Syncope Group Research Articles

558 The assessment of myocardial function in young and elderly syncopal patients using non-invasive impedance cardiography during tilt testing

Non-invasive impedance cardiography (ICG) is a useful predictor of decompensation in heart failure management and critical care. We sought to utilise this modality to assess for age related differences in myocardial function in young and elderly patients with reflex or neurally mediated syncope during tilt testing. All patients fulfilled our inclusion criteria; age over 16 years old, with 2 or more unexplained syncopal episodes in the last 2 years, absence of co-morbidities requiring hospitalisation. Patients attended a syncope clinic for initial assessment and investigations followed by tilt testing. Head up tilting (HUT) was performed according to the Italian protocol. Measurements were recorded until the point of syncope for each patient. Patients were classified as young (below 70 years old) and elderly (above 70 years). Between 2008 and 2009, 108 patients underwent HUT. 43 patients (25 female) were diagnosed with neurally mediated syncope. All patients experienced syncope during the GTN phase of HUT except 3 from the young group and 1 from the elderly group. At baseline stroke index (SI) was low in both young and elderly groups (normal 60-120 ml/m3), but significantly lower in the elderly cohort (mean ± SD, 43.3 (12.2) and 36.3 (7.5) ml/m2; respectively, P = 0.03). The differences ceased to be significant as HUTT progressed but SI remained low and was markedly decreased compared to initial values at the point of syncope in both groups. Baseline end diastolic index (EDI) values were elevated in both groups and was significantly higher in the younger patients (70 (18.4) ml/m2 in the young, 57.1 (11.2) in the elderly, P = 0.009). At point of syncope both groups again experienced a marked decrease although the difference at this stage was non-significant. In the elderly, the cardiac index (CI) and left ventricular work index (LVWI) were significantly lower than the younger group from the start of HUT through to syncope although not at baseline. Both groups demonstrated an inability to maintain baseline cardiac output and left ventricular work over time, with significantly lower measurements in the elderly. There appeared to be an elevated left ventricular pre-load status in these vaso-vagal patients at rest.

Syncopal migraine

A subgroup of syncope patients report migraine headaches immediately preceding or following syncope, and some respond to anti-migrainous prophylactic agents. This study aimed to describe the frequency of migrainous features concurrent with episodes of syncope and to propose clinical criteria for assessing whether a migrainous mechanism might underlie syncope. This retrospective, questionnaire-based study developed criteria for syncopal migraine based on the International Classification of Headache Disorders II (ICHD-II) migraine criteria. Two hundred and forty-eight recurrent syncope subjects (>3 episodes) were stratified based on the presence (N=127) or absence (N=121) of a headache concurrent with syncopal episodes. Syncopal headaches were classified as either syncopal migraine (meeting ICHD-II criteria for migraine or probable migraine, without aura) or nonspecific (not meeting the criteria for syncopal migraine). The syncope groups were then compared to 199 subjects with migraine headaches using chi-square and Cochran-Armitage test for trend. Nearly one-third of recurrent syncope subjects met criteria for syncopal migraine. This group resembled the migraine headache population more than the syncope population in age, gender, autonomic testing, and comorbid conditions. The syncopal migraine group also reported a longer duration of syncope and a longer recovery time to normal. Finally, anti-migrainous medications reduced syncope in half of the syncopal migraine subjects. Syncope may have a migrainous basis more commonly than previously suspected, and we suggested criteria to identify these patients. Syncopal migraine appears epidemiologically more closely related to migraine than to reflex syncope.

