Negative Tilt Test Research Articles

Efficacy of catheter ablation in ganglionated plexus for malignant vasovagal syncope children.

Malignant vasovagal syncope in children seriously affects their physical and mental health. Our study aimed to explore the efficacy of catheter ablation in ganglionated plexus with malignant vasovagal syncope children. Catheter ablation of ganglionated plexus was safe and effective in children with malignant vasovagal syncope and can be used as a treatment option for these children. A total of 20 children diagnosed with malignant vasovagal syncope were enrolled in Beijing Children's Hospital, affiliated with Capital Medical University. All underwent catheter ablation treatment of ganglionated plexus. Ganglionated plexuses of the left atrium were identified by high-frequency stimulation and/or anatomic landmarks being targeted by radiofrequency catheter ablation. The efficacy of the treatment was evaluated by comparing the remission rate of post-operative syncopal symptoms and the rate of negative head-up tilt results. Safety and adverse events were evaluated. After follow-up for 2.5 (0.6-5) years, the syncope symptom scores were decreased significantly compared with before treatment [3 (2-4) versus 5 (3-8) scores, P < 0.01]. Eighty-five per cent (17/20) children no longer experienced syncope, whilst 80% (16/20) children showed negative head-up tilt test after treatment. No adverse effects such as cardiac arrhythmia occurred in the children.

Asystole on loop recorder in patients with unexplained syncope and negative tilt testing: age distribution and clinical predictors

BackgroundApproximately 50% of patients with unexplained syncope and negative head-up tilt test (HUTT) who have an electrocardiogram (ECG) documentation of spontaneous syncope during implantable loop recorder (ILR) show an asystolic pause at the time of the event.ObjectiveThe aim of the study was to evaluate the age distribution and clinical predictors of asystolic syncope detected by ILR in patients with unexplained syncope and negative HUTT.MethodsThis research employed a retrospective, single-center study of consecutive patients. The ILR-documented spontaneous syncope was classified according to the International Study on Syncope of Uncertain Etiology (ISSUE) classification.ResultsAmong 113 patients (54.0 ± 19.6 years; 46% male), 49 had an ECG-documented recurrence of syncope during the observation period and 28 of these later (24.8%, corresponding to 57.1% of the patients with a diagnostic event) had a diagnosis of asystolic syncope at ILR: type 1A was present in 24 (85.7%), type 1B in 1 (3.6%), and type 1C in 3 (10.7%) patients. The age distribution of asystolic syncope was bimodal, with a peak at age < 19 years and a second peak at the age of 60–79 years. At Cox multivariable analysis, syncope without prodromes (OR 3.7; p = 0.0008) and use of beta blockers (OR 3.2; p = 0.002) were independently associated to ILR-detected asystole.ConclusionsIn patients with unexplained syncope and negative HUTT, the age distribution of asystolic syncope detected by ILR is bimodal, suggesting a different mechanism responsible for asystole in both younger and older patients. The absence of prodromes and the use of beta blockers are independent predictors of ILR-detected asystole.

Abstract 12760: Microvascular Endothelial Dysfunction in Postural Orthostatic Tachycardia Syndrome Associated With Post-Acute Sequelae of COVID-19

