Risk factors for syncope recurrence after a positive tilt-table test in patients with syncope

Counter pressure maneuvers for syncope prevention: A semi-systematic review and meta-analysis

Physical counter pressure maneuvers (CPM) are movements that are recommended to delay or prevent syncope (fainting) by recruiting the skeletal muscle pump to augment cardiovascular control. However, these recommendations are largely based on theoretical benefit, with limited data evaluating the efficacy of CPM to prevent syncope in the real-world setting. We conducted a semi-systematic literature review and meta-analysis to assess CPM efficacy, identify literature gaps, and highlight future research needs. Articles were identified through a literature search (PubMed, April 2022) of peer-reviewed publications evaluating the use of counter pressure or other lower body maneuvers to prevent syncope. Two team members independently screened records for inclusion and extracted data. From 476 unique records identified by the search, 45 met inclusion criteria. Articles considered various syncopal conditions (vasovagal = 12, orthostatic hypotension = 8, postural orthostatic tachycardia syndrome = 1, familial dysautonomia = 2, spinal cord injury = 1, blood donation = 10, healthy controls = 11). Maneuvers assessed included hand gripping, leg fidgeting, stepping, tiptoeing, marching, calf raises, postural sway, tensing (upper, lower, whole body), leg crossing, squatting, “crash” position, and bending foreword. CPM were assessed in laboratory-based studies (N = 28), the community setting (N = 4), both laboratory and community settings (N = 3), and during blood donation (N = 10). CPM improved standing systolic blood pressure (+ 14.8 ± 0.6 mmHg, p < 0.001) and heart rate (+ 1.4 ± 0.5 bpm, p = 0.006), however, responses of total peripheral resistance, stroke volume, or cerebral blood flow were not widely documented. Most patients experienced symptom improvement following CPM use (laboratory: 60 ± 4%, community: 72 ± 9%). The most prominent barrier to employing CPM in daily living was the inability to recognize an impending faint. Patterns of postural sway may also recruit the skeletal muscle pump to enhance cardiovascular control, and its potential as a discrete, proactive CPM needs further evaluation. Physical CPM were successful in improving syncopal symptoms and producing cardiovascular responses that may bolster against syncope; however, practical limitations may restrict applicability for use in daily living.

Long-term recurrences and mortality in patients with noncardiac syncope

INTRODUCTION AND OBJECTIVES

There are no in-depth studies of the long-term outcome of patients with syncope after exclusion of cardiac etiology. We therefore analyzed the long-term outcome of this population.

METHODS

For 147 months, we included all patients with syncope referred to our syncope unit after exclusion of a cardiac cause.

RESULTS

We included 589 consecutive patients. There were 313 (53.1%) women, and the median age was 52 [34-66] years. Of these, 405 (68.8%) were diagnosed with vasovagal syncope (VVS), 65 (11%) with orthostatic hypotension syncope (OHS), and 119 (20.2%) with syncope of unknown etiology (SUE). During a median follow-up of 52 [28-89] months, 220 (37.4%) had recurrences (21.7% ≥ 2 recurrences), and 39 died (6.6%). Syncope recurred in 41% of patients with VVS, 35.4% with OHS, and 25.2% with SUE (P=.006). In the Cox multivariate analysis, recurrence was correlated with age (P=.002), female sex (P <.0001), and the number of previous episodes (< 5 vs ≥ 5; P <.0001). Death occurred in 15 (3.5%) patients with VVS, 11 (16.9%) with OHS, and 13 (10.9%) with SUE (P=.001). In the multivariate analysis, death was associated with age (P=.0001), diabetes (P=.007), and diagnosis of OHS (P=.026) and SUE (P=.020).

CONCLUSIONS

In patients with noncardiac syncope, the recurrence rate after 52 months of follow-up was 37.4% and mortality was 6.6% per year. Recurrence was higher in patients with a neuromedial profile and mortality was higher in patients with a nonneuromedial profile.

Management of vasovagal syncope

Vasovagal syncope (VVS) is a very common form of fainting. Treatment begins with patient education about the mechanism of fainting, and the non-lethal nature of vasovagal syncope. In this article, we review several non-pharmacological approaches that form the foundation of our current treatments. These include increases in dietary salt and water intake, the use of compression garments, physical counter-maneuvers and tilt-training. When these approaches are inadequate, medications can sometimes be effective. While the evidence base for the pharmacological treatment of VVS is modest, recent trial data have found drugs to be useful in placebo-controlled randomized trials. For select patients, and those patients more refractory to medications, procedural treatments may be an option. In this review, we discuss the current state of evidence for the non-pharmacological and pharmacological treatments for VVS, as well as some novel, emerging therapies for VVS.

Age-related tilt test responses in patients with suspected reflex syncope

AIMS

Tilt testing (TT) is recognized to be a valuable contribution to the diagnosis and the pathophysiology of vasovagal syncope (VVS). This study aimed to assess the influence of age on TT responses by examination of a large patient cohort.

METHODS AND RESULTS

Retrospective data from three experienced European Syncope Units were merged to include 5236 patients investigated for suspected VVS by the Italian TT protocol. Tilt testing-positivity rates and haemodynamics were analysed across age-decade subgroups. Of 5236 investigated patients, 3129 (60%) had a positive TT. Cardioinhibitory responses accounted for 16.5% of positive tests and were more common in younger patients, decreasing from the age of 50-59 years. Vasodepressor (VD) responses accounted for 24.4% of positive tests and prevailed in older patients, starting from the age of 50-59. Mixed responses (59.1% of cases) declined slightly with increasing age. Overall, TT positivity showed a similar age-related trend (P = 0.0001) and was significantly related to baseline systolic blood pressure (P < 0.001). Tilt testing was positive during passive phase in 18% and during nitroglycerine (TNG)-potentiated phase in 82% of cases. Positivity rate of passive phase declined with age (P = 0.001), whereas positivity rate during TNG remained quite stable. The prevalence of cardioinhibitory and VD responses was similar during passive and TNG-potentiated TT, when age-adjusted.

CONCLUSIONS

Age significantly impacts the haemodynamic pattern of TT responses, starting from the age of 50. Conversely, TT phase-passive or TNG-potentiated-does not significantly influence the type of response, when age-adjusted. Vagal hyperactivity dominates in younger patients, older patients show tendency to vasodepression.

