasively. RESULTS: Compared to Sham + EMLA (27.8 ± 2.4 min), OT was reduced in IV + Placebo (23.0 ± 2.8 min; p = 0.026), but not in IV + EMLA (26.2 ± 2.2 min; p = 0.185). Pain was increased in IV + Placebo (2.8 ± 0.2) compared to IV + EMLA (2.0 ± 2.2; p = 0.002) and Sham + EMLA (1.1 ± 0.1; p < 0.001). Orthostatic heart rate responses were lower in IV + Placebo (84.4 ± 3.1 bpm) than IV + EMLA (87.3 ± 3.1 bpm; p = 0.007) and Sham + EMLA (87.7 ± 3.1 bpm; p = 0.001). Maximal FVR responses were reduced in IV + Placebo (+ 140.7 ± 19.0%) compared to IV + EMLA (+ 221.2 ± 25.9%; p < 0.001) and Sham + EMLA (+ 190.6 ± 17.0%; p = 0.017). CONCLUSIONS: Pain plays a key role in predisposing to VVS following venipuncture, and our data suggest this effect is mediated through reduced capacity to achieve maximal sympathetic activation during orthostatic stress. Topical anaesthetics, such as EMLA, may reduce the frequency and severity of VVS during procedures requiring needles and intravascular instrumentation.

Implementation of supervised physical training to reduce vasovagal syncope recurrence: A randomized controlled trial.

INTRODUCTION: Physical techniques used for the prevention of vasovagal syncope have limited evidence for efficacy. We aimed to evaluate multimodal supervised physical training as a treatment approach. METHODS: In this 1:1 randomized trial, patients with ≥2 episodes of clinically diagnosed vasovagal syncope were included. On top of standard care, the intervention arm performed supervised tilt training and aerobic exercise in six sessions at a cardiac rehabilitation center (three sessions during the first month, and then at 3-month intervals), plus home tilt training. The control arm received standard care with a similar protocol of home tilt training. The primary outcome was time to first syncopal recurrence during 1 year of follow-up. RESULTS: Fifty participants were randomized (mean age: 34.5 ± 14.8 years; 64% female). The rate of syncopal recurrence was 28% and 64% within the intervention and control arms, respectively, with significantly higher syncope-free survival at 1 year in the intervention arm (Log-rank p = .003). The frequency of recurrent syncopal events was significantly lower with physical training (p = .017). Participants in the intervention arm reported significantly higher adherence to the home tilt training program (80% vs. 52%; p = .037). CONCLUSION: Among patients with recurrent vasovagal syncope, a supervised program of tilt training and aerobic exercise reduced syncopal recurrence. Future trials are warranted to further investigate multimodal supervised physical techniques as a therapeutic approach in treating vasovagal syncope.

An intervention study for the prevention of vasovagal reactions and evaluating donors' experience: Analysis of donors' return for subsequent donation.

BACKGROUND AND OBJECTIVES: The EPISoDe (Experience Success in Donation) study investigated the effect of interventions on self-reported vasovagal reactions (VVRs) in first-time and novice (second to fourth donation) whole blood donors aged ≤30 years, demonstrating a 23% reduction of VVR from water drinking shortly before donation in the novice donors. Because donation experience and complications affect donor retention, we analysed intervention group donors' return for subsequent donation, a predefined secondary outcome. MATERIALS AND METHODS: The interventions were as follows: 330 ml water, 500 ml water, ball squeezing before phlebotomy (placebo) and a control group. All donors received an online questionnaire about their experience within a week after donation. In the Netherlands, eligible donors are invited at least yearly depending on hospitals' needs. We analysed attendances within 421 days through return percentages and binomial logistic regression. RESULTS: Of the 8300 EPISoDe participants, 6538 (78.8%) returned within 421 days. Return did not differ between the two water groups, whereas odds for return were significantly higher in both water and placebo intervention donors compared to the control group (odds ratio [OR] 1.14, 95% confidence interval [CI] 1.00-1.29 and 1.22, 1.05-1.43, respectively) after adjustment for occurrence of VVR, unsuccessful collection, gender and donation history. Staff-recorded or self-reported VVR at index donation was associated with reduced odds for return (OR 0.47, 95% CI 0.37-0.60 and OR 0.53, 95% CI 0.46-0.61, respectively). CONCLUSION: In this cohort of younger inexperienced blood donors, 78.8% returned for subsequent donation. Donors who received an active study intervention, either water or placebo, were more likely to return than control group donors.