Introduction: Post-acute sequelae of COVID-19 (PASC) is a novel clinical syndrome. We have previously reported that PASC patients can develop postural orthostatic tachycardia syndrome (POTS) and that COVID-19 induce microvascular endothelial dysfunction in acutely ill, hospitalized patients, that persist up to four months post discharge. Whether microvascular endothelial dysfunction contributes to POTS pathophysiology in PASC remains unclear. Hypothesis: Patients with PACS combined with POTS have impaired microvascular endothelial function. Methods: PASC patients (n=44) with mild SARS-CoV-2 infection (not hospitalized) were recruited from the post-COVID multidisciplinary clinic at Karolinska University Hospital. PASC diagnosis was based on the WHO PASC criteria. POTS was diagnosed in 21 patients (PASC + POTS) while 23 had a negative head-up tilt test (PASC - POTS). Age- and gender-matched healthy subjects (n=15) served as controls. Microvascular endothelial function was quantified as reactive hyperemia index (RHI) determined from the changes in pulse amplitude tonometry before and after a 5 min episode of arterial occlusion. Stress-perfusion cardiac magnetic resonance imaging (cMRI) with adenosine was performed in a subset of patients. Results: Mean age was 42±11 years and 95 % were women among PACS patients. Time from COVID-19 symptom onset to study inclusion was 18±3 months. RHI was significantly lower in PASC + POTS than in healthy controls and PASC - POTS (Figure 1). The prevalence of cardiac microvascular dysfunction on cMRI did not differ between the PASC groups (8% in PASC + POTS vs. 13% in PASC - POTS, p=1.00). All subjects with microvascular dysfunction on cMRI except one had a RHI below the cutoff (1.67) indicating microvascular dysfunction. Conclusions: Microvascular endothelial dysfunction is common in patients with PACS-associated POTS and may cause stress-induced myocardial ischemia up to 18 months after a mild primary infection.

Abstract 12737: Baseline Carotid Sinus Massage in the Supine Position Predicts Outcome of Head Up Tilt Table Testing: Potential for Abbreviating the Tilt Table Test Protocol

Introduction: Carotid sinus massage (CSM) has been used to evaluate carotid sinus hypersensitivity. Its role in evaluating a vasodepressor response has not been well studied. CSM can also result in a vasodepressor response in the absence of significant bradycardia. Its role in predicting the subsequent outcome of head-up tilt testing (HUT) is not well defined. Hypothesis: A vasodepressor response elicited with baseline carotid sinus massage (CSM) may predict the subsequent outcome of HUT. Methods: In this prospective study Consecutive patients with a history suggestive of a reflex neurocardiogenic etiology underwent HUT. Patients underwent HUT testing using a standard protocol, including baseline CSM in the supine posture followed by HUT testing at 60 degrees for 30 minutes. If negative, a repeat of CSM was performed in the upright posture. Then, isoproterenol was infused in incremental dose 1 to 3 mcg/minute. Results: 25 patients (20 females and 5 males) with a mean age of 52.87±6.77 years underwent HUT. 5 out of 25 (20%) patients had a positive tilt result for a vasodepressor response. 4 of these 5 patients had a significant vasodepressor response (symptomatic hypotension BP drop less than 30 mmHg) without significant bradycardia (HR less than 50 BPM) during CSM in the supine posture. Of these patients, 3 patients became positive during HUT and 1 patient became positive during isoproterenol infusion. The positive predictive value was 0.8. Sensitivity was 67%. 20 out of 25 (80%) patients had a negative tilt result for a vasodepressor response despite protocol completion. 18 of these 20 patients had no drop in BP during CSM and no significant bradycardia. The negative predictive value was 0.9. The specificity was 94.74%. 2 of these patients had a negative response on CSM but a borderline response at HUT with borderline symptoms with the isoproterenol. These 2 had a transient drop in BP when CSM was repeated at the end of 30 minutes during the head-up position. Conclusions: In this population of patients, a negative CSM in the supine posture predicted a subsequent negative Tilt test. Baseline CSM can be performed at the bedside and may obviate the need for full tilt table testing even for patients with a clinical diagnosis of reflex syncope (vasodepressor).

The Influence of Age on Cerebral Tissue Oxygenation in Vasovagal Syncope and Orthostatic Hypotension.

