Head-up Tilt Table Research Articles

Postprandial hypotension is more common than orthostatic hypotension in older adults with dementia with lewy bodies: a cross-sectional study

Cardiovascular autonomic dysfunction is one of the supportive clinical features in dementia with Lewy bodies (DLB). This study aimed to investigate the frequency of postural and postprandial hypotension in people with DLB. The study group comprised 125 patients with DLB (76 females; mean age 78.4 ± 7.1 years) and 122 controls (88 females; mean age 74.4 ± 6.9 years). Postprandial blood pressure changes were assessed by ambulatory 24-hour blood pressure monitorization. Postural blood pressure changes were assessed via the head-up tilt table test. The frequency of postprandial hypotension (PPH) and orthostatic hypotension (OH) was higher in patients with DLB compared to controls (89.4% vs 51.7%; p < 0.001, and 45.5% vs 27.9%; p = 0.004, respectively) whereas the frequency of supine hypertension (SH), and orthostatic hypertension (OHT) was similar. However, SH in non-hypertensive participants was higher in DLB patients than in controls (48.9%, 25.7%; p = 0.035). PPH and OH were independently associated with a diagnosis of DLB (odds ratio [OR]:10.26 confidence interval [CI]%95 3.02–34.82; p < 0.001, and OR:2.22 CI%95 1.2–4.12; p = 0.012, respectively) after adjustment for age, number of medications, use of anti-psychotics drugs, angiotensin receptor blockers, and beta blockers. In conclusion, the study demonstrated that PPH was the most common finding of cardiovascular autonomic dysfunction, followed by OH and SH in older patients with DLB. Given the potential complications of postural blood pressure changes and PPH in such patients, cardiovascular autonomic dysfunction should be evaluated in patients with DLB.

Evaluation of a Short-Duration Head-Up Tilt Table Test Protocol and its Role in Contemporary Clinical Practice

Evaluation of a Short-Duration Head-Up Tilt Table Test Protocol and its Role in Contemporary Clinical Practice

Diagnostic yield of head-up tilt table test in hypertrophic cardiomyopathy and unexplained syncope: the knot does not seem to be unraveling.

Conflicting results have been published considering the diagnostic performance of head-up tilt test (HUTT) in patients with hypertrophic cardiomyopathy (HCM). We aimed to conduct a meta-analysis to evaluate the diagnostic value of HUTT in the evaluation of unexplained syncope in patients with HCM. We performed a structured systematic database search using the following keywords: hypertrophic cardiomyopathy, syncope, unexplained syncope, head-up tilt test, tilt table test, tilt testing, orthostatic stress, autonomic function, autonomic response. Studies in which the HUTT was used to define autonomic dysfunction in patients with syncope at baseline or without syncope were included in the final analysis. A total of 252 HCM patients from 6 studies (159 patients without a history of syncope and 93 with a history of syncope, respectively) were evaluated. HUTT was positive in 50 (19.84%) of 252 patients (in 21 of 93 patients (22.58%) with a history of syncope and in 29 of 159 patients (18.24%) without a history of syncope, respectively). The pooled total sensitivity and specificity of the HUTT for detecting syncope were 22.1% (14.8-35.1%) and 83.6% (73.2-91.6%), respectively. The summary receiver operator curve showed that HUTT had an only modest discriminative ability for syncope with an area under the curve value of 0.565 (0.246-0.794). Although HUTT has significant limitations in diagnosis of unexplained syncope in patients with HCM, it may still be used to determine hypotensive susceptibility. Other autonomic tests can be used in diagnostic workflow in this population.

Serotonin and vasovagal syncope.

