Tilt Test Response Research Articles

The triggers of situational syncope do not influence the head-up tilt test response and prognosis.

The study evaluated the positivity rate, haemodynamic responses, and prognosis in terms of syncopal recurrence among patients with situational syncope (SS) stratified according to the underlying situational triggers. We retrospectively evaluated all consecutive patients with SS who underwent nitroglycerine (NTG)-potentiated head-up tilt test (HUTT) at Syncope Unit of the University of Campania 'Luigi Vanvitelli'-Monaldi Hospital from 1 March 2017 to 1 May 2023. All patients were followed for at least one year. The study population was divided according to the underlying triggers (micturition, swallow, defaecation, cough/sneeze, post-exercise). Two hundred thirty-six SS patients (mean age 50 ± 19.3 years; male 63.1%) were enrolled; among them, the situational trigger was micturition in 109 patients (46.2%); swallow in 32 (13.6%) patients; defaecation in 35 (14.8%) patients; post-exercise in 41 (17.4%) patients; and cough/sneeze in 17 (7.2%) patients. There were no significant differences in baseline clinical characteristics and HUTT responses between different situational triggers. The Kaplan-Meier analysis did not show a statistically different rate of syncope recurrence across patients stratified by baseline situational triggers (log-rank P = 0.21). Situational syncope appears to be a homogenous syndrome, and different triggers do not impact the HUTT response or syncope recurrence at 1 year.

Sex and age differences in clinical presentation and head-up tilt test results in patients with vasovagal syncope

Abstract Background Previous evidence indicates important sex- and age-specific characteristics of vasovagal syncope (VVS), which may be relevant to diagnostic and therapeutic approaches. Purpose To investigate differences in presentation, symptoms, and head-up tilt test (HUTT) response in patients with VVS based on biological sex and age groups. Methods This study analyzed data from the HUTT registry at a tertiary syncope unit between 2017 and 2022, including adults aged 18 years or older who were diagnosed with VVS. The diagnosis was based on clinical criteria, and conformed with the latest syncope guidelines. Clinical features and head-up tilt test results were recorded and analyzed to understand the sex and age-specific characteristics of VVS. HUTT was performed using an electrically-controlled tilt table, with continuous hemodynamic monitoring, according to the Italian protocol. The type of response to HUTT was decided according to the Vasovagal Syncope International Study (VASIS) criteria, and HUTT was only considered positive if syncope occurred during the test. Results Among 1,914 eligible patients, 49% were female, and the mean age was 46.43 ± 17.77. Male participants were significantly older (44 vs 49 years of age, P<0.001), and had higher rates of diabetes mellitus (10% vs 7%) and hypertension (25% vs 19%), while female patients had a higher prevalence of anemia (24% vs 11%). There was a non-significant trend for more emergency department visits among males (7% vs 5%). Females were more likely to experience prodromal symptoms such as nausea and abdominal discomfort, typical cutaneous symptoms, and less typical prodromes like aura. Compared to males, female patients were also more likely to report specific triggers, which helps establish the diagnosis of VVS and makes avoidance of triggers possible. On the other hand, females were more likely to experience seizure-like movements, and experienced more post-syncopal symptoms. The head-up tilt test results were not significantly different based on sex (Figure 1). Younger patients were more likely to experience specific triggers and manifest prodromal symptoms, compared to older individuals, which highlights the challenges for diagnosis of VVS in older age. In contrast, younger patients with VVS were more likely to present with seizure-like movements and abnormal gaze during the VVS episode. There was a non-significant trend for higher rates of urinary incontinence during VVS among older patients. Older patients were less likely to have a cardioinhibitory response during HUTT, which confirms findings from previous studies (Figure 2). Conclusion The present study highlights the differences in the clinical presentation of VVS based on sex and age, providing valuable information for diagnosis and management of this condition. Further studies are needed to understand the mechanisms behind these differences and to develop tailored treatment plans for VVS.