Age-related physiological impairment increases susceptibility to syncope. We tested the hypotheses that cerebral oxygenation during orthostatic provocation, as well as the level at which syncope occurs, differs according to age. Non-invasive hemodynamic monitoring and cerebral oximetry were applied during a head-up tilt test in 139 patients with vasovagal syncope (mean (SD) 45, (17) years, 60%-female); 121 patients with orthostatic hypotension (61.4 (19.2) years, 49.6%-female); and 82 patients with a negative head-up tilt test (45 (18) years, 61%-female). Group differences in cerebral tissue oxygenation levels and systolic blood pressure were assessed in supine at 3 and 10 min of orthostatic provocation, 30 s before (i.e., presyncopal phase) and during syncope in age groups of <30, 30–60, and >60 years. During the head-up tilt test, cerebral tissue oxygenation at the presyncopal phase decreased with age, both in patients with vasovagal syncope (<30 years: 66.9 ± 6.2, 30–60: 64.5 ± 6.1, >60: 62.2 ± 5.8%; p = 0.009) and orthostatic hypotension (<30: 67.4 ± 4.4, 30–60: 61.6 ± 6.2, >60: 57.5 ± 3.9; p < 0.001). Mean systolic blood pressure at the presyncopal phase did not differ according to age. Cerebral oxygenation prior to syncope in older individuals with vasovagal syncope and orthostatic hypotension is lower compared with younger individuals independently of systolic blood pressure. This suggests that the level of cerebral oxygenation at which syncope is elected is lower in older individuals.

Paleomagnetic Constraints From South Georgia on the Tectonic Reconstruction of the Early Cretaceous Rocas Verdes Marginal Basin System of Southernmost South America

AbstractSouth Georgia exists as a microcontinent along the North Scotia Ridge ∼1,700 km east of Cape Horn. The tectonostratigraphic units of South Georgia have long been correlated with those of the Fuegian Andes of southernmost South America. Accordingly, South Georgia has been regarded as a continuation of the Late Jurassic–Early Cretaceous Rocas Verdes marginal basin system, formerly situated south of Burdwood Bank and east of Cape Horn. To test this, paleomagnetic analysis of samples from the Larsen Harbour Complex, Drygalski Fjord Complex, and Annenkov Island Formation of South Georgia showed that 21 sites yield a mean direction of D = 328.5°, I = −62.1° (a95 = 3.5°) and a paleomagnetic pole at 068.2°E, 67.2°N, A95 = 4.7°. The consistency of directions and strong polarity bias, plus indications of a negative differential tilt test, point to a secondary magnetization acquired in the Late Cretaceous. Comparison of predicted versus observed directions for South Georgia relative to stable South America indicate 27.2 ± 11.2° of counter‐clockwise rotation (and 10.5° ± 4.5° of northward tilting) since the acquisition of magnetization. These results are consistent with paleomagnetic studies from the Fuegian Andes and support a paleoposition of the South Georgia microcontinent south of Burdwood Bank as strongly indicated by the geologic evidence. Partitioning this rotation between oroclinal bending during the Rocas Verdes basin collapse in the Late Cretaceous and left‐lateral translation along the North Scotia Ridge is not possible on paleomagnetic grounds, but the co‐linearity of Andean structures between the restored microcontinent and Tierra del Fuego indicates the former.

Genetic markers of vasovagal syncope.

Vasovagal syncope may have a genetic predisposition. It has a high prevalence in some families, and children of a fainting parent are more likely to faint than those without a parent who faints. Having two fainting parents or a fainting twin increases the likelihood even further. Several genotypes appear to associate with the phenotype of positive tilt tests, but the control subjects are usually those who faint and have negative tilt tests. Twin studies, highly focused genome-wide association studies, and copy number variation studies all suggest there are loci in the genome that associate with vasovagal syncope, although the specific genes, pathways, and proteins are unknown. A recent multigenerational kindred candidate gene study identified 3 genes that associate with vasovagal syncope. The best evidence to date is for central signaling genes involving serotonin and dopamine. Genome-wide association studies to date have not yet been helpful. Our understanding of the genetic correlates of vasovagal syncope leaves ample opportunity for future work.