Age Is a Predictor for the Syncope Recurrence in Elderly Vasovagal Syncope Patients With a Positive Head-Up Tilt Test

Background: Valid predictors of the syncope recurrence in vasovagal syncope (VVS) patients with a positive head-up tilt test (HUTT) are currently lacking. The goal of this study was to identify the predictive performance of age for the recurrence of syncope in VVS patients with a positive HUTT. Methods: In total, 175 VVS patients with a positive HUTT were observed for 6-32 months, and the recurrence of ≥1 syncope or typical pre-syncope prodromal episodes during follow-up was considered syncope recurrence. The population was divided into 2 groups, namely, a syncope recurrence group (44 patients) and a no syncope recurrence group (131 patients). The baseline clinical data, haemodynamic parameters, and classification of VVS on the HUTT were analyzed. Logistic regression was used to analyse the effect size and confidence interval for age. A receiver operating characteristic (ROC) curve analysis was used to assess the predictive performance and investigate the predictive value of age by the area under the curve (AUC). Results: The median age of the syncope recurrence group was older than that of the no syncope recurrence group [60.0 (47.8, 66.0) years>53.0 (43.0, 62.0) years], and there was a significant difference between the two groups (P < 0.05). The trend for syncope recurrence changed with advancing age, and the logistic regression model adjusted by sex showed that older patients had an increased risk of syncope recurrence in VVS with a positive HUTT [OR value: 1.03, 95% confidence interval (CI): 1.008-1.061, p < 0.05]. Age was a valid predictor for the recurrence of syncope in elderly VVS patients with a positive HUTT (AUC: 0.688; 95% CI: 0.598-0.777, p < 0.05). The cut-off value was 53.5 years, and the sensitivity and specificity were 72.7 and 52.7%, respectively. Conclusions: Age may be a valid predictor for syncope recurrence in elderly VVS patients with a positive HUTT. The rate of syncope recurrence increased with advancing age, especially in females.

Economic value of insertable cardiac monitors in unexplained syncope in the United States

INTRODUCTION

Early use of insertable cardiac monitor (ICM) is recommended for patients with unexplained syncope following initial clinical workup, due to its superior ability to establish symptom-rhythm correlation compared with conventional testing (CONV). However, ICMs incur higher upfront costs, and the impact of additional diagnoses and resulting treatment on downstream costs and outcomes is unclear. We aimed to evaluate the cost-effectiveness of ICM compared with CONV for the diagnosis of arrhythmia in patients with unexplained syncope, from a US payer perspective.

METHODS

A Markov model was developed to estimate lifetime costs and benefits of arrhythmia diagnosis with ICM versus CONV, considering all related diagnostic and arrhythmia-related treatment costs and consequences. Cohort characteristics and costs were informed by original claims database analyses. Risks of mortality, syncopal recurrence, injury due to syncope and quality of life consequences from syncopal events were identified from the literature.

RESULTS

ICM was less costly and more effective than CONV. Most of the observed US$4532 cost savings were attributed to reduced downstream diagnostic testing. For every 1000 patients, ICM was projected to yield an additional 253 arrhythmia diagnoses and lead to treatment in an additional 168 patients. The ICM strategy resulted in overall improved outcomes (0.30 quality-adjusted life years gained), due to a reduction in syncope recurrence and injury resulting from arrhythmia treatment. The results were robust to changes in the base case parameters but sensitive to the model time horizon, underlying probability of syncope recurrence and prevalence of arrhythmias.

CONCLUSIONS

Our model projected that early ICM for the diagnosis of unexplained syncope reduced long-term costs, and led to an improvement in overall clinical outcomes by shortening time to arrhythmia treatment. The cost of ICM was outweighed by savings arising from fewer downstream diagnostic episodes, and the increased cost of treatment was counterbalanced by fewer syncope-related event costs.

Are women really more affected by vasovagal syncope than men?

It is commonly reported that vasovagal syncope (VVS) is more frequent in women. Presently, this issue has never been investigated. The purpose of this review was to evaluate, through an extensive review of the literature, whether women are really more affected by VVS than men. The gender distribution was investigated in individuals with classical and nonclassical VVS. The database PubMed was searched using the terms 'syncope', 'vasovagal syncope', 'neurally mediated syncope' and 'tilt testing'. Twelve studies dealing with classical and 75 with nonclassical VVS were eligible. In the individuals with classical (N = 1861) and nonclassical VVS (N = 9696), a trend towards a greater percentage of women emerged (P = 0.14 and 0.07, respectively). In the total population with VVS (N = 11 557), the percentage of women was significantly higher than that of men (58 versus 42%, P = 0.03). Most of the individuals were young or middle-aged. In 84% of the studies, the percentage of women was greater than that of men. A separate analysis was carried out in older VVS patients (≥60 years) and only two studies were eligible to be evaluated. Considering that almost all the studies were carried out in the western nations, where the number of men and women is almost superimposable until the age of 65 years and a bias by gender has never been reported in the management of VVS, these data strongly suggest that young and middle-aged women are more affected by VVS than their male counterparts. At present, data are too scant to draw a definitive conclusion in older VVS patients.

Isolated very low QRS voltage in the frontal leads predicts recurrence of neurally mediated syncope

BACKGROUND

The study was prompted by our observation that some patients with neurally mediated syncope (NMS) have an isolated QRS complex, of very low voltage (≤0.3 mV cutoff), in 1 of the frontal leads on the 12-lead electrocardiogram.

OBJECTIVE

To prospectively evaluate whether the presence of isolated very low voltage (VLV) predicts recurrence of NMS.

METHODS

We included 205 patients (aged 50 ± 17 years) with a median of 3 syncopal episodes. Tilt testing was performed in all patients and was positive in 87 (42%). The patients were followed for a median of 14 months.

RESULTS

VLV in frontal leads was present in 92 patients (45%). During the follow-up period 60 patients experienced recurrence of syncope. The actuarial total syncope recurrence rate at 1 year was 32% (95% confidence interval [CI 23%-44%) in patients with isolated VLV in frontal plane leads, and 14% (95% CI 8%-24%) in patients without VLV (log-rank test P < .0001). The significant relationship between the presence of isolated VLV in the frontal leads and syncope recurrence was retained in Cox multivariate analysis that included the history of presyncope and syncope as well as the left ventricular end-diastolic diameter. The presence of isolated VLV in frontal leads was associated with a 3-fold increase of the risk of recurrent syncope.