The goal of this manuscript was to review the biological and clinical evidence that serotonin neurotransmission might play an important role in the physiology and treatment of vasovagal syncope. The authors reviewed PubMed and handsearches of secondary sources for papers related to the Bezold-Jarisch reflex and serotonin, the plausible involvement of the Bezold-Jarisch reflex in vasovagal syncope, and three lines of clinical evidence involving serotonin and the syncope. The Bezold-Jarisch reflex was first described following the infusion of veratrum alkaloids into animals in the 19th century. The reflex is triggered by serotonin stimulation chemoreceptors and mechanoreceptors in the the left ventricle. The afferent component of the reflex is carried by unmyelinated type C vagal nerve fibers, which results in parasympathetic efferent stimulation that causes bradycardia. The similarity of the combination of hypotension and bradycardia in the Bezold-Jarisch reflex and in vasovagal syncope led to the suggestion that the reflex was the cause of the syndrome. Three lines of evidence implicate the serotonin 5HT3 receptors in the heart in the reflex. There is genetic and physiologic evidence for the serotonin 5HT1A and 5HT3 receptors and the serotonin reuptake transporter (SERT). Acute blockade of SERT induces vasovagal syncope in humans undergoing head-up tilt table testing, and SERT inhibition reduces hypotension and bradycardia during spinal anaesthesia. Finally, three randomized clinical trials of SERT inhibitors uniformly reported that they significantly reduce the likelihood of vasovagal syncope recurrences. Multiple lines of evidence implicate serotonin neurotransmission in the cause of vasovagal syncope.

Ocular Vestibular-Evoked Myogenic Potential Assists in the Differentiation of Multiple System Atrophy From Parkinson's Disease.

Vestibular-evoked myogenic potentials (VEMPs) can help in assessing otolithic neural pathway in the brainstem, which may also contribute to the cardiovascular autonomic function. Parkinson's disease (PD) is associated with altered VEMP responses; however, the associations between VEMP abnormalities and multiple system atrophy (MSA) remain unknown. Therefore, we compared the extent of otolith dysfunction using ocular (oVEMP) and cervical VEMPs between patients with MSA and PD. We analyzed the clinical features, VEMP, and head-up tilt table test (HUT) findings using the Finometer in 24 patients with MSA and 52 with de novo PD who had undergone neurotologic evaluation at a referral-based university hospital in South Korea from January 2021 to March 2023. MSA was associated with bilateral oVEMP abnormalities (odds ratio [95% confidence interval] = 9.19 [1.77-47.76], p = 0.008). The n1-p1 amplitude was negatively correlated with the Unified Multiple System Atrophy Rating Scale I-II score in patients with MSA (r = -0.571, p = 0.033), whereas it did not correlate with the Movement Disorder Society-Unified Parkinson's Disease Rating Scale-III score in patients with PD (r = -0.051, p = 0.687). The n1 latency was negatively correlated with maximum changes in systolic blood pressure within 15 s during HUT in patients with PD (r = -0.335, p = 0.040) but not in those with MSA (r = 0.277, p = 0.299). Bilaterally abnormal oVEMP responses may indicate the extent of brainstem dysfunction in MSA. oVEMP reflects the integrity of otolith-autonomic interplay, reliably assists in differentiating between MSA and PD, and helps infer clinical decline.

Deep abdominal breathing reduces heart rate and symptoms during orthostatic challenge in patients with postural orthostatic tachycardia syndrome.

This study investigated the effects of deep abdominal breathing on cardiovascular parameters and symptoms in patients with postural orthostatic tachycardia syndrome (POTS) during head-up tilt-table (HUT) challenge. Thirty POTS patients completed two consecutive rounds of 10-min HUT in a crossover design. One round was HUT without intervention, and one round combined the HUT with deep breathing at a rate of 6 breaths/min. Cardiovascular parameters, including mean blood pressure and maximum and mean heart rate (HR), were measured supine and standing. Symptoms were assessed using the Vanderbilt Orthostatic Symptom Score (VOSS). During the breathing technique, the mean HR increase was -7.35 bpm (95% confidence interval [CI] = -11.71 to -2.98), and the maximum HR increase was -6.27 bpm (95% CI = -11.85 to -0.68, p = 0.041), significantly lower compared to normal breathing. Additionally, improvements were observed in all absolute cardiovascular parameters during standing, with VOSS symptoms simultaneously and significantly decreasing by -5.38 (95% CI = -10.43 to -0.36). Slow deep abdominal breathing can act as a simple technique to reduce the standing HR increase upon HUT in patients with POTS. This suggests that modulation of the cardiopulmonary neurocircuits and the respiratory pump may reduce HR increase and symptoms in patients with POTS. The findings of this study highlight the use of a safe, zero-cost, and simple behavioral tool to suggest to POTS patients for symptom relief apart from standard treatment. The observed improvements in cardiovascular parameters and symptoms offer a promising therapeutic approach for patients in times of inadequate treatment options.