Social Contagion of Vasovagal Symptoms in Blood Donors: Interactions With Empathy.

BACKGROUND: Vasovagal reactions (VVRs) are commonly experienced in medical situations such as blood donation. Many believe that psychosocial contagion can contribute to the development of VVRs, but this is largely clinical lore. PURPOSE: The goal of the present investigation was to examine the physiological effects of observing another experience a reaction, focusing on the potential moderating effects of empathy. METHODS: This study was part of a randomized controlled trial of behavioral techniques on the prevention of VVRs in blood donors. The sample was composed of 530 healthy university students. Measures of symptoms were obtained with the Blood Donation Reactions Inventory (BDRI) and through observation. Physiological variables were measured using respiratory capnometry and a digital blood pressure monitor. The Affective and Cognitive Measure of Empathy was administered to 230 participants. RESULTS: Donors who witnessed another experiencing a reaction were more likely to spontaneously report symptoms during the blood draw, to be treated for a reaction, to score higher on the BDRI, and to exhibit smaller compensatory heart rate increases. Donors with higher affective empathy reported more symptoms, exhibited hyperventilation, and were more likely to be treated. Donors with higher cognitive empathy were less likely to require treatment if they witnessed a reaction. CONCLUSION: These results suggest that psychosocial contagion of physical symptoms can occur. The moderating effects of empathy differed depending on the subtype of empathy. Perhaps a better cognitive understanding of how other people are feeling functions as a coping response, whereas feeling sympathetic about others' distress increases one's own.

Midodrine for the prevention of vasovagal syncope: a systematic review and meta-analysis.

AIMS: Vasovagal syncope (VVS) is a common clinical condition that lacks effective medical therapies despite being associated with significant morbidity. Current guidelines suggest that midodrine, a prodrug for an α1-adrenergic receptor agonist, might suppress VVS but supporting studies have utilized heterogeneous methods and yielded inconsistent results. To evaluate the efficacy of midodrine to prevent syncope in patients with recurrent VVS by conducting a systematic review and meta-analysis of published studies. METHODS AND RESULTS: Relevant randomized controlled trials were identified from the MEDLINE, Embase, CENTRAL, and CINAHL databases without language restriction from inception to June 2021. All studies were conducted in clinical syncope populations and compared the benefit of midodrine vs. placebo or non-pharmacological standard care. Weighted relative risks (RRs) were estimated using random effects meta-analysis techniques. Seven studies (n = 315) met inclusion criteria. Patients were 33 ± 17 years of age and 31% male. Midodrine was found to substantially reduce the likelihood of positive head-up-tilt (HUT) test outcomes [RR = 0.37 (0.23-0.59), P < 0.001]. In contrast, the pooled results of single- and double-blind clinical trials (I2 = 54%) suggested a more modest benefit from midodrine for the prevention of clinical syncope [RR = 0.51 (0.33-0.79), P = 0.003]. The two rigorous double-blind, randomized, placebo-controlled clinical trials included 179 VVS patients with minimal between-study heterogeneity (I2 = 0%) and reported a risk reduction with midodrine [RR = 0.71 (0.53-0.95), P = 0.02]. CONCLUSIONS: Midodrine is effective in preventing syncope induced by HUT testing and less, but still significant, RR reduction in randomized, double-blinded clinical trials.

Midodrine for the Prevention of Vasovagal Syncope : A Randomized Clinical Trial.

