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.

Ankle reflex and neurological symptom score: a primary level screening method for diabetic peripheral neuropathy.

Herein, we aimed to develop an easily available and efficient screening method for diabetic peripheral neuropathy (DPN) suitable for primary care settings, emphasizing simplicity, speed, and accuracy. Nerve conduction studies were conducted on 214 patients with diabetes, encompassing the outcomes of five distinct assessments: diabetic neuropathy symptom (DNS), vibration perception threshold (VPT), and nerve screening. The diagnostic accuracy of the VPT and nerve screening was evaluated by comparing them with that of the nerve conduction study. To assess diagnostic efficacy, various combinations were examined, including DNS combined with VPT, pain, temperature, touch, and ankle reflex. The diagnostic performance of DNS was superior to that of the five neurological screening items and VPT, with sensitivity, specificity, and accuracy of 0.68, 0.81, and 0.73, respectively. Among the two combined methods, "DNS + ankle reflex" was identified as having the highest diagnostic value, with an area under the curve, a sensitivity, a specificity, and an accuracy of 0.81, 0.89, 0.70, and 0.80, respectively. Furthermore, a combination of "DNS + ankle reflex + touch + pain + VPT" achieved the best performance among the five combinations, with an area under the curve, sensitivity, specificity, and accuracy of 0.85, 0.93, 0.68, and 0.81, respectively. The combination of DNS, ankle reflex, touch, pain, and VPT methods showed the highest diagnostic value for DPN. However, considering factors including accuracy, time, and economic cost, we recommend using a simpler combination of DNS and ankle reflex for large-scale screening of patients with DPN.

Neural discharge of muscle afferents and pressor response to mechanical stimulation are associated with muscle deformation velocity in rats.

Skeletal muscle reflexes play a crucial role in determining the magnitude of the cardiovascular response to exercise. However, evidence supporting an association between the magnitude of the pressor response and the velocity of muscle deformation has remained to be elucidated. Thus, we investigated the impact of different muscle deformation rates on the neural discharge of muscle afferents and pressor and sympathetic responses in Sprague-Dawley rats. In an ex vivo muscle-nerve preparation, action potentials elicited by sinusoidal mechanical stimuli (137 mN) at different frequencies (0.01, 0.05, 0.1, 0.2, and 0.25 Hz) were recorded in mechanosensitive group III and IV fibers. The afferent response magnitude to sine-wave stimulation significantly varied at different frequencies (ANOVA, P = 0.01). Specifically, as compared with 0.01 Hz (0.83 ± 0.96 spikes/s), the response magnitudes were significantly greater at 0.20 Hz (4.07 ± 5.04 spikes/s, P = 0.031) and 0.25 Hz (4.91 ± 5.30 spikes/s, P = 0.014). In an in vivo decerebrated rat preparation, renal sympathetic nerve activity (RSNA) and mean arterial pressure (MAP) responses to passive stretch (1 kg) of hindlimb skeletal muscle at different velocities of loading (slow, medium, and fast) were measured. Pressor responses to passive stretch were significantly associated with the velocity of muscle deformation (ANOVA, P < 0.001). The MAP response to fast stretch (Δ 56 ± 12 mmHg) was greater than slow (Δ 33 ± 11 mmHg, P = 0.006) or medium (Δ 30 ± 11 mmHg, P < 0.001) stretch. Likewise, the RSNA response was related to deformation velocity (ANOVA, P = 0.024). These findings suggest that the muscle neural afferent discharge and the cardiovascular response to mechanical stimulation are associated with muscle deformation velocity.

Evolution from a first clinical demyelinating event to multiple sclerosis in the REFLEX trial: Regional susceptibility in the conversion to multiple sclerosis at disease onset and its amenability to subcutaneous interferon beta-1a.