Dreaming experience as a useful diagnostic clue for syncopal episodes

The differential diagnosis between epileptic seizures and syncopes is a common occurrence in clinical practice. The manifestations of seizure and syncope sometimes overlap, and available diagnostic testing often not provides a conclusive answer. Syncope is often preceded by a symptom complex characterized by lightheadedness, generalized muscle weakness, giddiness, visual blurring, tinnitus, and gastrointestinal symptoms. These subjective symptoms are very important in guiding the diagnosis. In our experience, the impression of coming out of a dream after the syncopal episode is a subjective symptom commonly reported by patients, if questioned. To verify the occurrence of dreaming experience after syncope and after generalized tonic-clonic seizures (GTCS) and its diagnostic value in differential diagnosis, we asked 100 patients with GTCS and diagnosis of idiopathic generalized epilepsy (Group 1) and 100 patients with a certain diagnosis of syncope (Group 2) whether they have never felt the impression of coming out of a dream after the loss of consciousness (GTCS or syncope, respectively). In Group 1, nobody referred the dreaming experience, whereas in the syncope group, 19% of patients referred this subjective symptom. Dreaming experience seems to be an additional useful diagnostic clue for syncopal episodes, helping the clinician to differentiate them from seizures.

Routine or Protocol Evaluation of Trauma Patients With Suspected Syncope is Unnecessary

Syncope is a commonly suspected cause of injury. Patients often undergo extensive testing without proven benefit. In this study, we investigated the utility of an inpatient syncope workup. A retrospective review was performed of all admissions to a Level I trauma center after fall or motor vehicle collision in patients older than 50 years and in whom syncope was suspected for the 3-year period ending December 2008. Demographics, diagnostic workup, number of abnormal results, and the frequency of subsequent interventions were recorded. Two thousand one hundred seventy-one patients fulfilled study entry criteria; syncope was suspected in 302. The syncope and nonsyncope groups, respectively, were similar in age (76.9 years±12 years vs. 74.8 years±13 years) and female gender (58.3% vs. 58.4%) but differed in Injury Severity Score (7.4±5.7 vs. 9.7±7.7; p<0.01). Diagnostic workup commonly included electrocardiogram (89.4%), cardiac enzymes (88.7%), echocardiogram (78.8%), and carotid duplex or computed tomography angiography (64.9%). Significant abnormal results were uncommon: cardiac enzymes (2.9%), echocardiogram (3.8%), and carotid imaging (4.6%). Overall only 42 patients (13.9%) required further intervention, and in 29 patients (69%), the intervention was based on the initial history, physical examination, or admitting electrocardiogram. Routine inpatient syncope workup has a low yield. Our data suggests that the diagnostic workup should be ordered based on clinical information rather than a standardized workup for all patients with suspected syncope.

Fragmented QRS is associated with torsades de pointes in patients with acquired long QT syndrome

Acquired long QT syndrome (LQTS) is a disease due to a secondary repolarization abnormality induced by various predisposing factors. In contrast to congenital LQTS, risk factors that produce acquired LQTS include organic heart diseases that often exhibit depolarization abnormality. Although various repolarization parameters have been evaluated in acquired LQTS, the existence of depolarization abnormality in association with torsades de pointes (TdP) has not been reported. The purpose of this study was to evaluate both repolarization (QT components) and depolarization parameters (fragmented QRS [fQRS]) in acquired LQTS patients with markedly prolonged QT interval. Seventy patients with acquired severe QT prolongation (QTc ≥ 550 ms) were studied. Thirty-two patients had syncope or TdP (syncope group). Thirty-eight patients did not have any symptoms (asymptomatic group). The existence of fQRS and QT components (QT, QTc, Tpe [interval between peak and end of T wave] intervals, and U-wave voltage) was analyzed. The syncope group had more frequent fQRS (81%) than did the asymptomatic group (21%, P < .01) and the incidence of fQRS was not different before and after removal of predisposing factors. The incidence of organic heart disease was not different between the two groups. No differences in QTc interval were noted between the syncope and asymptomatic groups, although the syncope group had longer QT and Tpe intervals and higher U wave than the asymptomatic group (P < .01). Acquired predisposing factors promoted repolarization abnormality (especially prolongation of QT and Tpe intervals), and the existence of fQRS had an important role in the development of TdP in patients with acquired LQTS.