Decreased heart rate variability in sympathetic dominant states in Parkinson's disease and isolated REM sleep behavior disorder

IntroductionParkinson's disease (PD) presents with decreased heart rate variability (HRV) from its early stages. However, most of its evidence originates from HRV measurements in parasympathetic dominant states. In this study, we aimed to examine whether HRV in sympathetic dominant states during the head-up tilt table test (HUT) serves as a marker of autonomic dysfunction in PD and isolated REM sleep behavior disorder (iRBD). MethodsWe retrospectively assessed 102 patients with PD, 10 patients with iRBD, and 43 healthy controls. We then measured the coefficient of variation of RR intervals as an HRV parameter in sympathetic dominant states (CVRR-S) and parasympathetic dominant states (CVRR-P). Furthermore, we evaluated parameters of cardiac autonomic function, including HUT and the heart-to-mediastinum (H/M) ratio of cardiac metaiodobenzylguanidine scintigraphy. ResultsPatients with iRBD and PD at Hoehn and Yahr stage I exhibited a significantly decreased CVRR-S compared to healthy controls (controls vs. iRBD vs. PD; 1.82 ± 0.64 % vs. 1.13 ± 0.41 % vs. 1.15 ± 0.51 %, p < 0.001), although no further deterioration was observed in PD at more severe Hoehn and Yahr stages. CVRR-S showed a significant correlation with the H/M ratio in PD (r = 0.51, p < 0.001). Additionally, receiver operating characteristic (ROC) analysis revealed a larger area under the ROC curve in CVRR-S compared to that in CVRR-P for discriminating PD or iRBD from healthy controls. ConclusionHRV in sympathetic dominant states shows the potential to be a marker of autonomic dysfunction in iRBD and early-stage PD, aiding in early diagnosis and patient stratification.

The Head-Up Tilt Table Test as a Measure of Autonomic Functioning among Patients with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome.

Individuals with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) often experience autonomic symptoms. In the present study, we evaluated 193 adults seeking treatment for ME/CFS, who were recruited from an outpatient clinic. The participants completed a head-up tilt table test to assess two common types of orthostatic intolerance, namely, postural orthostatic tachycardia syndrome (POTS) and orthostatic hypotension (OH). During the tilt test, 32.5% of the participants demonstrated POTS or OH. The participants with either of these two common types of orthostatic intolerance were found to have more problems with sleep and post-exertional malaise as assessed by the DePaul Symptom Questionnaire; these patients also reported more physical and health function limitations. The implications of the findings are discussed.

Postural orthostatic tachycardia syndrome and other autonomic dysfunctions following COVID-19: Incidence, characteristics, and associated factors.

Long-COVID syndrome has become a new health concern. Many major clinical centers have experienced more patients with symptoms suggestive of autonomic dysfunction, especially postural orthostatic tachycardia syndrome (POTS) following COVID-19. However, there is a lack of information regarding the incidence and associated factors in Asian population. A retro-prospective study was conducted to evaluate patients with symptoms suggestive of POTS or other autonomic dysfunctions. These symptoms last at least 3 months after PCR-proven COVID-19. Exclusion criteria were age under 18 years old, pregnancy, and pre-COVID-19 autonomic dysfunction symptoms. Patients with a symptom severity score greater than two were assessed with blood tests, 24-h Holter, 24-h ambulatory blood pressure, echocardiogram, and head-up tilt table (HUTT). Seven hundred ninety-three patients were interviewed at 146 ± 37 days after COVID-19. The majority of patients were middle-aged females (53%). Of those, 15 patients had the symptom severity score greater than 2. Out of those 15 patients, 12 had positive HUTT (1 demonstrating POTS, 10 neurocardiogenic syncope, and 1 orthostatic hypotension). Among those with positive HUTT patients, C-reactive protein (CRP) was significantly higher (OR 1.01; p-value 0.041). Fatigue and dyspnea on exertion were the two most complaint symptoms. This study shows the incidence of autonomic dysfunction and POTS is 1.5% (12/793) and 0.1% POTS (1/793), respectively, in a primary care setting (among general post-COVID-19 patients). The most common symptoms for these patients were fatigue and dyspnea.