BACKGROUND AND PURPOSE: In the REFLEX trial (ClinicalTrials.gov identifier: NCT00404352), patients with a first clinical demyelinating event (FCDE) displayed significantly delayed onset of multiple sclerosis (MS; McDonald criteria) when treated with subcutaneous interferon beta-1a (sc IFN ß-1a) versus placebo. This post hoc analysis evaluated the effect of sc IFN ß-1a on spatio-temporal evolution of disease activity, assessed by changes in T2 lesion distribution, in specific brain regions of such patients and its relationship with conversion to MS. METHODS: Post hoc analysis of baseline and 24-month magnetic resonance imaging data from FCDE patients who received sc IFN ß-1a 44 µg once or three times weekly, or placebo in the REFLEX trial. Patients were grouped according to McDonald MS status (converter/non-converter) or treatment (sc IFN ß-1a/placebo). For each patient group, a baseline lesion probability map (LPM) and longitudinal new/enlarging and shrinking/disappearing LPMs were created. Lesion location/frequency of lesion occurrence were assessed in the white matter. RESULTS: At Month 24, lesion frequency was significantly higher in the anterior thalamic radiation (ATR) and corticospinal tract (CST) of converters versus non-converters (p < 0.05). Additionally, the overall distribution of new/enlarging lesions across the brain at Month 24 was similar in placebo- and sc IFN ß-1a-treated patients (ratio: 0.95). Patients treated with sc IFN ß-1a versus placebo showed significantly lower new lesion frequency in specific brain regions (cluster corrected): ATR (p = 0.025), superior longitudinal fasciculus (p = 0.042), CST (p = 0.048), and inferior longitudinal fasciculus (p = 0.048). CONCLUSIONS: T2 lesion distribution in specific brain locations predict conversion to McDonald MS and show significantly reduced new lesion occurrence after treatment with sc IFN ß-1a in an FCDE population.

Cardiac pacing in severe recurrent reflex syncope and tilt-induced asystole.

AIM: The benefit of cardiac pacing in patients with severe recurrent reflex syncope and asystole induced by tilt testing has not been established. The usefulness of tilt-table test to select candidates for cardiac pacing is controversial. METHODS AND RESULTS: We randomly assigned patients aged 40 years or older who had at least two episodes of unpredictable severe reflex syncope during the last year and a tilt-induced syncope with an asystolic pause longer than 3 s, to receive either an active (pacing ON; 63 patients) or an inactive (pacing OFF; 64 patients) dual-chamber pacemaker with closed loop stimulation (CLS). The primary endpoint was the time to first recurrence of syncope. Patients and independent outcome assessors were blinded to the assigned treatment. After a median follow-up of 11.2 months, syncope occurred in significantly fewer patients in the pacing group than in the control group [10 (16%) vs. 34 (53%); hazard ratio, 0.23; P = 0.00005]. The estimated syncope recurrence rate at 1 year was 19% (pacing) and 53% (control) and at 2 years, 22% (pacing) and 68% (control). A combined endpoint of syncope or presyncope occurred in significantly fewer patients in the pacing group [23 (37%) vs. 40 (63%); hazard ratio, 0.44; P = 0.002]. Minor device-related adverse events were reported in five patients (4%). CONCLUSION: In patients aged 40 years or older, affected by severe recurrent reflex syncope and tilt-induced asystole, dual-chamber pacemaker with CLS is highly effective in reducing the recurrences of syncope. Our findings support the inclusion of tilt testing as a useful method to select candidates for cardiac pacing. STUDY REGISTRATION: ClinicalTrials.gov identifier NCT02324920, Eudamed number CIV-05-013546.

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.

Effects of neurorehabilitation with and without dry needling technique on muscle thickness, reflex torque, spasticity and functional performance in chronic ischemic stroke patients with spastic upper extremity muscles: a blinded randomized sham-controlled clinical trial.