CONCLUSIONS

Isolated very low QRS voltage in the frontal leads predicts recurrence of NMS independent of clinical factors that predict recurrence of syncope in such patients. This phenomenon may help generate new diagnostic tools and insights into the pathogenesis of NMS.

Heart rate recovery and diastolic blood pressure ratio on the treadmill test predict an induction and recurrence of vasovagal syncope

BACKGROUND/AIMS

The induction and recurrence of syncope is a concerning situation that could be unpredicted in the vasovagal syncope (VVS). We investigated a simple predictor for the induced and recurrent VVS during Head-Up table-tilt Test (HUT) and clinically follow-up.

METHODS

The 143 consecutive patients with VVS (age 31 ± 19 years, 33 male) who referred by a cardiologist or neurologist and had undergone an echocardiogram, HUT, and a treadmill exercise test (TMT) were recruited and clinically follow-up. Patients were divided into two groups based on the result of HUT and TMT. The data was analyzed and compared between VVS patients and control 141 patients without VVS who were enrolled in the same study period (age 40 ± 5 years, 117 male).

RESULTS

The heart rate recovery (HRR), recovery systolic blood pressure (RecSBP), recovery diastolic blood pressure (RecDBP), HRR/RecSBP and HRR/RecDBP were significantly different between controls and VVS during the TMT. Within VVS, even if, baseline characteristics were similar between negative and positive HUT (n = 92 vs. n = 51). HRR (31 ± 10 vs. 35 ± 10), HRR/RecSBP (0.24 ± 0.09 vs. 0.28 ± 0.09) and HRR/RecDBP (0.49 ± 0.18 vs. 0.58 ± 0.19) were significantly different between negative and positive HUT results. Especially, HRR/RecSBP and HRR/RecDBP were significantly correlated with induced syncope with a sensitivity and specificity ([60%, 83%] cut-off, 0.31; [72%, 80%] cut-off, 0.63). In the Cox regression, HRR/ RecDBP were significantly associated with recurrence of VVS with hazard ratio of 3.29 (confidence interval, 0.95 to 11.3; p = 0.049).

CONCLUSION

HRR/RecDBP may be a useful predictor for induction during HUT and recurrence during follow-up in the VVS.

Syncope in a Working-Age Population: Recurrence Risk and Related Risk Factors

Syncope in a worker undertaking risky tasks may result in fatalities for the individual or for third parties. We aimed at assessing the rate of syncope recurrence and the risk factors underlying the likelihood of syncope relapse in a working-age population. A prospective cohort of all patients aged 18–65 years consecutively admitted to the Emergency Department for syncope was enrolled. Risk of syncope relapse was assessed at a six-month, 1-year, and 5-year follow-up. Predictors of syncope recurrence have been evaluated at six months and 1 year from the syncope index by a multivariable logistic regression analysis. 348 patients were enrolled. Risk of syncope relapse was 9.2% at 6 months, 11.8% at 1 year, and 23.4% at 5 years. At 6-month follow-up, predictor of syncope recurrence was ≥3 prior lifetime syncope episodes. At 1-year, ≥3 prior lifetime syncope episodes, diabetes mellitus, and anaemia were risk factors for syncope relapse. There was an exceeding risk of recurrence in the first 6 months and a reduced risk of 3.5% per year after the first year. Anaemia, diabetes mellitus, and prior lifetime syncope burden are of importance when giving advice about the resumption of “high risk” jobs following a syncope episode.

Usefulness of Tilt Testing and Carotid Sinus Massage for Evaluating Reflex Syncope

Thirty years ago Tilt Testing (TT) was described as a tool in the diagnostic work-up of vasovagal syncope; after its initial success, some flaws have become evident. The concept of hypotensive susceptibility has provided the test a new relevance, shifting from diagnosis only, to therapeutic management. Carotid Sinus Massage (CSM) was introduced at the beginning of the XX century; the technique has evolved over years, whereas the concept of carotid sinus syndrome (CSS) has remained unchanged and uncontested for more than half a century. Nowadays, CSS is a matter of debate, with new classifications and criteria coming on the scene. Recently, a common central etiological mechanism has been hypothesized for reflex syncope, manifesting as CSS, vasovagal syncope or both. In this context, TT and CSM acquire an important role in clinical practice, being essential for a complete diagnosis and treatment. Recalling their historical background, the present paper illustrates an actual interpretation of TT and CSM.

Renal nerve stimulation for treatment of neurocardiogenic syncope: a review from perspective of commercialization potential

A strong evidence of outcomes for vasovagal syncope is not easily identified. It would seem reasonable that the proposed Mayo Clinic technology would be reserved for cases with severe recurrent or refractory syncope. However, recurrence levels are relatively low, and while some predictive methods have been proposed, recurrence is also influenced by the interaction that occurs during screening and examinations, i.e. recurrence diminishes once an initial diagnosis has been made. Finally, a key factor in being able to identify suitable patients relates to understanding the relative significance of the vasodepression and cardioinhibitory components-the therapy is best suited to patients that have a significant level of both components. It is probably not needed in patients with mainly cardioinhibitory involvement-data from ISSUE 2 and ISSUE 3 studies suggest that this is a relatively large proportion, particularly with asystolic involvement. The challenge remains in having suitable screening tests to identify the best patients. Tilt table testing has questions concerning its ability to replicate clinical syncope-implantable loop recorders (ILRs) may provide more accurate data but their usage is not yet widely accepted given the costs and invasive nature of the monitor.

High Remission Rates in Vasovagal Syncope: Systematic Review and Meta-Analysis of Observational and Randomized Studies

OBJECTIVES

The aims of this study were to quantify the degree of improvement in vasovagal syncope after assessment and to identify predictive factors.

BACKGROUND

No treatments for vasovagal syncope have been proved effective, but patients in all prospective studies appear to show a reduction in the likelihood of fainting.

METHODS

A systematic review and meta-analysis was performed of studies published from 1993 through 2013. Inclusion criteria were: 1) vasovagal syncope frequency in the preceding 1 to 2 years; and 2) the proportion of subjects with syncope in at least the first follow-up year. Random-effects methods were used.