BACKGROUND: Recurrent vasovagal syncope is common, responds poorly to treatment, and causes physical trauma and poor quality of life. Midodrine prevents hypotension and syncope during tilt tests in patients with vasovagal syncope. OBJECTIVE: To determine whether midodrine can prevent vasovagal syncope in usual clinical conditions. DESIGN: Randomized, double-blind, placebo-controlled clinical trial. (ClinicalTrials.gov: NCT01456481). SETTING: 25 university hospitals in Canada, the United States, Mexico, and the United Kingdom. PATIENTS: Patients with recurrent vasovagal syncope and no serious comorbid conditions. INTERVENTION: Patients were randomly assigned 1:1 to placebo or midodrine and followed for 12 months. MEASUREMENTS: The primary outcome measure was the proportion of patients with at least 1 syncope episode during follow-up. RESULTS: The study included 133 patients who had had a median of 6 syncope episodes in the prior year (median age, 32 years; 73% female). Compared with patients receiving placebo, fewer patients receiving midodrine had at least 1 syncope episode (28 of 66 [42%] vs. 41 of 67 [61%]). The relative risk was 0.69 (95% CI, 0.49 to 0.97; P = 0.035). The absolute risk reduction was 19 percentage points (CI, 2 to 36 percentage points), and the number needed to treat to prevent 1 patient from having syncope was 5.3 (CI, 2.8 to 47.6). The time to first syncope was longer with midodrine (hazard ratio, 0.59 [CI, 0.37 to 0.96]; P = 0.035; log-rank P = 0.031). Adverse effects were similar in both groups. LIMITATION: Small study size, young and healthy patients, relatively short observation period, and high proportion of patients from 1 center. CONCLUSION: Midodrine can reduce the recurrence of syncope in healthy, younger patients with a high syncope burden. PRIMARY FUNDING SOURCE: The Canadian Institutes of Health Research.

Implementation of measures to reduce vasovagal reactions: Donor participation and results.

BACKGROUND: There are several strategies to reduce donor reactions. We report donor participation and reaction rates before and after implementing multiple measures at Canadian Blood Services. STUDY DESIGN AND METHODS: We introduced a structured program of 500 mL of water and a salty snack pre-donation and applied muscle tension (AMT) during donation. Donors were not deferred for out of range blood pressure (BP); however, BP was measured in first time donors. Time on the donation chair post-donation was decreased from 5 to 2 min for repeat donors. We assessed participation rates using our quarterly survey of 10,000 recent donors. We extracted vasovagal reactions with loss of consciousness (LOC) from our operational database and compared pre-implementation (Oct 12,018-March 31,2019) and post-implementation (Oct 12,019-March 31,2020) periods. RESULTS: Survey response rates varied from 11% to 16%. The percentage of donors who drank the water and ate the salty snack increased from 58% to 82% and 44% to 70% over 4 quarters; those performing AMT increased from 24% to 41%. Reactions decreased from 19.07 per 10,000 (744 reactions in 390,123 donations) to 14.04 per 10,000 (537 in 382,382 donations) (p < .0001). No first-time donors with high BP (n = 684) but 5 with low BP (n = 718) had reactions, CI were very large. CONCLUSIONS: Achieving optimal participation was challenging. After implementation of a donor wellness initiative based on best practice, rates of vasovagal reactions with LOC decreased by 25%. A larger dataset is necessary to assess the safety contribution of BP deferrals when other mitigation measures are in place.

Improving the donation experience and reducing venipuncture pain by addressing fears among whole-blood and plasma donors.