PURPOSE: Evaluation the effects of dry needling on sonographic, biomechanical and functional parameters of spastic upper extremity muscles. METHODS: Twenty-four patients (35-65 years) with spastic hand were randomly allocated into two equal groups: intervention and sham-controlled groups. The treatment protocol was 12-sessions neurorehabilitation for both groups and 4-sessions dry needling or sham-needling for the intervention group and sham-controlled group respectively on wrist and fingers flexor muscles. The outcomes were muscle thickness, spasticity, upper extremity motor function, hand dexterity and reflex torque which were assessed before, after the 12th session, and after one-month follow-up by a blinded assessor. RESULTS: The analysis showed that there was a significant reduction in muscle thickness, spasticity and reflex torque and a significant increment in motor function and dexterity in both groups after treatment (p < 0.01). However, these changes were significantly higher in the intervention group (p < 0.01) except for spasticity. Moreover, a significant improvement was seen in all outcomes measured one-month after the end of the treatment in the intervention group (p < 0.01). CONCLUSIONS: Dry needling plus neurorehabilitation could decrease muscle thickness, spasticity and reflex torque and improve upper-extremity motor performance and dexterity in chronic stroke patients. These changes were lasted one-month after treatment.Trial Registration Number: IRCT20200904048609N1IMPLICATION FOR REHABILITATIONUpper extremity spasticity is one of the stroke consequences which interfere with motor function and dexterity of patient hand in activity of daily livingApplying the dry needling accompanied with neurorehabilitation program in post-stroke patients with muscle spasticity can reduce the muscle thickness, spasticity and reflex torque and improve upper extremity functions.

The effect of intravenous lidocaine on laryngeal and respiratory reflex responses in anaesthetised children*.

We studied the effect of intravenous lidocaine on laryngeal and respiratory reflex responses in children anaesthetised with sevoflurane. We tested the hypothesis that the incidence of laryngospasm evoked by laryngeal stimulation is temporarily diminished after the administration of lidocaine. Forty children, aged between 25 and 84months, were anaesthetised with sevoflurane and breathed spontaneously through a laryngeal mask airway. Respiratory reflex responses were elicited by spraying distilled water onto the laryngeal mucosa at three time intervals: (i) before lidocaine was administered (baseline); (ii) at 2min and (iii) at 10min following the intravenous administration of a bolus of lidocaine 2mg.kg(-1) . A blinded reviewer assessed the evoked responses. The incidence of laryngospasm was reduced from 38% at baseline to 15% 2min after lidocaine administration (p<0.02) and 18% 10min after lidocaine administration (p=0.10). We conclude that intravenous lidocaine significantly reduced the incidence of laryngospasm but that the effect was short-lived.

Artificial Proprioceptive Reflex Warning Using EMG in Advanced Driving Assistance System.

A frequent cause of auto accidents is disregarding the proximal traffic of an ego-vehicle during lane changing. Presumably, in a split-second-decision situation we may prevent an accident by predicting the intention of a driver before her action onset using the neural signals data, meanwhile building the perception of surroundings of a vehicle using optical sensors. The prediction of an intended action fused with the perception can generate an instantaneous signal that may replenish the driver's ignorance about the surroundings. This study examines electromyography (EMG) signals to predict intention of a driver along perception building stack of an autonomous driving system (ADS) in building an advanced driving assistant system (ADAS). EMG are classified into left-turn and right-turn intended actions and lanes and object detection with camera and Lidar are used to detect vehicles approaching from behind. A warning issued before the action onset, can alert a driver and may save her from a fatal accident. The use of neural signals for intended action prediction is a novel addition to camera, radar and Lidar based ADAS systems. Furthermore, the study demonstrates efficacy of the proposed idea with experiments designed to classify online and offline EMG data in real-world settings with computation time and the latency of communicated warnings.

[Laboratory testing for anemia in primary care: reflex testing, reflecting and algorithms?] / Anemiediagnostiek in de eerste lijn.