A Retrospective Chart Review of the Head-Up Tilt Table Test at a Tertiary Care University Hospital

Objectives: Syncope is a non-traumatic and self-limiting transient loss of consciousness (TLOC) caused by momentary cerebral hypo-perfusion. It can be classified into orthostatic, cardiac, and vasovagal etiologies, distinguished using the up-tilt table test (HUTT). Our objective was to determine the characteristics of patients undergoing HUTT for TLOC. Methodology: We conducted a single-center retrospective chart review of patients aged &gt; 16 years who underwent HUTT from January 2010 to March 2020 at the cardiology and neurology departments of Shifa International Hospital, Islamabad, Pakistan. Charts were reviewed for basic demographic data and indications and outcomes of HUTT. Results: Our study included 496 patients with 72.2% males and a mean age of 51.1 ± 19.08 years. Vasovagal syncope was the most common etiology (79.8%, 158), followed by orthostatic syncope (11.6%, 23), autonomic syncope (6.1%, 12) and postural orthostatic tachycardia syndrome (2.5%, 5). Vasovagal syncope was divided into three subtypes, with the most common being mixed type (82.3%, 130), followed by pure vasodepressor (14.6%, 23) and cardio-inhibitory (3.2%, 5). The two most common prodromal symptoms were loss of consciousness (45.8%, 227) with or without preceding dizziness, followed by dizziness alone (34.5%, 171). Both symptoms had a statistical significance when compared to the diagnostic yield of HUTT testing (p&lt;0.05). No significant correlation (p&gt;0.05) was found between presenting symptoms, age, gender, and HUTT outcomes. Conclusion: The most common etiology of syncope is vasovagal, predominantly the mixed type. LOC and dizziness were significantly associated with the HUTT yield.

Brain MRI and EEG overemployment in patients with vasovagal syncope: results from a tertiary syncope unit

BackgroundThe diagnosis of vasovagal syncope (VVS) is mainly based on history-taking and physical examination. However, brain Magnetic Resonance Imaging (MRI) and Electroencephalogram (EEG) are commonly used in the diagnostic course of VVS, despite not being indicated in the guidelines. This study aims to find the possible associated factors with the administration of brain MRI and EEG in patients with VVS.MethodsPatients with a diagnosis of VVS from 2017 to 2022 were included. Several demographic and syncope features were recorded. The association of these was assessed with undergoing MRI, EEG, and either MRI or EEG. Univariate and multivariable logistic regression models were also used to calculate odds ratios (OR) and 95% confidence intervals (CI).ResultsA total of 1882 patients with VVS were analyzed, among which 810 underwent MRI (43.04%), 985 underwent EEG (52.34%), and 1166 underwent MRI or EEG (61.96%). Head trauma (OR 1.38, 95% CI 1.06 to 1.80), previous neurologist visit (OR 6.28, 95% CI 4.24 to 9.64), and gaze disturbance during syncope (OR 1.75, 95% CI 1.13 to 2.78) were all positively associated to the performance of brain MRI/EEG. Similar results were found for urinary incontinence (OR 2.415, 95% CI 1.494 to 4.055), amnesia (OR 1.421, 95% CI 1.053 to 1.930), headache after syncope (OR 1.321, 95% CI 1.046 to 1.672), and tonic-clonic movements in head-up tilt table test (OR 1.501, 95% CI 1.087 to 2.093). However, male sex (OR 0.655, 95% CI 0.535 to 0.800) and chest pain before syncope (OR 0.628, 95% CI 0.459 to 0.860) had significant negative associations with performing brain MRI/EEG.ConclusionBased on our findings, performing MRI or EEG was common among VVS patients while it is not indicated in the majority of cases. This should be taken into consideration to prevent inappropriate MRI/EEG when there is a typical history compatible with VVS.