RESULTS

Of 338 screened studies, 17 were analyzed, with a mean of 112 subjects (range 9 to 511 subjects). In the preceding epoch, 97% of subjects fainted, with 2.6 ± 1.0 syncopal spells per year. In the follow-up year, the proportion of patients with ≥1 syncope recurrence was 677 of 1,912 (35.4%), and in the meta-analysis, the proportion of subjects fainting was only 0.44 (95% confidence interval: 0.41 to 0.46; p < 0.001). Subjects in larger studies were less likely to faint than those in randomized trials (relative risk: 0.35 vs. 0.55; p = 0.004). The probabilities of ≥1 syncope recurrence in the observational versus randomized studies were 0.30 (95% confidence interval: 0.24 to 0.37) and 0.54 (95% confidence interval: 0.46 to 0.62), respectively (p < 0.001). None of the degree of blinding, type of intervention, age, sex, and number of recent faints predicted the probability of syncope recurrence. Heterogeneity was very high in all analyses (I² = 60% to 96%).

CONCLUSIONS

The spontaneous remission rate in highly symptomatic syncope patients is high, and remission occurs in all types of studies. Improvement was more likely in larger and observational studies.

Syncope as a health risk for soldiers - influence of medical history and clinical findings on the sensitivity of head-up tilt table testing

BACKGROUND

Syncope is a relevant health problem in military environments. Reliable diagnosis is challenging. Tilt table testing is an important tool for syncope diagnosis. The aim of this study was to determine whether signs such as prodromal symptoms, co-morbidity, frequency of syncopal events, body length, body mass index, and electrocardiography abnormalities can be used to predict the success of tilt table testing at diagnosing syncope.

METHODS

Data from 100 patients with histories of syncope or pre-syncope, who were diagnosed using head-up tilt table testing, were retrospectively analyzed in a cross-sectional analysis. The diagnostic procedure was based upon a modified version of the Westminster protocol without any pharmacological provocation.

RESULTS

Patients showing pathological reaction patterns during tilt table testing suffered from prodromal symptoms, such as dizziness and sweating, significantly more often. The patients reported more injuries resulting from syncopal events and more previous syncopal events, and the prevalence of co-morbidity was greater among patients presenting negative findings during tilt testing. An asthenic-leptosomal physique was not confirmed as a risk factor for syncopal events as is the case for idiopathic arterial hypotension. However, patients with pathological reaction patterns during tilt table testing were significantly taller. This finding was detected for both females and males. No significant predictors were found in the electrocardiogram (ECG) patterns of patients showing syncope during tilt table testing.

CONCLUSIONS

Frequency of prior syncope and prodromal symptoms, and increased body length with an otherwise good state of health influence the predictive value of tilt table testing for syncope diagnosis. In particular, if these factors are present, tilt table testing should be considered part of the diagnostic algorithm for soldiers with recurrent syncope.

Prognostic Value of a Very Prolonged Asystole during Head-Up Tilt Test

BACKGROUND

Clinical significance and prognosis of a cardioinhibitory response to head-up tilt (HUT) test with a very prolonged asystole (≥30 seconds) is poorly studied. Our aim was to evaluate the treatment (including pacemaker implantation) and prognosis (syncope recurrence, syncope-related trauma, and overall mortality) of patients with a very prolonged asystole on a HUT test.

METHODS AND RESULTS

A retrospective study was conducted in two centers between January 2003 and December 2013 and included a total of 2,263 consecutive HUT tests (sensitized with isosorbide dinitrate) performed in 2,247 patients with syncope of unknown etiology. Cardioinhibitory response with asystole was observed in 149 (6.6%) of these tests (44.3% women, mean age 37 ± 18 years old, 16.1% in the nonpharmacological phase), with a median duration of asystole of 10 (6-19) seconds. Very prolonged asystole (≥30 seconds) was documented in 11 (0.5%) patients (45% women; mean age 40 ± 19 years; only one in the nonpharmacological phase, 9 minutes after HUT). The longest pause lasted 63 seconds. In all patients, avoidance of triggering factors and physical counterpressure maneuvers were recommended. Telephone follow-up was performed: in one patient, fludrocortisone was started; tilt training was conducted in one patient and none received a pacemaker. After a median follow-up of 42 (30-76) months, four patients (36%) had syncopal recurrences, one patient had a syncope-related injury (scalp laceration), and no patient died.

Ongoing clinical trials for Vasovagal Syncope: where are we in 2014?

Vasovagal Syncope (VVS) can lead to a markedly diminished quality of life for some patients. While there are many treatments for this condition including physical, mechanical, pharmacologic, and device-based control of heart rate, there are few that have been shown to be effective in randomized clinical trials. In our local experience, we have achieved significant improvement in symptom frequency and quality of life using algorithms based on the data available and on clinical acumen for the majority of patients with VVS. Despite this, there are still many patients who suffer from treatment refractory VVS. Fortunately, there are a number of ongoing clinical trials that are likely to add to our knowledge. Ongoing clinical trials are reviewed to examine new treatment methods for VVS that were listed on public trial registries as of April 15, 2014. Data from these trials should inform future strategies in the care of patients with VVS.

The usefulness of the head-up tilt test in patients with suspected epilepsy

PURPOSE

It is estimated that approximately 20-30% of patients diagnosed with epilepsy have been misdiagnosed, and neurocardiogenic syncope (NCS) might frequently be the real cause of transient loss of consciousness (TLOC) episodes. We assessed the role of the head-up tilt test (HUTT) in patients previously diagnosed with refractory epilepsy to evaluate the ability of this test to correctly diagnose patients with NCS.

METHOD

We retrospectively analysed the clinical records of 107 consecutive patients with a previous diagnosis of refractory epilepsy that were taking antiepileptic drugs and who were referred for HUTT between January 2000 and December 2010. During the subsequent follow-up, we recorded the treatments performed and the recurrence of symptoms.

RESULTS

Complete follow-up data were available for 94 (88%) patients, and the mean follow-up period was 80±36 months. The HUTT was positive in 54% of patients. Thirty-one (33%) patients were misdiagnosed with epilepsy, and 20 (21%) patients had a dual diagnosis of NCS and epilepsy. The recurrence of TLOC was reported in 55% of the patients, but it was significantly lower in the misdiagnosed group (42% versus 64%; P=0.039).