Assessment of Left Ventricular Outflow Tract Velocity Time Integral in Pediatric Patients with Vasovagal Syncope

Background Syncope is an important and common clinical condition, and the neurally mediated syncope is the most frequent type of syncope. Head up tilt testing is considered as a first line diagnostic test. The aim of this study was to assess the left ventricular outflow tract velocity time integral in echocardiography of pediatric patients with vasovagal syncope. Materials and Methods: In this case-control study, between January 2019 and December 2020 92 patients who referred in in Mofid Children Hospital in Tehran, Iran, for vasovagal syncope in the case group and 92 healthy children with maximum matching of sex and age in the control group were included in the study. Demographic, clinical and para-clinical data were recorded for each patient in the respective checklists, and HUTT and echocardiography were reviewed, then the results of two groups were compared. Results: The mean age of the patients with vasovagal syncope was 12.12 ±5.18 years. 66.3% of patients in the case group were female. There was a statistically significant relationship between LVOT-VTI and positive result of HUTT (p <0.001). There was no relationship between LVOT VTI in case and control groups (p=0.14). Conclusion The mean LVOT VTI index in patients with negative tilt test is higher than patients with positive tilt test. Although echocardiographic indices in children with vasovagal syncope are in normal range, accurate measurement of LVOT-VTI can be helpful in predicting a positive HUTT result.

Pacing in vasovagal syncope: Physiology, pacemaker sensors, and recent clinical trials—Precise patient selection and measurable benefit

The role of pacing in vasovagal syncope (VVS) is considered from a physiological basis. Most VVS patients lose consciousness due to hypotension before severe bradycardia/asystole occurs. Patients who benefit from dual-chamber pacing typically are older with highly symptomatic, late-onset, frequent and severe syncope with short/no prodrome and documented severe cardioinhibition. Tilt testing is of value in patients with recurrent unexplained syncope to identify important hypotensive susceptibility stemming from reduced venous return and stroke volume (SV). A negative tilt test in vasovagal patients with spontaneous asystole documented by an implantable/insertable loop recorder is associated with lower syncope recurrence rates after pacemaker implantation. Pacing may be more effective if triggered by sensor detection of a parameter changing earlier in the reflex than bradycardia when SV may still be relatively preserved. In this regard, detection of right ventricular impedance offers promise. Conservatism is recommended, limiting pacing in VVS to a small subset of symptomatic older patients with clearly documented cardioinhibition and paying particular attention to the timing of loss of consciousness in relation to asystole/bradycardia. Understanding VVS physiology permits application of well-timed, appropriate pacing that yields benefit for highly symptomatic patients.

The Search for the Genes of Vasovagal Syncope.

Only humans faint, and not all do so. Syncope tends to recur, and the predisposition to syncope can persist over many decades. Observations such as these have suggested that there may be a genetic predisposition to vasovagal syncope. It seems to have a high prevalence in some families; having a parent who faints increases the likelihood of an offspring fainting, and this is increased even further if both biological parents faint. Numerous studies have correlated a number of genotypes with positive tilt tests. However, the control subjects are usually those who faint, but have negative tilt tests, making the conclusions about association with the clinical phenotype less certain. Twin studies, highly focused genome-wide association studies, and gene duplicate studies all suggest there are sites in the genome that associate with vasovagal syncope, although the specific genes, pathways, and proteins are unknown. A recent large, candidate gene study of kindreds with high, multigenerational prevalence of the vasovagal syncope identified 3 genes that associate with vasovagal syncope. Our understanding of the genetic correlates of vasovagal syncope is in its infancy, with much to be understood.