Postural orthostatic tachycardia syndrome (POTS) and other autonomic dysfunction following COVID-19 infection: incidence, characteristic and associating factors

Abstract Background Long-COVID syndrome has become a new health concern. Many major clinical centers worldwide have experienced more patients with symptoms suggestive of autonomic dysfunction especially Postural Orthostatic Tachycardia syndrome (POTS). These patients were previously diagnosed with COVID19. However, there is lack of incidence and associating factors in Asian population. Objective This study investigated the incidence, associating factors and clinical features in patients with new-onset symptoms suggesting POTS or other autonomic disorders following COVID-19 infection. Methods We conducted a retro-prospective study to evaluate patients from COVID-19 outpatient clinic who have symptoms suggestive of POTs or other autonomic dysfunctions. These symptoms must last at least three months after PCR proven COVID 19 infections. Exclusion criteria were age &amp;lt; 18 years old, pregnancy and pre COVID-19 infection symptoms. Patients with symptoms severity score greater than two were assessed with blood tests, 24-hour Holter, 24-hour ambulatory blood pressure, echocardiogram and underwent head-up tilt table (HUTT). Results 793 patients were interviewed at a mean of 146± 37 days after COVID-19 infection. Majority of patients are middle-aged female. 15 patients with symptoms severity score &amp;gt;2 were investigated. Out of those 15 patients, 12 have positive HUTT (1 demonstrating POTS, 10 neuro cardiogenic syncope, and 1 orthostatic hypotension). Among those positive HUTT patients, C-reactive protein (CRP) is significantly higher (OR 1.01; p-value 0.041). Fatigue and orthostatic intolerance are the two most complaint symptoms. All patients with positive HUTT have non dipping pattern on 24-hour ambulatory BP monitoring. Conclusions This study demonstrates incidence of 1.5% (12 out of 793) autonomic dysfunction and 0.1% POTS (1 out of 793) among post COVID-19 outpatient cases . Associating factor includes high CRP during infection. Most complaint symptoms are fatigue and orthostatic intolerance.Patient flow diagramType and severity of symptoms

Abstract 11832: Carotid Sinus Massage Can Obviate the Need for Tilt Table Testing in Patients With Undiagnosed Vasodepressor Syncope

Introduction: Head-up tilt table (HUTT) testing is typically utilized for patients with syncope where the diagnosis is unclear but suspicion of a vasovagal etiology. Carotid sinus massage (CSM) can be used to elicit a vasopressor response though typically used to diagnose carotid sinus hypersensitivity. The usual protocol of HUTT consists of baseline CSM, 30-mins of HUTT, a repeat of CSM, and drug infusion. This is time-consuming and tedious. Hypothesis: CSM has a high predictive value for a vasodepressor response and may prevent the need for the completion of the HUTT protocol. Methods: Consecutive patients with clinical suspicion of vasovagal syncope underwent HUTT. Protocol consisted of baseline CSM in the supine posture, 30-mins of HUTT at 60 degrees, repeat CSM, and infusion of isoproterenol infusion from 1 to 3 mcg/min. Beat-to-beat blood pressure (BP) monitoring was performed non-invasively and standard cuff BP monitoring every minute. Positive tilt was defined as a drop in BP by more than 20 mmHg with reproducible symptoms (correlation to clinical symptoms). Results: 55 consecutive patients with a history of syncopal episode(s) underwent HUTT. 46 were females and 9 were male with a mean age of 54.4 ± 17.4 years old. They presented symptoms suggestive of a vasovagal etiology but were not diagnostic. 12 out of 55 (21.8%) patients had a positive reproducible response with supine CSM. 11 out of 12 of these patients subsequently had a positive result with protocol completion. This provided a positive predictive value (PPV) of 92%. 36 out of 55 (65.5%) patients had a negative response to CSM. All 36 had a negative result on completion of the HUTT protocol. This provided a negative predictive value (NPV) of 100%. 7 out of 55 (12.7%) patients had a “borderline” positive supine CSM. All 7 had a positive result with the completion of the HUTT protocol. Of note, these patients became positive only with isoproterenol infusion. Conclusions: CSM in the supine posture has a high PPV and NPV in eliciting a possible vasodepressor etiology. A full HUTT protocol may be only required in a patient who presents with a “borderline” CSM response in the supine posture. Therefore, CSM may easily be performed at the bedside with a monitor and a BP apparatus obviating the need for the full HUTT protocol.