This commentary discusses the prevalence and causes of anemia in primary care in the Netherlands and the role of laboratory diagnostics in determining the cause of anemia. There are indications that guidelines in primary care regarding anemia are insufficiently followed; there are also indications that the correct laboratory measurements are requested too limited (under-diagnosis). A possible solution lies in the introduction of reflective testing, in which the laboratory specialist has additional diagnostic laboratory tests performed on the basis of the laboratory results and specific characteristics of the patient. Reflective testing is in contrast to reflex testing; in reflex testing, laboratory measurements are added automatically using a simple flowchart. In the future, Artificial Intelligence solutions could play a role in determining the most optimal laboratory diagnostic strategy for the diagnosis of anemia in primary care.

Dysphoric milk ejection reflex (D-MER) and its implications for mental health nursing.

Dysphoric milk ejection reflect (D-MER) is a dysphoria which women may experience within seconds of commencing breastfeeding. It is only recently gaining recognition in the academic literature and may have important implications for breastfeeding continuation, differential diagnosis and perinatal mental health. This perspective piece introduces the topic, sets out the physiological processes underpinning the experience and outlines why increased awareness of D-MER is important for the profession of mental health nursing.

Point/counterpoint: Arterial blood pressure response to exercise does relate to exercise-induced improvement in cognitive function.

Exercise is a beneficial intervention to prevent cognitive dysfunction. However, an optimal exercise prescription for preventing dementia has not been established because the physiological mechanism(s) of exercise-induced improvements in cognitive function remains unclear. Interestingly, our recent study demonstrated that individuals with a higher exercise pressor response exhibit less exercise-induced cognitive improvement, suggesting that individual differences in cardiovascular responses to exercise or its associated physiological factors, may be related to exercise-induced alterations in cognitive function. Therefore, consideration of individual cardiovascular responses is warranted to develop appropriate exercise prescriptions for a given individual to prevent cognitive dysfunction.

Improving Red Reflex Screening in a Level III NICU Through a Quality Improvement-based Approach.

BACKGROUND: Red reflex is a routine part of newborn examination in most high-income countries. It is an inexpensive, noninvasive method of detecting serious ocular abnormalities like cataracts, retinoblastoma, vitreous masses, etc. The American Academy of Pediatrics recommends red reflex examination before discharge from newborn nursery. However, the current rate of red reflex examination in the NICUs in the United States is unknown. We noted a low rate of documentation (19%) in our level III NICU, prompting us to initiate this quality improvement project to improve this rate. METHODS: We created a key-driver diagram and summarized possible interventions to achieve our aim to increase the documentation rate to >80%. We implemented various interventions over 4 plan-do-study-act cycles. Over 19 months, we educated the nurses and the providers regarding the importance of red reflex assessment, placed visual reminders to check red reflex, implemented discharge checklist for the residents, and improved the accessibility to ophthalmoscope. RESULTS: Infants discharged from our NICU during a 25-month period included 1168 infants who an ophthalmologist did not formally examine. The rate of red reflex documentation improved significantly from a baseline of 19% (6 months before the first plan-do-study-act cycle) to 89.5% (during the 19-month intervention period). One abnormal red reflex was detected during this study. CONCLUSIONS: Implementation of this project has led to a culture change at our institution, which will help prevent us from missing the diagnosis of serious visual abnormalities in the future.

Assessment of scheduling for patients referred for an abnormal red reflex.

Scheduling lag time is the time between the date of an appointment and the date an appointment was created in the scheduling system. We sought to determine the scheduling lag time in a pediatric ophthalmology clinic for children <8 years of age, referred by a primary care provider for an abnormal red reflex (ARR), cataract, leukocoria, or retinoblastoma. The median scheduling lag time was 1.8 days (IQR, 0.8-5.0). Of the 106 total appointments, 89 (84%) were completed as scheduled, 12 (11%) were canceled, and 5 (5%) were no-shows. Ten patients (12%) were never seen. There was a shorter scheduling lag time for completed visits (median, 1.1 days; IQR, 0.2-4.0) than canceled visits (median, 12.0 days; IQR, 3.1-48.5; P < 0.001). Monitoring of the scheduling lag time for urgent referrals may be a metric for quality improvement in pediatric ophthalmology.