The benefit of pacemaker therapy in patients with neurally mediated syncope and documented asystole: a meta-analysis of implantable loop recorder studies

Although the efficacy of cardiac pacing in patients with neurally mediated syncope (NMS) and documented asystole is established, a more robust point estimate of the benefit, which is not possible with any individual study, is lacking. We undertook a meta-analysis of individual participant data from four studies that reported follow-up data on syncope recurrence with cardiac pacing in patients with NMS who had had an electrocardiographic (ECG) documentation of an asystolic event by means of implantable loop recorder (ILR). Of a total of 1046 patients, who had ILR implanted, 383 (36.6%) patients had an ECG documentation of a diagnostic event during mean follow-up of 13 ± 10 months. Of these, 201 (52%) patients, corresponding to 19.2% of the total ILRs, had an asystolic event of 12.8 ± 11.0 s duration documented and met the criteria for pacemaker therapy. Follow-up was available in 121 (60%) of those patients with asystolic events. Syncope recurred after pacing in 18 (14.9%) patients with an actuarial rate of 13% [95% confidence interval (CI) ±6] at 1 year, 21% (95%CI ±10) at 2 years, and 24% (95%CI ±11) at 3 years. On multivariable Cox regression analysis, positive tilt test response was the only significant predictor of syncope recurrence with a hazard ratio (95% CI) of 4.3 (1.4-13). On the contrary, type of asystolic event (sinus arrest or atrioventricular block), prodrome, cardiac abnormalities, number and duration of history of syncope, age, and gender were not predictors of recurrence of syncope. A long asystolic pause, suitable for pacemaker therapy, was found in one of five patients with ILR. After pacemaker implantation, most of these patients remained free of syncope recurrence for up to 3 years. The benefit of pacemaker was greater in patients with negative tilt test.

Should we treat severe vasovagal syncope with a pacemaker?

Cardiac pacing for vasovagal syncope (VVS) addresses the cardioinhibitory component of the reflex but cannot directly affect vasodepression, which occurs in every reflex even when hidden by dominant cardioinhibition. The randomized controlled trials of pacing in VVS have, after almost 2 decades, determined that a small number of patients can benefit because their vasodepressor component is not severe. Early studies compared pacing with no therapy yielding highly significant benefits. Subsequently, all study patients had implanted devices with half being switched off. No benefit was seen. The ISSUE-3 study found significant benefit (P < 0.039) in prevention of syncope recurrence in older patients. A sub-study later showed those with negative tilt tests, otherwise indistinguishable from tilt-positives, had 5% recurrence in 21 months (P < 0.004). There is acceptance that pacing must be dual chamber, but the question of how pacing is delivered remains open. Relying on falling heart rate is insufficient, probably because it occurs too late. Other algorithms which indirectly detect neuroendocrine changes earlier than heart rate fall may have useful application. In clinical terms, the patient to be considered for pacing should not be young and have severe symptoms. Ideally, tilt testing should be negative implying vasodepression of lesser severity and, therefore, yielding fewer syncope recurrences. When selecting pacing, additional concern must be given to regression to the mean of symptoms, severe to less severe. Patients seek help when they are at their worst. Moreover, many years of pacing are unlikely to be free of complications related to implanted hardware.

Copeptin levels in patients with vasovagal syncope

Background and purposeVasovagal syncope (VVS) is linked to more than one pathophysiologic mechanisms. Copeptin, an emerging cardiovascular marker, is a surrogate for arginine-vasopressin, which increases following VVS. We aimed to assess the dynamic pattern of copeptin levels in typical VVS, categorized by the degree of vasoconstriction during orthostasis, and healthy controls. MethodsThe following groups were studied: Group A (n=21), with adequate limb vasoconstriction during the first min. of tilt, assessed by limb plethysmography (at least 30% flow reduction); Group B (n=15), showing impaired vasoconstriction during orthostasis (<10% reduction); Group C (n=18), history of VVS and negative tilt test result; Group D (n=18), healthy controls. Copeptin plasma levels were assessed before and 5min following tilt test positivity or termination. ResultsBaseline copeptin values were similar in all groups (8.3±6.4 in Group A, 5.7±2.3pmol/l in B, 6.0±1.9 in C, and 6.9±2.6 in D, p: 0.41). Significant increases in copeptin during tilt were observed in all Groups of VVS patients (A, B, C), including those with negative tilt (Group C: from 6.0±1.9 to 27.7±12.6pmol/l, p: 0.001), but not in controls. Following tilt termination, a greater increase was observed in copeptin values in Group B vs all other Groups A, C, and D (111.6±63.5 vs 29.5±51.3, 27.7±12.6, and 8.3±2.9, respectively). ConclusionsCopeptin increases following tilt not only in VVS with a positive response, but also in typical history patients with a negative test. Increased copeptin levels following orthostasis may be useful for diagnosing VVS.