CONCLUSION

NCS is an important cause of epilepsy misdiagnosis. The HUTT is often critical for making an accurate diagnosis and subsequently selecting the appropriate treatment for patients presenting with TLOC. The diagnostic overlap between epilepsy and NCS is not uncommon, suggesting that electroencephalographic monitoring during a HUTT may play an important role in diagnosing patients with recurrent, undiagnosed TLOC episodes.

Management of vasovagal syncope: 2004

Vasovagal syncope is a common disorder that affects at least 20% of people at some time in their lives. Probably half of these patients faint recurrently; for many this causes physical trauma, a substantial reduction in quality of life, and difficulties with driving, employment and education. The last 15 years have seen striking advances in diagnostic approaches and prognostic understanding. A number of physiological, pharmacological and electrical therapies have been developed and tested to various degrees in patients. These include counterpressure manoeuvres, salt and fluid recommendations, and attempted treatment with fludrocortisone, midodrine, beta-blockers, serotonin reuptake inhibitors, and permanent pacemakers. This review highlights the most important of these advances and suggests strategies for managing this often difficult problem.

Clinical Factors Affecting Symptom Recurrence in Patients with Syncope

<b><i>Purpose:</i></b> Recurrent syncope leads to poor functional status and psychiatric impairment in patients with syncope. The aim of the study was to prospectively analyze the risk factors attributed to syncope recurrence. <b><i>Materials and Methods:</i></b> Between 2009 and 2010, 289 patients with all cause of syncope visited our institution. Syncope recurrences were followed for 1 year by telephone interview every 3 months. <b><i>Results:</i></b> We diagnosed 181 (63%) patients with neurally mediated syncope (NMS), 39 (13%) with orthostatic hypotension, 34 (12%) with cardiac syncope, and 35 (12%) with unexplained syncope. During the 1-year follow-up period, 19 (6.6%) patients suffered recurrent syncope. Kaplan-Meier curves showed that recurrent syncope was observed more often in patients with unexplained syncope compared with those with NMS (p < 0.01), and also observed more often in patients with six previous syncopal episodes compared to those with fewer episodes (p = 0.02). Cox regression analysis showed that the recurrence of syncope was significantly associated with more than six previous syncopal episodes (HR 5.38, 95% CI 1.17-24.71, p = 0.03) and that there was a tendency for association between recurrence of syncope and unexplained syncope (HR 6.13, 95% CI 0.96-39.1, p = 0.05). <b><i>Conclusions:</i></b> Patients with previous frequent syncopal episodes or unexplained syncope had higher rates of syncope recurrence during the follow up period.

Near-infrared diffuse optical monitoring of cerebral blood flow and oxygenation for the prediction of vasovagal syncope

Significant drops in arterial blood pressure and cerebral hemodynamics have been previously observed during vasovagal syncope (VVS). Continuous and simultaneous monitoring of these physiological variables during VVS is rare, but critical for determining which variable is the most sensitive parameter to predict VVS. The present study used a novel custom-designed diffuse correlation spectroscopy flow-oximeter and a finger plethysmograph to simultaneously monitor relative changes of cerebral blood flow (rCBF), cerebral oxygenation (i.e., oxygenated/deoxygenated/total hemoglobin concentration: r[HbO2]/r[Hb]/rTHC), and mean arterial pressure (rMAP) during 70 deg head-up tilt (HUT) in 14 healthy adults. Six subjects developed presyncope during HUT. Two-stage physiological responses during HUT were observed in the presyncopal group: slow and small changes in measured variables (i.e., Stage I), followed by rapid and dramatic decreases in rMAP, rCBF, r[HbO2], and rTHC (i.e., Stage II). Compared to other physiological variables, rCBF reached its breakpoint between the two stages earliest and had the largest decrease (76±8%) during presyncope. Our results suggest that rCBF has the best sensitivity for the assessment of VVS. Most importantly, a threshold of ∼50% rCBF decline completely separated the subjects from those without presyncope, suggesting its potential for predicting VVS.

Comparison of incidence, predictors, and the impact of co-morbidity and polypharmacy on the risk of recurrent syncope in patients <85 versus ≥85 years of age

Recurrent syncope is a major cause of hospitalizations and may be associated with cardiovascular co-morbidities. Despite this, prognostic factors and the clinical characteristics among patients are not well described. Therefore, we identified and analyzed data on all patients >50 years of age discharged after a first-time episode of syncope in the period 2001 to 2009 through nationwide administrative registries. We identified the clinical characteristics of 5,141 patients ≥85 years of age and 23,454 patients <85 years of age. Multivariate Cox models were used to assess prognostic factors associated with the end point of recurrent syncope according to age. We found that those with syncope and ≥85 years were more often women (65% vs 47%) and generally had a greater prevalence of noncardiovascular co-morbidities, whereas the prevalence of cardiovascular co-morbidities was more heterogeneously distributed across age groups. Overall, significant baseline predictors of recurrent syncope were aortic valve stenosis (hazard ratio [HR] 1.48, 95% confidence interval [CI] 1.31 to 1.68), impaired renal function (HR 1.34, 95% CI 1.15 to 1.58), atrioventricular or left bundle branch block (HR 1.32, 95% CI 1.16 to 1.51), male gender (HR 1.18, 95% CI 1.12 to 1.24), chronic obstructive pulmonary disorder (HR 1.10, 95% CI 1.02 to 1.19), heart failure (HR 1.10, 95% CI 1.02 to 1.21), atrial fibrillation (HR = 1.09, 95% CI 1.01 to 1.19), age per 5-year increment (HR 1.09, 95% CI 1.07 to 1.10), and orthostatic medications per increase (HR 1.06, 95% CI 1.03 to 1.09). Atrial fibrillation and impaired renal function both exhibited less prognostic importance for recurrent syncope in the elderly compared with younger population (p for interactions <0.01). In conclusion, predictive factors of recurrent syncope were closely associated with increased cardiovascular risk profile age and gender. The use of multiple orthostatic medications additively increased the risk of recurrences representing a need for strategies to reduce unnecessary polypharmacy.

[Diagnostic and prognostic value of the head-up tilt test for patients with unexplained syncope: results of a French survey]

OBJECTIVE

Evaluate the diagnostic and prognostic input of head-up tilt test in the exploration of unexplained syncope.