Head up tilt test response patterns in patients undergoing cardioneuroablation

Abstract Funding Acknowledgements Type of funding sources: None. Background Vasovagal syncope (VVS) is the most common cause of transient loss of consciousness. It severely affects quality of life and can often lead to severe trauma and fatal accidents. Effective treatment of some of these patients can be obtained with cardioneuroablation (CNA). Head-up tilt test (HUT) plays a major role during the evaluation of syncope patients and helps to differentiate syncope subtypes. Data on the HUT response patterns and its usefulness for the recommendation of CNA and the evaluation of the results is lacking. Purpose To assess HUT response patterns before and after CNA. Methods We included patients with repetitive episodes or considered clinically relevant episodes of vasovagal syncope in the previous 6 months and symptomatic patients with documentation of functional sinus bradycardia or functional AV node block. Before performing CNA, all patients underwent a comprehensive baseline evaluation to analyze sinus node and AV node function. CNA was considered in those patients in whom intrinsic sinus node or AV node disease has been excluded in the electrophysiological study (response to atropine was also assessed), had a VASIS type 2A, 2B or type 1 (mixed) response to the HUT and provided signed informed consent. CNA was performed under general anesthesia and ablation strategy was based on presumed anatomical localization of GP. Follow-up of these patients was performed in the outpatient clinic with scheduled visits at 1, 6 and 12 months including 24-hour Holter monitoring. A control HUT was performed at 3 months. Results We included 36 patients. 22 males (61.1%), mean age 51 (18-82 years). The average number of syncope events per year per patient prior to the procedure was 5 ±3. The mean HR on Holter Pre CNA was 65 ± 12 and 72 ± 9 post CNA. Of the HUT, 9 (25%) had mixed type response; 9 (25%) cardioinhibitory type 2A and 18 (50%) cardioinhibitory type 2B. The response in type 2B was sinus arrest in 12 (33.3%), AV block in 5 (13.9%) and both in 1 (2.8%) patient. During a mean of 9 ±4 months follow-up, only 3 patients had a syncope recurrence. At the three-month HUT we observed complete elimination of the cardioinhibitory component present prior to CNA in 34 (94.4%) patients. During the HUT, 18 (50%) had no syncope whereas the remaining 17 had HUT-induced syncope. In 16 (44.4%) of them due to vasodepressor mechanism and only 1 due to cardioinhibitory type 2A response (Figure 1). This patient also had a syncopal recurrence in the follow up. We did not perform the control HUT in 1 patient because of an early recurrence and the patient decided to undergo a pacemaker implantation. We had another recurrence at 11 months post CNA in a patient in whom the control tilt test was negative. The syncope-free survival curve can be seen in Figure 2. Conclusions CNA changes the response pattern of the HUT by eliminating the cardioinhibitory component and can be useful in the evaluation of the long-term CNA outcomes.

The clinical presentation of syncope influences the head-up tilt test responses

Little is still known about the positivity rate of nitroglycerin (NTG) potentiated head-up tilt test (HUTT) according to the history-based clinical features of syncope. The study aimed to compare the HUTT positivity rate and type of responses in patients with classical and non-classical vasovagal syncope (VVS). We retrospectively evaluated all consecutive patients who underwent NTG-potentiated HUTT for VVS. The study population was dichotomized into classical and non-classical VVS. A total of 1285 VVS patients (45± 19.1 years; 49.6% male) were enrolled: 627 (48.8%) had a history of classical VVS and 658 (51.2%) of non-classical VVS. HUTT was positive in 866 (67.4%) patients. The positivity rate was significantly higher in patients with classical compared to those with non-classical VVS (81.5% vs 54%; P< 0.0001). Cardioinhibitory response showed similar total positivity rate (27.6% vs 31%; P= 0.17), but higher relative prevalence among positive tests (57.7% vs 33.9%, P< 0.0001) in patients with non-classical VVS. At multivariable analysis, classical reflex syncope, male sex, history of traumatic syncope and use of diuretics were independent predictors of HUTT positivity. The clinical presentation of syncope influences the overall HUTT positivity rate and the type of responses. Cardioinhibitory response and traumatic syncope are more likely in patients with non-classical VVS.

Patients with reflex syncope have a higher prevalence of atrial fibrillation than general population which is predicted by the type of the tilt table test response