Standardized algorithm for cardiac pacing in older patients affected by severe unpredictable reflex syncope: 3-year insights from the Syncope Unit Project 2 (SUP 2) study.

The aim of this study was to determine the long-term effects and determinants of success of cardiac pacing in patients affected by reflex syncope enrolled in the Syncope Unit Project 2 (SUP 2) study. Initial results have validated the effectiveness of a standardized guideline-based algorithm which can be used in clinical practice in order to select suitable candidates for cardiac pacing. In this prospective, multicentre, observational study, patients aged >40 years, affected by severe unpredictable recurrent reflex syncope, underwent carotid sinus massage (CSM), followed by tilt testing (TT) if CSM was negative, followed by implantation of an implantable loop recorder (ILR) if TT was negative. Those who had an asystolic response to one of these tests received a dual-chamber pacemaker. Of 281 patients who met the inclusion criteria, 137 (49%) received a pacemaker and were followed up for a mean of 26 ± 11 months: syncope recurred in 25 (18%) of them. At 3 years, the actuarial syncope recurrence rate was 20% [95% confidence interval (CI) 12-30] and was significantly lower than in 142 patients who did not receive a pacemaker and were observed by means of an ILR [43% (95% CI 29-57), P = 0.01]. The 3-year recurrence rate was not different among 78 CSM+, 38 TT+, and 21 ILR+ patients, whereas it was lower in 20 patients with negative TT [5% (95% CI 0-15)] than in 61 patients with positive TT [24% (95% CI 10-38)]. The benefit of cardiac pacing is maintained at 3 years, irrespective of the index diagnostic test, and is maximum in patients with negative TT. URL: http://www.clinicaltrials.gov. Unique identifier: NCT01509534.

Cardiac Autonomic Response to Active Standing in Adults With Vasovagal Syncope.

Little is known about the autonomic response to active standing in vasovagal syncope, and most works have focused on children or adolescents. The aim of this work was to study the changes in cardiac autonomic modulation in adult patients with vasovagal syncope through heart rate variability analysis with linear and short-term complexity (alpha-1) indexes during supine position and active standing, in patients with positive or negative head-up tilt test (HUTT). Twenty-five patients with vasovagal syncope were included. Heart rate variability linear and short-term complexity (alpha-1) indexes were recorded during an active standing test (15 minutes in each position) and compared among patients grouped by HUTT outcome and between positions. During supine position, positive HUTT (+HUTT) patients had longer mean RR (1016 [850-1051] milliseconds), higher pNN50 (17.7 [9.2-26.2]), lower sympathovagal balance (1.3 [0.5-1.7]), and alpha-1 (0.9 [0.8-1.0]) than negative HUTT (-HUTT) patients (871 [776-969] milliseconds, 8.8 [2.1-14.5], 2.9 [1.3-3.9], and 1.2 [1.0-1.1], respectively). During active standing, heart rate and alpha-1 increased in both groups; in +HUTT patients, pNN50 decreased, whereas sympathovagal balance increased. The magnitude of change between positions of sympathovagal balance and alpha-1 was 6.1 and 4.8 times larger in +HUTT than -HUTT patients, respectively. The underlying cardiac autonomic mechanism in vasovagal syncope may involve different autonomic patterns in subjects with a history of recurrent syncope and +HUTT or -HUTT.

A novel strategy for evaluating tilt test in athletes with syncope.