METHOD

Between January 2009 and December 2012, all patients undergoing a head-up tilt test for recurrent syncope were studied. Follow-up data were obtained using telephone interviews and medical record reviews.

RESULTS

A head-up tilt test was realized in 77 patients (47.8±20years, 53% female) for an exploration of syncope. The tilt test elicited syncope or pre-syncope in 57 patients (74%). The positive response included vaso-vagal syncope in 53 patients and psychogenic syncope in 4 patients. After a mean follow-up of 32±11months (range 6-54months), 90% of patients had not a recurrence of syncope. Of note, the incidence of recurrence was the same regardless of whether the patients had a positive (n=5/48; 10%) or a negative head-up tilt test response (n=2/19; 10%).

CONCLUSION

The tilt test has a certain diagnostic value in the exploration of unexplained syncope. Recurrence rate of syncope after a tilt test is low. However, our study suggests no correlation between head-up tilt test results and the likelihood of recurring syncope.

Clinical laboratory testing: what is the role of tilt-table testing, active standing test, carotid massage, electrophysiological testing and ATP test in the syncope evaluation?

The first step in the diagnostic evaluation of patients with suspected syncope begins with an "initial evaluation" consisting of careful history taking, physical examination including orthostatic blood pressure measurement and electrocardiogram. However, even in expert centers the diagnostic yield of this "initial evaluation" is only approximately 50%. In the remaining cases in which a satisfactory diagnosis is either unknown or uncertain after initial assessment, additional clinical testing is needed. This article reviews the role of some of the more commonly used additional diagnostic tests, including: tilt-table testing, the active standing test, carotid sinus massage, electrophysiological testing, and the adenosine triphosphate (ATP) test. The role of angiography, exercise testing and imaging is noted briefly. Other clinical laboratory investigations, such as ambulatory ECG monitoring, are examined in other papers in this issue. In brief, clinical laboratory tests, carefully interpreted, may be useful in the evaluation of the basis of suspected syncope. However, these tests should be selected carefully and performed based on the pre-test probability inferred from the initial examination, and the less invasive tests should be used first.

Efficacy of lower limb compression in the management of vasovagal syncope--randomized, crossover study

INTRODUCTION

Vasovagal syncope (VS) is the most prevalent cause of transient loss of consciousness. The treatment consists of lifestyle modifications and pacemaker in some patients. The purpose of this study is to evaluate the effect of measures to compress the lower limbs in patients with recurrent episodes of VS submitted to the tilt-test (TT).

METHODS AND RESULTS

Twenty patients, average age 30.5 years (15-75), 13 (65%) female, with a clinical diagnosis of VS and previous TT with a positive result and who had at least one episode of syncope during the last year, were included in this placebo-controlled randomized crossover study. The patients underwent two consecutive TT, at a 1-hour interval, with and without compression by pneumatic compression boots with 40 mmHg at the heels and 30 mmHg for the legs. The blood pressure (BP) and heart rate (HR) of these patients were monitored continuously. The outcome assessors were blinded. The results of the TT were positive in 13 (65%) of the patients in the control groups and in two (10%) of the patients with compression (P < 0.0001). Throughout the test, the systolic BP was not different among the groups. On the other hand, the HR measures showed a difference only in the tilted position at 2 minutes, of 73 ± 16 beats per minute (bpm) in the control group and of 69 ± 16 bpm (P = 0.047) in the compression group.

CONCLUSION

Compression of the lower limbs is very effective to render the TT negative in patients with a diagnosis of VS.

Rationale for the prevention of syncope trial IV: assessment of midodrine

BACKGROUND

Vasovagal syncope is a common problem associated with a poor quality of life, which improves when the frequency of syncope is reduced. Effective pharmacological therapies for vasovagal syncope have been elusive. Midodrine is a pro-drug whose primary metabolite is an alpha-1 adrenoreceptor agonist. A few studies have suggested that it may be beneficial in syncope, but all have had significant methodological limitations. A placebo-controlled clinical trial of midodrine for the prevention of vasovagal syncope is needed.

STRUCTURE OF STUDY

The prevention of syncope trial IV (POST 4) is a multicenter, international, randomized, placebo-controlled study of midodrine in the prevention of vasovagal syncope. The primary end point is the time to first recurrence of syncope. Patients will be randomized 1:1 to receive midodrine 10-30 mg/day or matching placebo, and followed for 1 year. Secondary end points include syncope frequency, presyncope, and quality of life. Primary analysis will be performed with an intention-to-treat approach, with a secondary on-treatment analysis.

POWER CALCULATIONS

A total sample size of 112, split equally between the two groups, achieves 85 % power to detect a 50 % relative risk reduction when the event rates are 55 and 27.5 % in the placebo and midodrine arms. Allowing for 20 % dropout, we propose to enroll 140 patients.

REGISTRATION

POST 4 is registered with http://www.clinicaltrials.gov (NCT01456481).

IMPLICATIONS

This study will be the first adequately powered trial to determine whether midodrine is effective in preventing vasovagal syncope. If it is effective, then midodrine may become the first-line pharmacological therapy for this condition.

Positive result in the early passive phase of the tilt-table test: a predictor of neurocardiogenic syncope in young men

BACKGROUND/AIMS

This study elucidated the prognostic factors for neurocardiogenic syncope in males in their late teens and early twenties.

METHODS

Tilt-table testing (TTT) was performed on 665 males (age range, 17 to 27 years) following the Italian protocol. The subjects were tilted head-up at a 70° angle on a table for 30 minutes during the passive phase. If the passive phase was negative, the subjects were given sublingual nitroglycerin and tilted to the same angle for 20 minutes during the drug-provocation phase. The subjects with positive results were followed without medication. We analyzed factors related to the recurrence rate of syncope.

RESULTS

Of 305 subjects (45.8%) with positive results, 223 (age range, 18 to 26 years) were followed for 12 months. The frequency of previous syncopal episodes ≥ 4 (p = 0.001) and a positive result during the passive phase (p = 0.022) were significantly related to a high recurrence rate. A positive result during the early passive phase (≤ 12 minutes) was significantly related to a higher recurrence rate than was that during the late passive phase (> 12 minutes; p = 0.011).