Abstract Introduction Reflex syncope is the result of an imbalance between the sympathetic and parasympathetic nervous system. The autonomic nervous system has been associated to some forms of atrial fibrillation (AF). Objective The aim of this study was to assess the prevalence of AF in patients with reflex syncope and a positive tilt table test and to identify the type of tilt test response in patients with AF in comparison to patients without AF. Methods We retrospectively studied consecutive patients that underwent a tilt table test at our institution between 2016 and 2019. We selected those patients with a positive test. Patients with an implanted pacemaker at the time of the tilt test and patients followed in a different institution were excluded. Previous diagnoses of AF episodes were assessed. We analysed the clinical characteristics and the tilt table test results according to previous history of AF. Results We studied 49 patients with a positive tilt test. Seven (14.3%) patients had previously diagnosed paroxysmal AF at the time of the tilt table test. Patients with AF were older, had more frequently hypertension, and the tilt test response was more frequently a vasodepressor than mixed or cardioinhibitory response (71.4% vs. 28.6%) (Table). In univariate analysis, age and hypertension were associated with AF, respectively, OR 1.08 (95% CI 1.01–1.17), p=0.034 and OR 10.80 (95% CI 1.19–98.36), p=0.035. A vasodepressor response was also associated with AF (OR 6.25, 95% CI 1.06–36.74, p=0.043). Conclusions Patients with reflex syncope and a positive tilt table test had a higher prevalence of AF than the general population. A vasodepressor response was associated with AF as were age and hypertension, demonstrating the possible impact of the autonomic nervous system and the multifactorial nature of AF. Funding Acknowledgement Type of funding sources: None.

The impact of total sleep deprivation upon supine and head up tilt hemodynamics using non-linear analysis in firefighters

PurposeThe impact of 31 h of total sleep deprivation (TSD) on cardiovascular autonomic modulation was evaluated in 46 volunteers all professional fire brigade units officers (all men, mean age = 32.11 ± 6.4). MethodsHemodynamic examination was obtained at baseline and after 31 h of Total Sleep Deprivation (TSD). Each measurement period included supine and head-up tilt (HUT) test response. Continuous beat-to-beat systolic blood pressure (sBP), diastolic blood pressure (dBP) and mean blood pressure (mBP), heart rate (HR), stroke volume (SV), left ventricular ejection time (LVET) and cardiac output (CO) were calculated in rest supine position and in response to HUT. Nonlinear analyses were conducted using Permutation Entropy (PE), Amplitude Aware Permutation Entropy (AAPE) and Fractal Dimension (FD). ResultsSupine increase of HR and decrease in RRI, LVET and entropy of LVET were observed after 31-h of TSD. Increase in entropy of mBP was indicated by AAPE and PE methods. Response to HUT, values of spectral analysis of blood pressure (normalized units of high frequency of sBP and dBP) was altered. Permutation entropy of mBP in response to HUT were significantly changed after 31-h of TSD. ConclusionsTSD alters autonomic nervous system modulation of cardiac and vascular functioning while supine and in response to orthostatic stress. TSD resulted in changes in cardiac and both spectral and two methods of analysis of entropy of blood pressure when supine. Values of spectral analysis of blood pressure and permutation entropy of mean blood pressure in response to HUT were significantly changed after 31 h of TSD.

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

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. 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. 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.

Symptom Score: A New Instrument to Assess Orthostatic Intolerance in Children and Adolescents.

To develop an orthostatic intolerance symptom scoring system to assess orthostatic intolerance and then to compare the symptom score among different head-up tilt test responses. 272 subjects (5-18 years) presenting with orthostatic intolerance symptoms finished questionnaire and head-up tilt test. According to head-up tilt test hemodynamic responses, the subjects were divided into head-up tilt test negative, vasovagal syncope, and postural tachycardia syndrome groups. We built up a symptom score according to the frequency of dizziness, headache, blurred vision, palpitations, chest discomfort, gastrointestinal symptoms, profuse perspiration, and syncope. The median score in postural tachycardia syndrome subjects was highest. A score of 2.5 for predicting vasovagal syncope yielded a sensitivity of 75.0% and specificity of 50.3%, a score of 5.5 for predicting postural tachycardia syndrome yielded a sensitivity of 69.7% and specificity of 72.0%. Furthermore, the median score in postural tachycardia syndrome subjects was significantly higher than that in head-up tilt test negative subjects with heart rate increment of 30-39 beats/min (P < .01). This suggests that the symptom score has some predictive value in head-up tilt test results, which can be served as a preliminary assessment instrument.

Duration of treatment with oral rehydration salts for vasovagal syncope in children and adolescents.