The tilt test is used for the diagnosis of reflex syncope (RS) and is characterized by low sensitivity, especially in athletes. The objective of the study was the implementation of a novel diagnostic strategy for the tilt test without pharmacologic provocation in athletes based on haemodynamic criteria. A passive tilt test for 30 min was performed in 132 athletes (53 with a history of RS, 79 without RS). Measurement of haemodynamic, heart rate variability (HRV) and baroreflex sensitivity parameters was performed. Tilt testing yielded 34% sensitivity and 94% specificity. Among negative tilt test responders, the ones with RS had increased heart rate (HR) (89 ± 11 vs 81 ± 10 bpm, p < 0.001), stroke index (SI) (40.2 ± 7.1 vs 35.5 ± 9.7 ml/m(2), p = 0.013), cardiac index (CI) (3.5 ± 0.6 vs 2.8 ± 0.8 l/(min·m(2)), p < 0.001) and decreased total peripheral resistance index (TPRI) (2230 ± 362 vs 2965 ± 725 dyne·s m(2)/cm(5), p < 0.001), low frequency component of HRV (76.2% (49.0-88.4) vs 79.7% (10.2-91.1), p = 0.045) during head-up tilt, compared with those without RS. Receiver-operating characteristic (ROC) curve analysis showed that among athletes with a negative tilt test the area under the curve (AUC) values were 0.727 (0.626-0.828) for HR (p < 0.001), 0.707 (0.611-0.804) for SI (p = 0.001), 0.847 (0.774-0.920) for CI (p < 0.001), 0.830 (0.754-0.905) for TPRI (p < 0.001). Further stratification of negative tilt test responders, characterizing their results as positive when TPRI <2800 dyne·s m(2)/cm(5) and CI >3 l/(min·m(2)), resulted in 85% sensitivity and 76% specificity. Our results provide supportive evidence that a novel stratification based on haemodynamic criteria can improve the sensitivity of the tilt test for the diagnosis of RS in athletes.

Ambulatory postural blood pressure changes and history allow a better selection of patients that should undergo a head-up tilt test

Syncope is a common symptom and in most cases it is of a neurally mediated origin. Such patients have to be studied with a careful history and a physical exploration that should include simple maneuvers such as blood pressure (BP) recordings in decubitus and standing position. These tools can suggest diagnosis in a good percentage of patients without the need for expensive or invasive testing. We carried out a prospective observational study measuring BP and heart rate (HR) with the patients in decubitus and just as they stood up. The patients were sent for a tilt table test in different specialized centers. The BP changes were compared to the results of the tilt test. We included 215 patients, 36.1 ± 18.8 years old, 118 (54.9%) feminine, of which 143 (66.5%) had a positive tilt test. Patients with a positive test showed a rise in systolic BP (SBP) (121.7 ± 19.1 vs. 124.2 ± 20, p < 0.005) and in diastolic BP (DBP) (75 ± 11 vs. 78 ± 11.3, p < 0.005) when compared to people with a negative one. On the other hand, percentage BP changes were significantly different (SBP 2.24% vs. 0.48%, p = 0.02; DBP 4.1% vs. 1.2%, p = 0.009). Patients with a positive test had also a lower HR on standing up (72.1 ± ± 11.1 vs. 78.3 ± 17.2, p = 0.01). Patients with neurally mediated syncope showed an elevation of SBP and DBP when standing up actively, unlike subjects with a negative tilt test.

Usability of the head upright tilt test for differentiating between syncopal and seizure-like events in children.