CONCLUSIONS

A positive result during the early passive phase of TTT and frequent previous syncopal episodes were prognostic factors for neurocardiogenic syncope in men in their late teens and early twenties.

Recent history of vasovagal syncope in a young, referral-based population is a stronger predictor of recurrent syncope than lifetime syncope burden

INTRODUCTION

accurate selection of patients for vasovagal syncope studies requires strong risk stratification and knowledge of the natural history of syncope. We aimed to test the hypothesis that recent history of vasovagal syncope compared to distant history better predicts subsequent recurrence of syncope.

METHODS AND RESULTS

in all, 208 subjects with a positive tilt test and ≥ 3 lifetime syncope spells were followed for 1 year. Syncope episodes in the preceding year and total historical spells were compared for their ability to predict a syncope recurrence using the criteria of optimal statistical significance, best linear separation of risk populations, and impact on power calculations. The number of vasovagal syncope spells in the preceding year better predicted syncope recurrence when compared to total number of historical spells (likelihood ratio statistic 28.4, P < 0.0001; versus 20.4, P = 0.001), and showed a substantial effect as the number of syncope events increased. For example, syncope recurred in 22% of those with <2 spells in the previous year compared to 69% in those with >6 spells. A history of no syncope compared to any syncope in the preceding year was associated with a 1-year probability of 7% versus 46% for syncope recurrence. A study designed to detect a 50% decrease in syncope recurrence at P = 0.05 with 80% power would require 159 patients with at least 3 lifetime spells, and only 108 patients with at least 3 spells in the previous year.

CONCLUSIONS

the number of syncope events in the year preceding clinical evaluation is the best predictor of syncope recurrence.

Comparison of recurrence rate based on the frequency of preceding symptoms in patients with neurocardiogenic syncope or presyncope

BACKGROUND AND OBJECTIVES

In patients with neurocardiogenic syncope or presyncope, symptoms developed unpredictably and intermittently. The purpose of this study was to determine whether there was any significant difference in the recurrence rate of symptoms during the follow-up period between patients with many episodes of symptoms and those with fewer episodes of symptoms before diagnosis, as well as to assess the clinical significance of previous episodes of symptoms during treatment.

SUBJECTS AND METHODS

A total of 100 patients with neurocardiogenic syncope or presyncope were divided in two groups (high episode group, n=54; low episode group, n=46) according to the frequency of symptoms before the head-up tilt test. We retrospectively analyzed the recurrence of symptoms using telephone interviews and medical record reviews.

RESULTS

The clinical characteristics were not significantly different between the two groups. However, the recurrence rate was significantly lower in the high episode group than in the low episode group (5.6% vs. 19.6%, p=0.001). In the high episode group, patients treated with medication showed higher recurrence of symptoms than those without medication. In the lower episode group, a similar result was observed.

CONCLUSION

The frequency of previous symptoms at the diagnosis of neurocardiogenic syncope or presyncope did not predict the occurrence of symptoms during the follow-up period. Therefore, to continue drug treatment based on the frequency of symptoms in patients with neurocardiogenic syncope or presyncope may not be the best option.

Association between psychological complaints and recurrence of vasovagal syncope

PURPOSE

Vasovagal syncope (VVS), the most common cause of transient loss of consciousness (T-LOC), is often accompanied by higher levels of psychological distress. We investigated to what extent psychological complaints interact with the effects of non-pharmacological treatment in patients with frequently recurring VVS.

METHODS

Patients with ≥3 episodes of VVS in the 2 years prior to the start of the study openly received non-pharmacological treatment. Before treatment initiation, we determined the level of general psychological complaints by the Symptom Checklist 90-R (SCL-90-R) questionnaire. We regularly evaluated syncopal recurrence during follow-up. We compared the SCL-90-R scores of VVS patients in our study with the corresponding scores of healthy Dutch subjects (reference population). We examined whether patients with more recurrences during follow-up had higher SCL-90-R scores at baseline and whether this association changed when adjusting for other factors associated with recurrence using logistic regression.

RESULTS

Total SCL-90-R scores were higher in our cohort of patients with frequent episodes of VVS than in the reference population (142 vs. 118; p < 0.001). During the first 6 months of treatment, 42% of patients experienced syncopal recurrence(s). The SCL-90-R scores of these patients were significantly higher compared with patients without syncopal recurrence in this period (160 vs. 130; p = 0.01). After adjusting for other predictors of recurrence, especially the number of episodes before inclusion, the association between SCL-90-R scores and recurrence remained intact.

CONCLUSIONS

Levels of general psychological complaints are higher in patients with syncopal recurrence during non-pharmacological treatment of VVS, even after adjusting for previous syncopal episodes.

Long-term follow-up of patients with syncope evaluated by head-up tilt test

BACKGROUND

Clinicians may be tempted to consider a positive head-up tilt test (HUTT) an unfavorable prognostic indicator. We investigated whether results of routine HUTT predict long-term recurrence of syncope.

METHODS

We analyzed syncope recurrence at long-term among 107 patients (mean age 51 +/- 20 years) receiving HUTT for diagnostic evaluation of unexplained/suspected neurocardiogenic syncope in our Institute.

RESULTS

HUTT was positive in 76 patients (vasodepressive response, n = 58; cardioinhibitory, n = 5; mixed, n = 13). During a median follow-up of 113 months (range, 7-161), 34 (32%) patients experienced recurrence (24 [32%] with positive HUTT during 110 months (7-159); 10 [32%] with negative HUTT during 120 [22-161] months). Actuarial freedom from recurrence at 10 years did not significantly differ for patients with positive/negative test results (after passive/active phases) or with different positive response patterns (vasodepressive, cardioinhibitory, mixed). By contrast, history of >4 syncopes in the 12 months preceding HUTT stratified risk of recurrence, irrespective of HUTT positivity/negativity. At Cox proportional hazards analysis, history of >4 syncopes in the 12 months preceding HUTT was the single independent risk factor for recurrence both in the overall study population (HR, 1.7; 95% CI, 1.07-2.69) and within the subset of patients who tested positive (HR, 1.83; 95% CI, 1.07-3.17).

CONCLUSIONS

This long-term follow-up study reinforces the concept that a positive HUTT should not be considered an unfavorable prognostic indicator; frequency of recent occurrences may be a more valid predictor.