Oral rehydration salt (ORS) is a first-line medication for vasovagal syncope (VVS) in children and adolescents. We retrospectively investigated the treatment with ORS-I (Na 90 mmol/L) for VVS in children and adolescents to define appropriate duration of treatment. All patients with a diagnosis of VVS, based on the first head-up tilt test (HUTT) response, and who accepted ORS-I treatment were enrolled. ORS was stopped when the HUTT response turned negative. Patients were followed for six months after cessation of ORS treatment. The study group included 129 patients (57 male, 72 female; mean age, 11.8 ± 2.0 years, age range, 7.0- 17.0 years). Median duration of VVS was 4 months (range, 1 week to > 10 years). The number of syncope ranged from 2 times to > 20 times. Mean follow-up time was 27.8 ± 6.9 weeks (range, 26-33 weeks). It took to 2~13 weeks for HUTT response to turn negative, with an average time of 8.4 weeks (95% confidence interval, 6.89~9.84 weeks). There was no statistical difference for the time to negative HUTT response according to age groups ( < 12-year-old vs. ≥12-year-old), syncope type (vasodepressor vs. mixed), and the syncope frequency. No patient experienced syncope after cessation of ORS treatment. Our findings suggest that ORS-I is an effective measure to treat children and adolescents with VVS. We recommend a treatment course of 2 months.

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.

Diagnostic role of head-up tilt test in patients with cough syncope.

The aim of this study was to describe the head-up tilt (HUT) test and carotid sinus massage (CSM) responses, and the occurrence of syncope with coughing during HUT in a large cohort of patients. A total of 5133 HUT were retrospectively analysed to identify patients with cough syncope. Head-up tilt followed by CSM were performed. Patients were made to cough on two separate occasions in an attempt to reproduce typical clinical symptoms on HUT. Patients with cough syncope were compared with 29 age-matched control patients with syncope unrelated to coughing. A total of 29 patients (26 male, age 49 ± 14 years) with cough syncope were identified. Coughing during HUT reproduced typical prodromal symptoms of syncope in 16 (55%) patients and complete loss of consciousness in 2 (7%) patients, with a mean systolic blood pressure reduction of 45 ± 26 mmHg, and a mean increase in heart rate of 13 ± 8 b.p.m. No syncope or symptoms after coughing were observed in the control group. The HUT result was positive in 13 (48%) patients with the majority of positive HUT responses being vasodepressor (70% of positive HUT). Carotid sinus massage was performed in 18 patients being positive with a vasodepressor response causing mild pre-syncopal symptoms in only 1 patient. Syncope during coughing is a result of hypotension, rather than bradycardia. Coughing during HUT is a useful test in patients suspected to have cough syncope but in whom the history is not conclusive.

Which hemodynamic parameter predicts nitroglycerin-potentiated head-up tilt test response?

The aim of our study was to identify the early hemodynamic predictors of head-up tilt test (HUTT) outcome in healthy patients with recurrent unexplained syncope. The study involved 95 patients (mean age 38 ± 15; 42 male) who were referred for the evaluation of the syncopal episodes from October 2012 to May 2013. According to the nitroglycerin-potentiated diagnostic tilt test response, the study population was divided into two groups: HUTT+ Group (61 patients, mean age 37 ± 10; 27 male) and HUTT- Group (34 patients, mean age 38 ± 11; 15 male) with no tilt-induced syncope. Finger arterial blood pressure (BP) was recorded during tilt testing. Left ventricular stroke volume (SV), cardiac output (CO), and total peripheral resistance (TPR) were computed from the pressure pulsations. After nitroglycerin administration, the HUTT+ Group showed a significant increase in heart rate (92.0 ± 7.3 beats/min vs 68.9 ± 8.7 beats/min, P < 0.0001), with well-maintained systolic BP (111.6 ± 14.1 mm Hg vs 108.8 ± 11.5 mm Hg; P = 0.332) and diastolic BP (66.1 ± 8.5 mm Hg vs 63.1 ± 6.9 mm Hg; P = 0.0913); a significant decrease in SV (53.9 ± 8.0 mL vs 78.6 ± 8.2 mL; P < 0.0001) and CO (4.0 ± 0.5 L/min vs 5.8 ± 1.0 L/min; P < 0.001), and a significant increase in TPR (1.3 ± 0.3 U vs 0.9 ± 0.2 U, P < 0.0011). We tested three hemodynamic parameters (SV, CO, and TPR) as predictors of positive tilt test response with receiver-operating characteristic curve analysis. Our results show that, 2 minutes after nitroglycerin administration, a statistically significant decrease of SV values (<67 mL) strongly predicts (area under the curve, 0.985; P < 0.0001) the HUTT-positive response in healthy patients with recurrent unexplained syncope.