BACKGROUND: Fear of blood donation is implicated in vasovagal reactions, donor recruitment, and retention. This study examined the extent to which fear among donors is associated with various donor outcomes in an Australian sample, and whether fear can be addressed on-site to reduce adverse reactions and improve the donation experience. STUDY DESIGN AND METHODS: Six hundred and sixty-four donors (age M = 33.4, SD = 12.7; 55% female) participated in a two-center, pragmatic, parallel group, individually randomized controlled trial. Following donor registration and consent, whole-blood (n = 539) and plasma (n = 125) donors were assigned to one of four Conditions: control; fear assessment; fear assessment + brochure; fear assessment + brochure + tailored conversation focused on any self-reported fear and coping strategies. Post-donation questionnaires assessed the donors' experience including positive support, donor self-efficacy, anxiety, fear, venipuncture pain, and vasovagal reactions. RESULTS: Fear among donors predicted higher venipuncture pain, post-donation anxiety, and vasovagal reactions and remained significant after controlling for other established predictors (i.e., total estimated blood volume, age, sex, and donation experience). Mediational analyses showed that exposure to brochures (with or without the tailored conversation) was associated with less pain, with this effect mediated by donor perceptions of more positive support. Venipuncture pain was also associated with vasovagal reactions, reduced likelihood of return within 6 months, and less satisfaction with the donation experience. CONCLUSION: The current results underline the importance of interventions to address fear among both whole-blood and plasma donors to secure the safety and well-being of donors and the blood supply.

A randomized study of yoga therapy for the prevention of recurrent reflex vasovagal syncope.

AIMS: Vasovagal syncope (VVS) is a common cardiovascular dysautonomic disorder that significantly impacts health and quality of life (QoL). Yoga has been shown to have a positive influence on cardiovascular autonomics. This study assessed the effectiveness of yoga therapy on the recurrence of VVS and QoL. METHODS AND RESULTS: We randomized subjects with recurrent reflex VVS (>3 episodes in the past 1 year) and positive head-up tilt test to guideline-directed therapy (Group 1) or yoga therapy (Group 2). Patients in Group 1 were advised guideline-directed treatment and Group 2 was taught yoga by a certified instructor. The primary endpoint was VVS recurrences and QoL. Between June 2015 and February 2017, 97 highly symptomatic VVS patients were randomized (Group 1: 47 and Group 2: 50). The mean age was 33.1 ± 16.6 years, male:female of 40:57, symptom duration of 17.1 ± 20.7 months, with a mean of 6.4 ± 6.1 syncope episodes. Over a follow-up of 14.3 ± 2.1 months Group 2 had significantly lower syncope burden compared with Group 1 at 3 (0.8 ± 0.9 vs. 1.8 ± 1.4, P < 0.001), 6 (1.0 ± 1.2 vs. 3.4 ± 3.0, P < 0.001), and at 12 months (1.1 ± 0.8 vs. 3.8 ± 3.2, P < 0.001). The Syncope functional score questionnaire was significantly lower in Group 2 compared with Group 1 at 3 (31.4 ± 7.2 vs. 64.1 ± 11.5, P < 0.001), 6 (26.4 ± 6.3 vs. 61.4 ± 10.7, P < 0.001), and 12 months (22.2 ± 4.7 vs. 68.3 ± 11.4, P < 0.001). CONCLUSION: For patients with recurrent VVS, guided yoga therapy is superior to conventional therapy in reducing symptom burden and improving QoL.

Permanent pacing for recurrent vasovagal syncope: New answers or just more questions?

Vasovagal syncope (VVS) is a clinical condition related to bradycardia (cardioinhibitory response) and/or hypotension (vasodepressor response), likely mediated by parasympathetic overactivity and sympathetic withdrawal. Although clinical presentation is usually related to a self-limited event, frequent episodes or events without prodrome might be debilitating. There are limited medical therapies proven effective in randomized clinical trials. In patients not responsive to standard therapy, permanent pacemaker therapy may be suggested. However, the role of cardiac pacing for the prevention of syncope recurrences remains controversial due to difficulties to exclude potential role of the vasodepressor component during the episode.

A randomized controlled trial of a tablet-based intervention to address predonation fears among high school donors.