Abstract 16323: Functional Autoantibody Analysis in Post-Acute Sequela of COVID-19 Patients With and Without Pots: A Case Control Study

Introduction: Post-Acute Sequela of COVID-19 (PASC) occurs after recovery from the initial illness. Autonomic dysfunction (AD) may explain these findings. We have previously shown orthostatic intolerance (OI) on standard Italian protocol head-up tilt table in 23 of 24 prospectively studied subjects with PASC and no prior OI. Postural orthostatic tachycardia syndrome (POTS) was noted in 4 of the 23. POTS is associated with elevated levels of autoantibodies. There is a paucity of data evaluating autoantibody presence in subjects with PASC related POTS. Hypothesis: We hypothesized that individuals with PASC related POTS would demonstrate higher levels of certain autoantibodies than controls. Methods: We recruited healthy, COVID-19 PCR negative controls, all previously vaccinated for COVID, who were age and gender matched with the 4 previously identified PASC related POTS patients. Serum was tested for autoantibodies in both groups. Results: Mean ages for the PASC related POTS and control groups were 29 and 31 years, respectively. The PASC related POTS patients had higher levels of functional autoantibodies to several G-protein coupled receptors than controls. The median values for adrenergic A1, adrenergic B2, muscarinic M4, angiotensin 2 and endothelin receptors, comparing controls to PASC related POTS patients, were 10.4 vs 27.5, 14.9 vs 38.5, 7.8 vs 29.0, 12.2 vs 29.5 and 12.6 vs 31.7 Units/ml, respectively. The small size of the 2 groups precludes meaningful statistical testing, but the box plots in Figure 1 show consistent differences in the concentration of antibody receptors seen between the 2 groups. Conclusions: Functional autoantibodies to several G-protein coupled receptors were seen in higher amount in subjects with PASC related POTS compared to healthy controls. While this is a small, case-control study, it suggests a potential autoantibody mediated mechanism that may explain some of the AD seen in PASC patients with POTS.

Augmented ocular vestibular-evoked myogenic potentials in postural orthostatic tachycardia syndrome.

To delineate the association between otolith function and changes in mean orthostatic blood pressure (BP) and heart rate (HR) in patients with postural orthostatic tachycardia syndrome (POTS). Forty-nine patients with POTS were prospectively recruited. We analyzed the results of ocular vestibular-evoked myogenic potentials (oVEMPs) and cervical vestibular-evoked myogenic potentials (cVEMPs), as well as head-up tilt table tests using a Finometer. The oVEMP and cVEMP responses were obtained using tapping stimuli and 110dB tone-burst sounds, respectively. We measured maximal changes in 5-s averaged systolic BP (SBP), diastolic BP (DBP), and heart rate (HR) within 15s and during 10min after tilting. We compared the results with those of 20 age- and sex-matched healthy participants. The n1-p1 amplitude of oVEMPs was larger in patients with POTS than in healthy participants (p = 0.001), whereas the n1 latency (p = 0.280) and interaural difference (p = 0.199) did not differ between the two. The n1-p1 amplitude was a positive predictor for POTS (odds ratio 1.07, 95% confidence interval 1.01-1.13, p = 0.025). Body weight (p = 0.007) and n1-p1 amplitude of oVEMP (p = 0.019) were positive predictors for ΔSBP15s in POTS, whereas aging was a negative predictor (p = 0.005). These findings were not observed in healthy participants. Augmented utricular inputs may be associated with a relative predominance of sympathetic over vagal control of BP and HR, especially for an early response during orthostasis in patients with POTS. Overt sympathoexcitation due to exaggerated utricular input and lack of readaptation may be associated with the pathomechanism of POTS.