Serum neuron-specific enolase level as a biomarker in differential diagnosis of seizure and syncope

Patients who experience a single generalized tonic-clonic seizure or syncope may have similar clinical symptoms, which can cause difficulty in the differential diagnosis. The aim of this study was to examine whether serum neuron-specific enolase (NSE) has diagnostic relevance as a biochemical marker for these disorders. Serum NSE levels were analyzed following a loss of consciousness in patients who were diagnosed with a seizure (n = 52) and syncope (n = 42) compared with normal controls (n = 91). NSE was 14.97 ± 7.57 ng/dl for the seizure group, 10.15 ± 3.22 ng/dl for the syncope group, and 10.03 ± 1.28 ng/dl for the control group. The seizure group showed a significantly increased serum NSE (p < 0.05) compared to the syncope and control groups. By receiver operating characteristic (ROC) curve analysis, the cut-off value with the highest diagnostic accuracy was defined as 11.5 ng/ml with a sensitivity of 0.58 and specificity of 0.91. The NSE values of the syncope and control groups showed no significant differences. Syncope may not influence diffuse brain damage. Serum NSE measurement may be a helpful test for the identification and diagnosis of a seizure rather than syncope.

Age-related hemodynamic changes during vasovagal syncope

Objective The aim of our study was to identify specific age-related hemodynamic changes during upright tilt test in patients with vasovagal syncope. Methods We studied 115 subjects who were referred to us for unexplained syncope during 65° tilt with pharmacological challenge (s.l. nitrate) by noninvasive monitoring of blood pressure (Finometer). Two derived variables were also considered: total peripheral resistance and stroke volume. The patients were divided into 3 groups by age: Group 1, 10–30 yrs; Group 2, 31–50 yrs; and Group 3, > 51 yrs. Results The test was positive in 65 patients (57%). During the first 20 min of the test, older patients experienced lower increases in heart rate ( p < 0.00001) and premature reduction of total peripheral resistance ( p < 0.005) and systolic blood pressure ( p < 0.005). Group 1 showed more pronounced decreases in stroke volume ( p < 0.01). No differences emerged between negative and positive patients. In the 5 min that preceded syncope, younger subjects experienced a distinct, transient increase in heart rate immediately before symptom onset ( p < 0.005). Blood pressure was prematurely and progressively decreased in Group 3, whereas it decreased only in the 90 s prior to syncope in Groups 1 and 2 ( p < 0.01). Conclusions Our results suggest that blunted sympathetic activation occurs during passive orthostatism in older patients. On the other hand, hemodynamic changes before symptom onset seem to indicate as in younger subjects syncope results from an excessive sympathovagal reaction, whereas in older subjects it is related to an overwhelming, progressive central vagal activity that is associated with a defective peripheral sympathetic activation.

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.

Increased phase synchronization and decreased cerebral autoregulation during fainting in the young

Vasovagal syncope may be due to a transient cerebral hypoperfusion that accompanies frequency entrainment between arterial pressure (AP) and cerebral blood flow velocity (CBFV). We hypothesized that cerebral autoregulation fails during fainting; a phase synchronization index (PhSI) between AP and CBFV was used as a nonlinear, nonstationary, time-dependent measurement of cerebral autoregulation. Twelve healthy control subjects and twelve subjects with a history of vasovagal syncope underwent 10-min tilt table testing with the continuous measurement of AP, CBFV, heart rate (HR), end-tidal CO2 (ETCO2), and respiratory frequency. Time intervals were defined to compare physiologically equivalent periods in fainters and control subjects. A PhSI value of 0 corresponds to an absence of phase synchronization and efficient cerebral autoregulation, whereas a PhSI value of 1 corresponds to complete phase synchronization and inefficient cerebral autoregulation. During supine baseline conditions, both control and syncope groups demonstrated similar oscillatory changes in phase, with mean PhSI values of 0.58+/-0.04 and 0.54+/-0.02, respectively. Throughout tilt, control subjects demonstrated similar PhSI values compared with supine conditions. Approximately 2 min before fainting, syncopal subjects demonstrated a sharp decrease in PhSI (0.23+/-0.06), representing efficient cerebral autoregulation. Immediately after this period, PhSI increased sharply, suggesting inefficient cerebral autoregulation, and remained elevated at the time of faint (0.92+/-0.02) and during the early recovery period (0.79+/-0.04) immediately after the return to the supine position. Our data demonstrate rapid, biphasic changes in cerebral autoregulation, which are temporally related to vasovagal syncope. Thus, a sudden period of highly efficient cerebral autoregulation precedes the virtual loss of autoregulation, which continued during and after the faint.