The common diagnosis of loss of consciousness and clonic movements in children is seizure or epilepsy, but in a number of patients these symptoms could also be due to syncope. Over interpreted electroencephalography is misleading in a number of patients; therefore, in addition to a detailed and thorough history, a reliable test is needed to differentiate between these conditions. The aim of the study was to evaluate the utility of the head upright tilt test to differentiate between seizure-like events and syncope in children. A chart review descriptive study was conducted in a tertiary medical center in Ahvaz, Iran. We selected sixteen children (nine boys and seven girls) with convulsions of any type who were first diagnosed as epileptic based on the event description by their parents or caregivers to undergo the head upright tilt test. The main findings were the reproduction of previously presyncopal or syncopal symptoms in the tilted position. Fourteen children showed positive results after conducting the head upright tilt test, and their heart rates were significantly decreased compared to baseline at the onset of the syncopal or presyncopal manifestations. Systolic and diastolic blood pressures were significantly reduced in patients with positive results. In three children who initially had negative head upright tilt tests, intravenous isoproterenol was administered, and all three showed presyncopal and syncopal symptoms. The results indicate that the head upright tilt test could differentiate presyncopal and syncopal events in children who present with seizure-like movements but their history has clues for conclusive syncope.

Reflex syncope and syncope secondary to orthostatic hypotension

Reflex syncope predominantly occurs in younger patients and is the most common type of syncope. Typical contributors to reflex syncope are orthostatic stress, followed by a delayed and inadequate circulatory response consisting of bradycardia (cardioinhibitory type) and hypotension (vasodepressor type). Comparably, syncope may occur after direct activation of the vagus nerve, after emotional distress or pain, and in specific situations, such as coughing and post-micturition. The latter situations are mediated by indirect vagus nerve activation by usually unknown mediators. Syncope mediated by orthostatic hypotension occurs in elderly patients and is mediated by insufficient sympathoadrenergic vasoconstriction, occurring shortly after the onset of the orthostatic situation. A thorough examination of the patient history is the mainstay of diagnostics. Specific testing is only required in uncertain and recurrent cases. In addition to standard diagnostics, tilt table testing can be helpful. A negative tilt test is, however, not definitive. Implanted loop recorders are helpful to diagnose the cardioinhibitory component of reflex syncope and are more sensitive than tilt testing. Treatment of both types of syncope consists of avoiding known situations leading to syncope, early reaction to prodromal syndromes, and physical counterpressure manoeuvers. Drug treatment (e.g. alpha-adrenergic agonists and fludrocortisone) are effective only in patients with orthostatic syncope. In selected patients with reflex syncope of a predominantly cardioinhibitory type, pacemaker implantation may be considered in selected patients.

Superior oblique tucking for treatment of superior oblique palsy.

To investigate the efficacy and safety of isolated superior oblique tucking in the treatment of congenital superior oblique palsy. Twenty-one patients with unilateral congenital superior oblique palsy and lax superior oblique tendon underwent isolated superior oblique tucking and retrospective analysis of the amount of tucking procedure, preoperative and postoperative vertical deviation in the primary position and reading position, abnormal head posture, ocular motility, and corrected objective torsion. Patients were evaluated before and 6 to 12 months after surgery. The average vertical deviation in the primary position was 10.9 ± 3.3 prism diopters (PD) before surgery and 1.5 ± 2.6 PD after surgery (n = 21, P < .05). The average vertical deviation in the reading position was 15.6 ± 3.6 PD before surgery and 2.6 ± 3.1 PD after surgery (P < .05). The average corrected vertical deviation was 9.9 ± 3.2 PD in the primary position and 13.0 ± 3.4 PD in the reading position (P < .05). The amount of tucking ranged from 5 to 12 mm (mean: 8.3 ± 2.3 mm), which was not related to the corrected vertical deviation in the primary and reading positions, the preoperative vertical deviation in the reading position, or the corrected objective torsion. After surgery, all patients had head posture that was normal or less than 5°. Unremarkable superior oblique underaction and negative head tilt test were found in all patients after surgery. All patients had mild Brown syndrome after surgery, but none were symptomatic. Isolated superior oblique tucking is an efficient and safe procedure for treatment of superior oblique palsy with hyperdeviation less than 15 PD in the primary position and remarkable superior oblique underaction. The superior oblique forced duction test was the most important criterion for planning surgery.