Autonomic dysfunction in chronic persistent dizziness

ObjectiveTo investigate the autonomic dysfunction in patients with chronic persistent dizziness using standardized autonomic function tests. MethodsWe prospectively recruited 18 patients with chronic persistent dizziness after excluding other causes with extensive investigations. A standardized battery of autonomic tests including the head up tilt (HUT) test, Valsalva maneuver (VM), and heart rate (HR) response to deep breathing was performed. ResultsApproximately eighty percent of the patients showed at least one abnormality in autonomic tests. Two patterns of autonomic abnormality were identified: sympathetic failure, including abnormal decrease in blood pressure (BP) during HUT test or abnormal sympathetic indices related with the BP recovery during late phase II and phase IV during VM, and sympathetic hyperactivity, including abnormal increase in HR response during HUT test or an exaggerated phase IV response manifesting increased β-adrenergic tone during VM. ConclusionsAutonomic dysfunction is frequently found in patients with chronic persistent dizziness after excluding other causes with extensive investigations. Sympathetic failure or hyperactivity may be postulated as one of the possible causes of chronic persistent dizziness. Clinicians should be aware of the possibility of autonomic dysfunction in patients with chronic dizziness, even if the dizziness is not orthostatic but persistent.

Résultats diagnostiques à court terme et pronostiques à long terme chez des patients avec syncopes inexpliquées : résultats d’un série menée en centre hospitalier

ObjectiveEvaluate the diagnostic and prognostic input of head-up tilt test in the exploration of unexplained syncope. MethodBetween 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. ResultsA 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%). ConclusionThe 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.

Predicting Recurrence of Vasovagal Syncope: A Simple Risk Score for the Clinical Routine

Predictors for recurrence of syncope are lacking in patients with vasovagal syncope. The aim of this study was to identify risk factors for recurrence of syncope and develop a simple prognostic risk score of clinical value. Two hundred seventy-six patients with a history of vasovagal syncope were prospectively followed for 2 years. Diagnosis of vasovagal syncope was based on clinical history and negative standard work-up. Inclusion in the study was independent from the result of the head-up tilt test, which was performed in all cases. Risk factors for syncope recurrence were evaluated by the Cox proportional hazards regression model and implemented in a risk score, which was validated with the log-rank test and an internal cross-validation. The Cox-regression analysis identified the number of previous syncopal events, history of bronchial asthma, and female gender as predictors for syncope recurrence (all P < 0.05). In contrast, head-up tilt test response had no predictive value (P = 0.881). Developing a risk score, study patients were identified as having high (recurrence rate during 2 years of follow-up: 37.2%), intermediate (24.8%), and low (6.5%) risk for syncope recurrence (receiver operating characteristic [ROC] of score 0.83, P < 0.01; Log-rank test for event-free survival, P < 0.005). In patients with vasovagal syncope, risk of recurrence can be stratified and is predictable based on a simple risk score.

Neurally Mediated Susceptibility in Individuals with Brugada‐Type ECG Pattern

Neurally mediated syncope and Brugada syndrome (BS) share common pathophysiologic mechanisms related to autonomic nervous system modulations, and particularly with increased vagal tone. This study aimed to investigate the incidence of neurally mediated susceptibility in individuals with Brugada-type electrocardiogram (ECG) pattern. Eight asymptomatic male individuals (mean age 41.6 +/- 10.6 years) with spontaneous or procainamide-induced type 1 ECG pattern of BS and structurally normal hearts underwent a drug-free head-up tilt test. Twenty-five healthy male subjects (mean age 37.4 +/- 14.1 years) with normal ECG and without structural heart disease were included in the study, and served as comparative controls. A positive tilt test response was observed in three out of eight subjects with the Brugada-type ECG pattern (37%) and in three out of 25 controls (12%) (P = 0.018). This study demonstrates a high incidence of neurally mediated susceptibility in asymptomatic individuals with Brugada-type ECG pattern. Severe diagnostic and therapeutic dilemmas may rise from this coexistence. A positive tilt test in subjects with Brugada-type ECG displaying a history of syncope may mislead the physician to a false sense of security. Further studies are required to validate our findings and possibly evaluate the role of tilt test in risk stratification of patients with BS.

Is Home Orthostatic Self‐Training Effective in Preventing Neurally Mediated Syncope?