Cough in the elderly: a novel strategy for preventing aspiration pneumonia.

Management of cough in the elderly with a deteriorated physical and mental status has received little focus. Since an aged population is rapidly increasing in developed countries, the research in this population are warranted. Cough reflex sensitivity in the elderly was shown to be hypersensitive, normosensitive and hyposensitive. The hypersensitive cough reflex is mostly due to gastro-esophageal reflux in nursing home patients. Impaired cough reflex sensitivity is assumed to play a crucial role in the development of pneumonia in the elderly. A marked depression of cough reflex sensitivity is reported in elderly patients with aspiration pneumonia. The impairment of the cough reflex in patients with aspiration pneumonia can involve both cortical facilitatory pathways for cough and medullary reflex pathways. We found the urge-to-cough in patients with aspiration pneumonia was also down-regulated, suggesting the involvement of supramedullary dysfunction in the etiology of aspiration pneumonia in the elderly. In order to prevent aspiration pneumonia in the elderly, restoration of cough reflex sensitivity is essential. We found several methods to restore cough reflex sensitivity in the elderly. They also improved the swallowing reflex, another important airway protective reflex, in the elderly. In the treatment of aspiration pneumonia, one of the most challenging steps is the start of eating for patients who usually fast at the time of hospitalization. By combining the methods to restore the cough reflex sensitivity and swallowing reflex, we developed a protocol to start eating in the elderly patients with aspiration pneumonia. Using the protocol, we reduced the incidence of re-aspiration due to start of eating in patients with aspiration pneumonia to one third of the patients without the protocol.

Voluntary and reflex cough and the expiration reflex; implications for aspiration after stroke.

Aspiration is a common result of stroke, and may lead to lung infections and pneumonia. Cough may prevent this aspiration and thus prevent the pneumonia. We review the four types of cough usually used to assess aspiration risk: voluntary cough (VC), reflex cough (RC), the laryngeal expiration reflex (LER), and cough on swallow (CoS). VC is easy to test but starts with an inspiration that may cause aspiration, and is controlled by cortico-brainstem pathways that may not be involved in influencing aspiration. RC also starts with an inspiration, and requires instrumental intervention, but is more relevant to protecting the lungs. The LER starts with an expiration, so is 'anti-aspiration', and is easy to test, but its neural mechanisms have not been fully analysed. CoS can be tested at the same time as direct observations of aspiration, but little is known about its neural mechanisms. Each method has its advocates, and the purpose of the review is to discuss how each may be applied and how the information from each may be assessed and valued.

Sensory stimulation to improve swallowing reflex and prevent aspiration pneumonia in elderly dysphagic people.

Morbidity and mortality from aspiration pneumonia continues to be a major health problem in the elderly. A swallowing disorder, such as a delayed triggering of the swallowing reflex, exists in patients with aspiration pneumonia. We found that the swallowing reflex in elderly people was temperature-sensitive. The swallowing reflex was delayed when the temperature of the food was close to body temperature. The actual swallowing time shortened when the temperature difference increases. The improvement of swallowing reflex by temperature stimuli could be mediated by the temperature-sensitive transient receptor potential (TRP) channel. The administration of a pastille with capsaicin as an agonist stimulus of TRPV1, a warm-temperature receptor, decreased the delay in swallowing reflex. Food with menthol, an agonist of TRPM8, a cold-temperature receptor, also decreased the delay in swallowing reflex. Olfactory stimulation such as black pepper was useful to improve the swallowing reflex for people with low activity of daily living (ADL) levels or with decreased consciousness. Oral care also shortened the latent time of swallowing reflex presumably due to stimulating the nociception of the oral cavity. A combination of these sensory stimuli may improve the swallowing disorders and prevent aspiration pneumonia.

The muscle engram: the reflex that limits conventional occlusal treatment.