Independent role of reduced arterial baroreflex sensitivity during head-up tilt testing in predicting vasovagal syncope recurrence

AIMS

The involvement of arterial baroreflex function in the pathophysiology of vasovagal syncope (VVS) is controversial, and there are no published data supporting its clinical usefulness. The aim of this study was to evaluate the role of arterial baroreflex sensitivity (BRS) at baseline and during head-up tilt testing (HUT) in predicting the recurrence of VVS.

METHODS AND RESULTS

The study involved otherwise healthy patients with a history of unexplained syncope who underwent diagnostic HUT by being tilted to 70 degrees after 10 min supine rest; the test was potentiated by the administration of 300 microg of nitroglycerine (NTG) after 20 min. Beat-to-beat heart rate and systolic blood pressure were continuously recorded, and the sequence method was used to measure arterial baroreflex control of heart rate. The 190 enrolled patients were followed up for 18 +/- 6 months, during which 34 experienced a total of 90 episodes of syncope recurrence. In a stepwise multivariate analysis, female gender [hazard ratio (HR): 2.74; P = 0.008], the presence of >or=3 syncope events before HUT (HR: 3.36; P = 0.004), and BRS below median value after the start of HUT or after the administration of NTG (HR: 3.79; P = 0.006) were significantly and independently associated with the recurrence of syncope. Moreover, when a BRS value of less than the median was added to the other independent factors in a stepwise model, a significant increase in discrimination (C-index: 0.77) and model fitting (P = 0.001) was observed.

CONCLUSION

Reduced BRS during HUT has independent and incremental value in predicting the recurrence of syncope, thus supporting its potential usefulness in the clinical management of patients.

The autonomic nervous system dysregulation in response to orthostatic stress in children with neurocardiogenic syncope

Neurocardiogenic syncope is a common disorder, which is considered as a benign condition. However, sudden loss of conscience and muscle tone causes anxiety among the family members due to its similarity to sudden death. Autonomic nervous system dysregulation is thought to be responsible in the aetiology. Heart rate variability is used for assessment of autonomic nervous system.We evaluated 24 children between 6 and 18 years (mean plus or minus standard deviation is equal to 12.5 plus or minus 3.28, with neurocardiogenic syncope and 10 healthy controls, mean plus or minus standard deviation is equal to 12.48 plus or minus 3.27) by using 24 hour Holter monitorisation and head-up tilt test. Heart rate variability analysis was performed using the Holter recordings obtained both during head-up tilt test and throughout the day.Our results revealed that, there is no significant difference between the study and the control groups in terms of the mean heart rate and all indices of the heart rate variability (p > 0.05). However, during the first 5 minutes of the head-up tilt test, standard deviation of all RR intervals and root mean square of successive differences were significantly lower in the syncope group compared with the control group, 42.17 plus or minus 12.56 versus 60.10 plus or minus 33.10 and 21.26 plus or minus 8.87 versus 36.80 plus or minus 31.03; p-values 0.02 and 0.03, respectively.In conclusion; autonomic functions in children with neurocardiogenic syncope are similar to healthy children. However, sympathetic hyperactivation occurs during the early phase of orthostatic stress in children with neurocardiogenic syncope comparing to healthy controls. Parasympathetic innervation is not sufficient in compensation of this sympathetic hyperactivation. Management strategy in neurocardiogenic syncope should be based on these pathophysiologic mechanisms.

Syncope while driving: clinical characteristics, causes, and prognosis

BACKGROUND

The risk of syncope occurring while driving has obvious implications for personal and public safety. We aimed to define the clinical characteristics, causes, and prognosis of syncope while driving.

METHODS AND RESULTS

In this case-control study of consecutive patients evaluated for syncope from 1996 through 1998 at an academic medical center, we documented causes, clinical characteristics, and recurrence of syncope while driving. Of 3877 patients identified, 381 (9.8%) had syncope while driving (driving group). Compared with the 3496 patients (90.2%) who did not have syncope while driving, the driving group was younger (P=0.01) and had higher percentages of male patients (P<0.001) and patients with a history of any cardiovascular disease (P=0.01) and stroke (P=0.02). Syncope while driving was commonly caused by neurally mediated syncope (37.3%) and cardiac arrhythmias (11.8%). Long-term survival in the driving group was comparable to that of an age- and sex-matched cohort from the Minnesota population (P=0.15). Among the driving group, syncope recurred in 72 patients, 35 of whom (48.6%) had recurrence >6 months after the initial evaluation. Recurrences during driving happened in 10 patients in the driving group, 7 of which (70%) were >12 months after the initial evaluation.

CONCLUSIONS

In our study, neurally mediated syncope was the most common type of syncope while driving. The causes of syncope, the late recurrences of syncope (during > or =6 months of follow-up), and the overall low incidence of recurrent syncope while driving provide useful information to supplement current recommendations on driving for these patients.

Prevalence, timing, and haemodynamic correlates of prodromes in patients with vasovagal syncope induced by head-up tilt test

AIMS

To evaluate the prevalence, timing, and haemodynamic characteristics of prodromal symptoms in patients experiencing vasovagal syncope (VVS) during a head-up tilt test (HUT) potentiated with nitroglycerin, and their relationships with those reported before spontaneous episodes.

METHODS AND RESULTS

Symptoms preceding HUT-induced syncope were recorded, together with heart rate (HR) and arterial blood pressure (BP) values, in 149 otherwise healthy and drug-free subjects with recurrent unexplained syncope. Head-up tilt test significantly increase the number of patients capable of recognizing the premonitory symptoms of VVS than before spontaneous episodes (96 vs. 79%; P<0.001). The nine most frequent symptoms were stratified into three groups on the basis of their characteristics: headache, hot flashes, and palpitations occurred more than 3 min before syncope, with a very slight reduction in BP; nausea, asthenia, diaphoresis, vertigo, and epigastric discomfort preceded syncope by 1-3 min and were associated with a slight reduction in BP; and blurred vision appeared the last minute before syncope and was characterized by the lowest BP and HR values.

CONCLUSION

In comparison with spontaneous syncopal episodes, HUT allows the more frequent recognition of prodromes also providing useful information in terms of timing and haemodynamic characteristics of symptoms that may allow more tailored patient counselling.