Impedance cardiography: a role in vasovagal syncope diagnosis?

vasovagal syncope is the most common cause of syncope in all age groups, with diagnosis usually based on history, examination and basic investigations to exclude alternative causes of syncope. Where doubt exists, the head-up tilt (HUT) test is used for diagnosis but is time consuming and lacks a gold standard to accurately assess sensitivity and specificity. Alternative methods of diagnosing vasovagal syncope would thus be useful. to investigate the potential for impedance cardiography (ICG)-derived haemodynamic measures to predict HUT test outcome in unexplained syncope. prospective controlled study. eighty-six patients with unexplained syncope and 43 non-syncopal controls. all subjects underwent continuous heart rate, blood pressure and ICG measurements during 10 min supine rest and during HUT. Vasovagal syncope was diagnosed when patients experienced symptom reproduction with concomitant haemodynamic derangements. during rest prior to HUT, the syncopal group had higher mean heart rate (P = 0.0008) and lower baroreceptor effectiveness index (P < 0.0001) compared to non-syncopal controls. On comparing patients who presented with unexplained syncope who subsequently had a positive HUT (therefore a diagnosis of vasovagal syncope 55 [64%]; mean age 47 years, range 17-85) to those having a negative tilt test (n = 31; mean age 47 years, range 17-88), there were no significant differences found in cardiovascular or autonomic parameters prior to HUT. A predictive ROC curve model at a 85% threshold allowed using cardiac index (CI), end-diastolic index (EDI) and left ventricular work index (LVWI) would identify those who would have a positive HUT from baseline cardiovascular measurements (CI >3.5, EDI > 77, LVWI >4.7) with 93% sensitivity and 17% specificity. supine haemodynamic measures derived from transthoracic ICG can simply, non-invasively and sensitively differentiate HUT-positive patients from those with negative tilt tests. Further work is needed, particularly in older patients, before this technique can be used in clinical practice.

Sympatho-vagal responses in patients with sleep and typical vasovagal syncope

Sleep syncope is a recently described form of vasovagal syncope that interrupts sleep. The pathophysiology of this condition is uncertain but a 'central' non-baroreflex-mediated trigger has been suggested. In the present study, we tested the hypothesis that patients with sleep syncope have abnormal sympatho-vagal responses to non-baroreflex, but normal responses to baroreflex stimuli. We collected historical data from SS patients (patients with vasovagal syncope with sleep syncope; n=16) and NSS patients (patients with vasovagal syncope without sleep syncope; n=35), including demography, and triggers and symptoms during syncope. MBP (mean blood pressure), HR (heart rate) and MSNA (muscle sympathetic nerve activity) in SS patients were compared with NSS patients and matched controls (n=16) during HG (handgrip), CPTs (cold pressor tests), HUT (head-up tilting) and tilt-induced pre-syncope. Patients and controls were of similar age and gender distribution [SS patients, age 46.0+/-4 years (69% female); NSS patients, 47.3+/-4 years (63% female); controls, 43.7+/-5 years (69% female)]. Compared with NSS patients, SS patients reported more fainting episodes: (i) triggered by phobias (75 compared with 37%; P=0.001); (ii) while in the horizontal position (44 compared with 6%; P=0.001); and (iii) associated with abdominal symptoms (69 compared with 9%; P=0.001). Compared with controls, the MBP response to HG was attenuated in SS patients (P=0.016), and MSNA (burst frequency and incidence) responses to CPT were attenuated in both syncope groups (SS, P=0.011 and 0.003 respectively; NSS, P=0.021 and 0.049 respectively). MSNA responses to HUT did not differ. For both non-baroreflex and baroreflex responses, there were no differences in any of the MSNA indices between the syncope groups. Patients with vasovagal syncope, with or without sleep syncope, have very similar sympatho-vagal responses to both non-baroreflex and baroreflex stimuli. This is consistent with sleep syncope being a subform of vasovagal syncope. Attenuation of sympathetic responses to non-baroreflex pathways may be important in the mechanism of vasovagal syncope.