The engram (the masticatory "muscle memory") is shown to be a conditionable reflex whose muscle conditioning lasts less than two minutes, far shorter than previously thought. This reflex, reinforced and stored in the masticatory muscles at every swallow, adjusts masticatory muscle activity to guide the lower arch unerringly into its ICP. These muscle adjustments compensate for the continually changing intemal and external factors that affect the mandible's entry into the ICP. A simple quick experiment described in this article isolates the engram, enabling the reader to see its action clearly for the first time. It is urged that every reader perform this experiment. This experiment shows how the engram, by hiding the masticatory muscles' reaction (the hit-and-slide), limits the success of the therapist in achieving occlusion-muscle compatibility. This finding has major clinical implications. It means that, as regards the muscle aspect of treating occlusion, the dentist treating occlusion conventionally is working blind, a situation the neuromuscular school of occlusal thought seeks to correct. The controversy over occlusion continues.

Spasm of near reflex: a comprehensive management protocol and treatment outcomes.

PURPOSE: To report a consolidated management protocol for patients with spasm of near reflex (SNR), including classification of cases as mild, moderate, and severe based on treatment outcomes. METHODS: Patients with SNR treated at a single institution between August 2016 and November 2018 were included. Management of SNR included modified optical fogging, vision therapy, and pharmacological intervention (cyclopentolate eye drops and, if required, atropine eye drops). Outcome measures were visual acuity (20/25 or better) and refractive error (reduction of excessive myopia). RESULTS: Of 1,306 patients examined during the study period, 66 were diagnosed with SNR, yielding a prevalence of 5% among first-time patients visiting our binocular vision and orthoptics clinic. Of the 45 patients recruited for this study (mean age, 14 ± 5 years; 24 males), all three near-triad components were involved in 11 patients (24%), only the accommodation component in 32 (71%), and only the convergence component in 2 (4%). SNR was relieved in the first post-cyclopentolate refraction visit or with the modified optical fogging technique in 29 patients (66%; mild SNR) and with one-time usage of atropine eyedrops in 10 patients (22%; moderate SNR). In 6 patients (13%), atropine was continued long-term (severe SNR). Of 15 patients with long-term follow-up (1 year), 11 (73%) had persistent relief of SNR. CONCLUSIONS: In our study cohort, SNR with accommodation component was the most common and could be largely relaxed through a one-time use of cycloplegic eye drops and optical intervention. Only severe forms of SNR may require extended use of strong cycloplegics.

Heart rate distribution in paced and non-paced patients with severe recurrent reflex syncope and tilt-induced asystole: Findings from the BIOSync CLS study.

BACKGROUND: Undiagnosed sinus or atrioventricular node dysfunction may bias estimation of the real efficacy of cardiac pacing in preventing vasovagal reflex syncope. We assessed this hypothesis in the BIOSync CLS trial which showed that dual-chamber pacing with closed loop stimulation (CLS) remarkably reduced recurrences of syncope. METHODS AND RESULTS: In the study patients aged 40 years or older with ≥2 episodes of loss of consciousness in the last year and an asystolic response to Tilt-Table test were randomized to pacing ON (DDD-CLS mode) or pacing OFF (ODO mode). We utilized the available pacemaker diagnostic data in a total of 103 patients (52 pacing ON, 51 pacing OFF) to generate cumulative distribution charts for heart rate (HR) and percentage of pacing. At 12 months, we did not find evidence of suspected sinus or atrioventricular node dysfunction. Beats were similarly distributed between groups (p = 0.96), with an average HR of 76 ± 8 bpm (pacing ON) versus 77 ± 7 bpm (pacing OFF). In the active group, the median percentage of atrial and ventricular pacing was 47% and 0%, respectively. Intolerance to high pacing rates was reported in only one patient (1.6%) and was easily resolved by reprogramming the maximum CLS pacing rate. CONCLUSIONS: We did not find evidence of suspected sinus or atrioventricular node dysfunction in the BIOSync CLS patients. The benefit of pacing should be ascribed to pacing prevention of pure vasovagal episodes. CLS algorithm modulated pacing rates over a wide frequency range, consistently competing with sinus node.