BACKGROUND: Prior studies have shown donation-related fear to be associated with decreased donor confidence and an increased risk for vasovagal reactions. This study examined the effects of a predonation intervention that provided fearful donors with suggestions for coping. STUDY DESIGN AND METHODS: Using a tablet-based application, high school donors (49.4% female) answered a question regarding their fear of having blood drawn. Those who reported fear were randomly assigned to either a control (n = 930) or an intervention (n = 911) group. Donors in the control group rated their confidence in dealing with their fear and then donated as usual. Donors in the intervention group received a brief audiovisual presentation on coping strategies, rated their confidence, and then donated as usual. RESULTS: A higher proportion of fearful versus nonfearful donors experienced a vasovagal reaction, even after controlling for other demographic and health predictors (OR, 2.3; 95% CI, 1.655-3.185, p < 0.001). Fearful donors who received the intervention reported greater confidence than controls, but the proportion of vasovagal reactions did not differ significantly between the intervention (6.1%) and control (6.8%) groups. CONCLUSION: Although the current tablet-based intervention may have some psychological benefit in that it was associated with greater donor confidence, the observed effect was small and did not translate into a lower risk for vasovagal reactions. However, greater confidence among young donors may lead to an increased willingness to donate again-a potential outcome that we will revisit among these donors as part of a planned 2-year follow-up.

Reduced risk of vasovagal reactions in Australian whole blood donors after national implementation of applied muscle tension and water loading.

BACKGROUND: A new national donor safety initiative was introduced in Australia in 2018, which aimed to encourage all whole blood donors to water load and to use applied muscle tension. This study evaluated the effect of this initiative on the rate of vasovagal reactions (VVR). STUDY DESIGN AND METHODS: Routinely collected data were used to identify whole blood donations and any associated VVRs before (n = 167,056 donations) and after implementation (n = 215,572 donations). Multivariate logistic regression analyses were performed to evaluate the differences in VVR rates. RESULTS: The total rate of VVRs declined from 22.5 per 1000 donations to 20.6 per 1000 donations after implementation, a reduction of 8% (p < 0.001). The rate of presyncopal reactions decreased by 8% in new donors and 12% in repeat donors. No impact was observed on the rate of syncope in any of the groups. The multivariate logistic regression analysis demonstrated the odds of experiencing a presyncopal reaction was reduced by 13% following implementation, with no significant effects on syncope. CONCLUSION: The findings of this study support the use of water loading and applied muscle tension in routine whole blood collection to reduce the incidence of VVRs.

Frequency of injuries associated with syncope in the prevention of syncope trials.

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

Respiration and applied tension strategies to reduce vasovagal reactions to blood donation: A randomized controlled trial.

BACKGROUND: Whether produced by breathing too fast or too deeply, hyperventilation is common in stressful situations and may contribute to blood donation-related vasovagal symptoms. The effects of some previously tested interventions for vasovagal symptoms, for example, applied tension (AT), may be related to reduction of hyperventilation. More targeted breathing techniques might be useful. STUDY DESIGN AND METHODS: This was a randomized controlled trial comparing the effects of AT, a slow, shallow "anti-hyperventilation" breathing technique previously tested in phobic individuals (respiration control [RESP]), the combination of AT and RESP, and no intervention on blood donors participating in university clinics. A total of 547 eligible donors were assigned randomly to one of these four groups. Observational, self-report, and physiologic measures (primarily via respiratory capnometry) were obtained. RESULTS: Although both RESP and AT had some positive impact on blood donation outcome, the effects of RESP were more numerous, albeit limited primarily to donors who had less general fear of medical procedures. For example, lower-fear donors assigned to practice RESP had significantly lower Blood Donation Reaction Inventory scores and were significantly less likely to require treatment for symptoms than no-treatment individuals. In general, RESP led to a significant decrease in respiration rate, though it did not influence end-tidal CO2 , a more precise measure of hyperventilation. CONCLUSION: While the mechanisms remain somewhat unclear and the interventions did not benefit more fearful, higher-risk donors, respiration control is a promising additional approach to reducing vasovagal symptoms.