Assessment of the QT Interval in the Electroencephalography (EEG) of Children With Syncope, Epilepsy, and Attention-Deficit Hyperactivity Disorder (ADHD)

The interpretation of QT interval is often neglected during electroencephalography (EEG) reading. We compared the incidence of prolonged QT interval, as seen in the electrocardiography (ECG) recording lead of the EEG, in children presenting with seizure, syncope, or attention-deficit hyperactivity disorder (ADHD). Abnormal QT was defined as >460 ms. The incidence of prolonged QT in the seizure, syncope, and ADHD groups was 1/50 (2%), 7/50 (14%), and 2/50 (4%), respectively (P = .036, chi-square). The mean +/- SD of QT were 405 +/- 34, 424 +/- 39, and 414 +/- 36, respectively (P = .035, analysis of variance [ANOVA], syncope group, compared with seizure group). The incidence of prolonged QT as measured in the EEG was unexpectedly high in children presenting with seizure, syncope, or ADHD. These data support the concept that QT evaluation should be emphasized during routine EEG reading, as it may aid in identifying cases of undiagnosed cardiac conduction abnormalities. Prospective studies comparing EEG-ECG tracings with 12-lead ECG are warranted.

Diagnosis of unexplained syncope in children: a multi-center study

To examine the diagnostic value of head-up tilt test in children with unexplained syncope (UPS). A total of 379 children (171 males, 208 females) aged 3-18 years, mean age (12 +/- 3) years with unexplained syncope from Beijing, Hunan, Hubei and Shanghai and undergoing baseline head-up tilt tests (BHUTT) or head-up tilt tests potentiated with nitroglycerine (SNHUTT) under a quiet circumstance were selected as the syncope group. Ten healthy children (5 males, 5 females) aged 9-15 years with a mean age of (11.4 +/- 2.1) years, were recruited as the control group. SPSS 10.0 software was used for data analysis. In 379 children with unexplained syncope, 67 (17.7%) were of postural orthostatic tachycardia syndrome (POTS), 157 (41.4%) of vasovagal syncope vasoinhibitory pattern, 14 (3.7%) of vasovagal syncope cardioinhibitory pattern, 47 (12.4%) of vasovagal syncope mixed pattern, 1 (0.3%) of orthostatic hypotension (OH) and 93 children (24.5%) of UPS. In syncope group and control group, the positive rate of BHUTT was 55.9% and 0 respectively and it was 75.5% and 20.0% respectively for SNHUTT. During BHUTT, the mean time of positive response occurrence was (16 +/- 12) minutes, and the posture when positive response appeared was at a tilt angle of 60 degrees. For SNHUTT, the mean time of positive response occurrence was (6 +/- 4) minutes and the posture was at a tilt angle of 60 degrees when potentiated with nitroglycerine. HUTT is an objective diagnostic tool of UPS. With a high diagnostic positive rate, SNHUTT can improve the diagnostic positive rate of BHUTT. Meanwhile the time of positive response occurrence during SNHUTT is markedly shorter than BHUTT.