Repeated orthostatic stress may prove to be of benefit in the regulation of neurally mediated syncope. But the role of home orthostatic self-training is not established to prevent symptoms in patients with neurally mediated syncope. We performed a prospective and randomized study to evaluate the effectiveness of repeated home orthostatic self-training in preventing tilt-induced neurally mediated syncope. Fourty-two consecutive patients (24 males and 18 females, mean age 39 years, 16-68 years) with recurrent neurally mediated syncope were randomized into the tilt training and control groups. The home orthostatic self-training program consisted of daily sessions for 7 days a week for 4 weeks. In order to determine the effects of home orthostatic self-training, we repeated the head-up tilt test in both groups 4 weeks later. Among the tilt-training group, 9 of 16 patients (56%) had a positive response on follow-up head-up tilt test. Among the untreated control group, 9 of 17 patients (53%) had a positive response on follow-up head-up tilt test. In subgroup analyses according to the number of tilt-training sessions or the classified type, we found no differences in the follow-up head-up tilt test responses. Spontaneous syncope or presyncope over mean follow-up of 16.9 months were observed in 42.9% versus 47.1% in the tilt-training and control group, respectively. Home orthostatic self-training was ineffective in reducing the positive response rate of head-up tilt test in patients with recurrent neurally mediated syncope.

Elderly patients with unexplained syncope: What should be considered a positive tilt test response?

Introduction Syncope is a common problem and can lead to serious consequences in the elderly. Tilt test is useful to investigate recurrent syncope, but few studies have investigated the hemodynamic responses of this population to tilt test. Objective To describe the tilt test responses of elderly patients with recurrent syncope of unknown origin and to determine the occurrence of altered cardiovascular autonomic function in a subset of those with the diagnosis of dysautonomic pattern to the tilt test. Methods Elderly patients ( n = 165; > 60 years old) who sought medical assistance because of recurrent syncope during 18 months were initially enrolled and submitted to a two-stage, nitroglycerin-potentiated tilt test. A subset of patients who presented with dysautonomic response to tilt test performed clinical autonomic tests. Results The most frequent cause of syncope during tilt test was the dysautonomic pattern (43%), followed by mixed type neurocardiogenic syncope (35%). Most patients who remained asymptomatic during tilt test showed clear abnormal hemodynamic response during the exam. Conclusion Autonomic dysfunction, which can be found during tilt test, is probably an important cause of syncope in the elderly, regardless of the occurrence of symptoms during the tilt test.

Analysis of Head-Up Tilt Test Responses in Patients Suffering From Syncope and High Blood Pressure

We studied the difference in head-up tilt test responses between patients suffering from syncope who had hypertension and those who did not. A total of 338 consecutive patients with syncope underwent head-up tilt testing in our department from January 2003 to October 2004. Of these, 243 did not have hypertension (group A), whereas 95 did (group B). There were significant differences between the groups in age (P=.0001), sex (P=.048), timing of syncope development (P=.0001), and prevalence of diabetes mellitus (P=.0001). The head-up tilt test gave positive results in 168 patients (69.1%) in group A and in 63 (66.3%) in group B (P=.6; NS). There was no significant difference between the groups in the proportion of positive responses that occurred in either the baseline or nitroglycerin-enhanced phase of the test (P=.673; NS), nor in the time to onset of syncope in either phase (P=.69; NS, and P=.28; NS, respectively). However, there was a significant difference in the type of response (vasodepressor response, 33% in group A versus 49% in group B, P=.01). In the multivariate analysis, no independent variable was found to be associated with the result of the head-up tilt test.

Clinical and subclinical autonomic dysfunction in chronic inflammatory demyelinating polyradiculoneuropathy

Autonomic neuropathy, although common in Guillain-Barré syndrome, is considered rare in chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) and has not been systematically investigated in that disorder. The present study was aimed at determining the prevalence of autonomic dysfunction and investigating the integrity of autonomic nervous system (ANS) reflexes in CIDP. We studied 17 patients with idiopathic CIDP and 20 healthy controls. Six quantitative autonomic function tests (AFTs) were used: Valsalva ratio, 30/15 ratio, and inspiration-expiration difference for parasympathetic function; and tilt test, handgrip test, and sympathetic skin response for sympathetic function. Eleven patients had symptoms of autonomic dysfunction. AFTs were abnormal in 13 patients. Parasympathetic and sympathetic systems were affected with equal frequency. The tilt test was abnormal most frequently, followed by the 30/15 ratio. Three patients developed postural hypotension with loss of consciousness during the tilt test. Abnormality of AFTs did not correlate with the presence of dysautonomic symptoms; duration, severity, and clinical course of the disease; or with age or gender of patients. Our study suggests a higher frequency of clinical and subclinical involvement of the ANS in CIDP than previously estimated. Dysautonomic symptoms are frequent but are mild. However, upon prolonged passive standing, autonomic failure can lead to loss of consciousness. The subclinical involvement of the ANS affects mainly the sympathetic vasomotor and parasympathetic cardiovascular fibers.