Pacing or ablation for vasovagal syncope: one size does not fit all.

Practical decision pathway for the management of vasovagal syncope. Please see text for details. White circles demonstrate sites of grouping of autonomic ganglia defined as ganglionated plexi (GP). The superior right atrial GP (RSGP) located on the posterosuperior surface of the right atrium adjacent to the junction of the superior vena cava and the right atrium; the superior left atrial GP (LSGP) is on the posterosuperior surface of the left atrium between the pulmonary veins; the inferior (posterior) right atrial GP (RIGP) located adjacent to the interatrial groove; the inferior left atrial GP (LIGP) is identified on the posterolateral surface of the left atrium; and the Marshall tract GP (MTGP) located adjacent the vein of Marshall. *Response to atropine which accelerates sinus node automaticity and increases the speed of atrioventricular conduction should be evaluated in all cases prior recommending CNA to confirm adequate procedural response. A sinus rate increase of ≥25% or a sinus rate ≥90 bpm in the first 15 min after infusion should be considered as a positive response.7,13 CLS, closed loop stimulation; CNA, cardioneuroablation; HUT, head-up tilt table test; and ILR, implantable loop recorder.

Evaluation of syncope in patients referred to afshar heart clinic, yazd, iran from september 2016 to march 2017

Objectives: Syncope is defined as a sudden and transient loss of consciousness followed by complete spontaneous recovery. This study describes the syncope evaluation in patients referred to the Heart Clinic.&#x0D; Methods: This descriptive cross-sectional study was conducted on 60 syncope patients referred to Afshar Heart Clinic of Yazd, Iran, from September 2016 to March 2017. After performing clinical workups, the etiology of syncope was diagnosed in each patient. Electrocardiography and blood pressure measurements were done for all patients. Additional clinical tests, including echocardiography, Holter Monitoring, Head-Up tilt table test (HUTT), electroencephalography, and Magnetic Resonance Imaging, were performed for some patients based on the cardiologist's opinion. The distribution of patient's clinical records, such as age, sex, diabetes, hypertension, history of ischemic heart disease (IHD), duration of syncope, postdrome, prodromal symptoms, and clinical test results according to causes of syncope in patients, were reported.&#x0D; Results: Sixty patients with a mean age of 50.7 ± 20.4 years were evaluated (55% male). Thirty-five patients (58.3%) had Neurally Mediated Syncope, 18 patients (30%) had arterioventricular (AV) Block induced syncope, and 7 (11.7%) patients had Sick Sinus Syndrome (SSS) induced syncope. Age, hypertension, prodromal symptoms, history of IHD, ECG, Holter monitoring, and HUTT results were associated with the cause of the syncope.&#x0D; Conclusions: Cardiac syncopes (AV-Block induced and SSS induced) were related to older age, hypertension, abnormal electrocardiogram, and abnormal Holter monitoring results. Neurally mediated syncope was associated with younger age, prodromal symptoms, and abnormal HUTT results.

Autonomic dysfunction after mild acute ischemic stroke and six months after: a prospective observational cohort study

IntroductionAutonomic dysfunction is prevalent in ischemic stroke patients and associated with a worse clinical outcome. We aimed to evaluate autonomic dysfunction over time and the tolerability of the head-up tilt table test in an acute stroke setting to optimize patient care.Patients and methodIn a prospective observational cohort study, patients were consecutively recruited from an acute stroke unit. The patients underwent heart rate and blood pressure analysis during the Valsalva maneuver, deep breathing, active standing, and head-up tilt table test if active standing was tolerated. In addition, heart rate variability and catecholamines were measured. All tests were performed within seven days after index ischemic stroke and repeated at six months follow-up.ResultsThe cohort was comprised of 91 acute stroke patients, mean (SD) age 66 (11) years, median (IQR) initial National Institute of Health Stroke Scale 2 (1–4) and modified Ranking Scale 2 (1–3). The head-up tilt table test revealed 7 patients (10%) with orthostatic hypotension. The examination was terminated before it was completed in 15%, but none developed neurological symptoms. In the acute state the prevalence of autonomic dysfunction varied between 10–100% depending on the test. No changes were found in presence and severity of autonomic dysfunction over time.ConclusionIn this cohort study of patients with mild stroke, autonomic dysfunction was highly prevalent and persisted six months after index stroke. Head-up tilt table test may be used in patients who tolerate active standing. Autonomic dysfunction should be recognized and handled in the early phase after stroke.