A Novel Method for the Diagnosis of Neurocardiogenic Syncope: Heart Rate Recovery Index

Objectives: Neurocardiogenic syncope is a common and challenging problem in clinical practice. Heart rate recovery after the first minute of exercise is mainly controlled by the parasympathetic nervous system. The aim of the present study was to evaluate heart rate recovery as an index of parasympathetic tonus for the diagnosis of neurocardiogenic syncope. Methods and Results: Ninety five patients (mean age 36.5 ± 11.8 years), who had vasovagal syncope episodes documented by tilt table testing and 70 healthy subjects (mean age 32.9 ± 9.1 years) were included in this study. Maximal exercise stress testing was performed in both groups and heart rate recovery values were calculated. Heart rate recovery was calculated by subtracting recovery heart rate in the first minute after exercise from peak heart rate. Heart rate recovery was significantly higher in the vasovagal syncope group than the control group during the first minute (42.1 vs. 30.9, p < 0.001). When the cutoff point for heart rate recovery was taken as 35, the sensitivity for the diagnosis of vasovagal syncope was 81% and the specificity was 78%. Conclusion: Results of our study show that heart rate recovery is greater in the first minute after exercise in vasovagal syncope patients and that it has a supportive role in the diagnosis of neurocardiogenic syncope.

Orthostatic Hypotension As Cause of Syncope in Patients Older Than 65 Years Admitted to Emergency Departments for Transient Loss of Consciousness

Syncope due to orthostatic hypotension (OH) refers to loss of consciousness caused by hypotension induced by the upright position; it is an important risk factor for fall-related physical injuries, especially in the elderly adults. We evaluated the prevalence of OH syncope and the clinical characteristics of patients older than 65 years with syncope due to OH in the Evaluation of Guidelines in Syncope Study 2 group population. Two hundred fifty nine patients older than 65 years consecutively admitted to the emergency department because of loss of consciousness in a period of a month were submitted to a standardized protocol approved by the European Task Force for the diagnosis of syncope; all the patients were studied by a trained physician who interacted with a central supervisor as the management of syncope was concerned, using a decision-making software. Prevalence of OH syncope was 12.4%. Patients with OH syncope were more likely to be affected by Parkinson's disease and by other neurological diseases. ST changes and longer values of QTc were found in OH syncope group, and they took a greater number of diuretics, nitrates, and digoxin. In multivariate analysis, Parkinson's disease (p = .001) and use of nitrates (p = .001) and diuretics (p = .020) were independently related to OH syncope. In patients older than 65 years, Parkinson's disease and neurological comorbidity are strictly related to OH syncope. Moreover, this study suggests the independent link between OH syncope and the use of vasoactive drugs, identifying the majority of cases as adverse drug reaction, a preventable risk factor for syncope and falls in the older population.

Seizure or syncope: the diagnostic value of serum creatine kinase and myoglobin levels

To determine if the serum levels of creatine kinase and myoglobin can be used to differentiate the grandmal tonic-clonic seizure and syncope activities in the emergency department (ED). Consecutive patients over 16 years old who presented to an ED of a tertiary care hospital with a witnessed tonic-clonic seizure activity and a history of a transient loss of consciousness with normal neurological exams in the ED were selected to either seizure or syncope groups. Patients with an unclear history of seizure or syncope with more than 4 h of the activity and with any conditions that could elevate creatine kinase and myoglobin levels were excluded. Serum samples were drawn at presentation and at the fourth hour of the event. Thirty-seven syncope and 26 generalized tonic-clonic seizure patients with a definite history were assigned to study groups. There was not a statistically significant difference in the time of drawing of the first serum sample among groups. No statistically significant differences were determined with the first samples of creatine kinase and myoglobin for both groups. Serum levels of creatine kinase drawn at the fourth hour of the activity were significantly higher in favor of the seizure group. However, myoglobin levels were insignificant at the fourth hour. Serum creatine kinase measured at the fourth hour of loss of consciousness may be a potentially useful laboratory test to differentiate tonic-clonic seizure from syncope. Patently, it requires and warrants further study.