Effects of short-term hypercaloric nutrition on orthostatic tolerance in healthy individuals: a randomized controlled crossover study

Reduced-caloric intake lowers blood pressure through sympathetic inhibition, and worsens orthostatic tolerance within days. Conversely, hypercaloric nutrition augments sympathetic activity and blood pressure. Because dietary interventions could be applied in patients with syncope, we tested the hypothesis that short-term hypercaloric dieting improves orthostatic tolerance. In a randomized crossover trial, 20 healthy individuals (7 women, 26.7 ± 8 years, 22.6 ± 2 kg/m2) followed a 4-day hypercaloric (25% increase of energy intake by fat) or normocaloric nutritional plan, with a washout period of at least 23 days between interventions. We then performed head-up tilt table testing with incremental lower body negative pressure while recording beat-by-beat blood pressure and heart rate. The primary endpoint was orthostatic tolerance defined as time to presyncope. Time to presyncope during combined head-up tilt and lower body negative pressure did not differ between hypercaloric and normocaloric dieting (median 23.19 versus 23.04 min, ratio of median 1.01, 95% CI of ratio 0.5–1.9). Heart rate, blood pressure, heart rate variability, and blood pressure variability in the supine position and during orthostatic testing did not differ between interventions. We conclude that 4 days of moderate hypercaloric nutrition does not significantly improve orthostatic tolerance in healthy individuals. Nevertheless, given the important interaction between energy balance and cardiovascular autonomic control in the brain, caloric intake deserves more attention as a potential contributor and treatment target for orthostatic intolerance.

Syncopal patients without prodromes exhibit a diverse pattern of adenosine release during head-up tilt test

Abstract Background/Introduction In a significant proportion of patients with neurally-mediated syncope (NMS), the mechanism of syncope remains largely undetermined. Adenosine has been proposed as a central humoral factor in various forms of NMS: high Adenosine Plasma Levels (ADP) are encountered in patients with vasovagal syncope (VVS), low ADP in non-prodromes syncope (NPS), while ADP in patients with situational syncope SS are less well determined. Purpose We sought to assess ADP in patients with different clinical forms of syncope, with an emphasis on the presence or absence of prodromal symptoms, as well as the relation between ADP and the outcomes of Head-Up Tilt Table Test (HUTT) and Adenosine test (ADT). Methods Patients with different clinical types of NMS (n=124), i.e., VVS, NPS, or SS, were investigated using a standard protocol including HUTT and ADT. During HUTT, ADP was measured in the supine position, at table tilting, and in syncope. Results Baseline ADP did not differ among groups. ADP at syncope were higher in NPS compared to VVS (1.55±1.29 vs 0.16±0.05 μM, p=0.03) and SS (0.15±0.05 μM, p=0.02). In NPS, ADP increased from the supine position to the time of syncope (0.47±0.25 to 1.55±1.29 μM, p=0.04). In VVS, ADP increased only from the supine to the tilt position (0.23±0.04 to 0.35±0.10 μMu, p=0.02), while in SS ADP did not change in any stage of HUTT. SS was associated with cardioinhibitory HUTT (OR 3.40, 95% CI 1.05 to 9.56, p=0.04) and positive ADT (OR 4.22, 95% CI 1.47 to 11.46, p=0.012). Conclusion(s) A distinct pattern of ADP increase is noted during HUTT in NPS, suggesting that an excessive increase of ADP may play the key role in triggering this type of clinical presentation of syncope independently of the baseline ADP. Cardioinhibition prevails in patients with SS without clear adenosine involvement. Such observations contribute to an enhanced understanding of the pathophysiology of different clinical forms of syncope which may offer the possibility to tailor the management approach appropriately. Funding Acknowledgement Type of funding sources: None.