Polymorphism C1114G of Gene Encoding the Cardiac Regulator of G-Protein Signaling 2 May Be Associated with Number of Episodes of Neurally Mediated Syncope

The cardiac regulator of G-protein signaling 2 (RGS2) negatively regulates G-protein-coupled receptor signaling. The C1114G polymorphism reduces RGS2 gene expression. This molecular disorder may be one of the important factors influencing progress of neurally mediated syncope. The aim of the study was to evaluate the association between C1114G RGS2 polymorphism and tilting results and number of syncope episodes in patients with no other diseases. Of 214 tilted patients (39% males, 39.7 +/- 17.1 years of age), genomic DNA was extracted from cellular blood components. C1114G RGS2 polymorphism was diagnosed by designed primers. Clinical variables and genetic traits were introduced into multivariate stepwise regression. Analysis was performed as follows: positive tilting n = 145 vs. negative n = 69, positive passive n = 49 vs. nitroglycerin (NTG)-positive n = 96, dominant vasodepressive n = 111 vs. cardioinhibition n = 34; and in number of syncope groups with cut-off >or=10 vs. <10. No relationship was found between the studied polymorphism and outcome of tilting (p >0.05). In multivariate regression model, homozygosity G/G 1114 RGS2 was the only variable associated with a reduced number of episodes of syncope (95% CI 2.3-10.9; p = 0.04). Our preliminary results suggest the association of G/G 1114 RGS2 genotype with the number of episodes of neurally mediated syncope. Detailed molecular mechanism of the influence of the studied polymorphism on syncopal number is probably associated with the reduced expression of RGS2 gene.

Are the results of electrophysiological study different in patients with a pre-excitation syndrome, with and without syncope?

Syncope in Wolff-Parkinson-White (WPW) syndrome may reveal an arrhythmic event or is not WPW syndrome related. The aim of the study is to evaluate the results of electrophysiological study in WPW syndrome according to the presence or not of syncope and the possible causes of syncope. Among 518 consecutive patients with diagnosis of WPW syndrome, 71 patients, mean age 34.5 +/- 17, presented syncope. Transoesophageal electrophysiological study in control state and after isoproterenol infusion was performed in the out-patient clinic. Atrioventricular re-entrant tachycardia (AVRT) was more frequently induced than in asymptomatic patients (n = 38, 53.5%, P < 0.01), less frequently than in those with tachycardia; atrial fibrillation (AF) and/or antidromic tachycardia (ATD) was induced in 28 patients (39%) more frequently (P < 0.05) than in asymptomatic patients or those with tachycardia. The incidence of high-risk form [rapid conduction over accessory pathway (AP) and AF or ATD induction] was higher in syncope group (n = 18, 25%, P < 0.001) than in asymptomatic subjects (8%) or those with tachycardias (7.5%). Maximal rate conducted over AP was similar in patients with and without syncope, and higher in patients with spontaneous AF, but without syncope. Results were not age-related. Tachycardia inducibility was higher in patients with syncope than in the asymptomatic group. The incidence of malignant WPW syndrome was higher in patients with syncope than in asymptomatic or symptomatic population, but the maximal rate conducted over AP was not higher and another mechanism could be also implicated in the mechanism of syncope.

The characteristics of neurocardiogenic syncope in children

Purpose : Syncope is relatively common in children and adolescents. Among the etiologies of syncope, neurocardiogenical syncope is the most common, but it is often confounded with seizure. We investigated the clinical features of patients under the age of 15 with neurocardiogenical syncope, compared to patients with neurologic disorders including epilepsy. Methods : Among the children who visited the Department of Pediatrics at Cheongju St. Mary's Hospital and Chungbuk National University Hospital from March 2005 to February 2007, we retrospectively analyzed 69 patients whose chief complaint was syncope. We classified the patients by syncope etiology and made comparisons between the neurocardiogenical syncope (NCS) group and the neurological disorders (ND) group regarding to age; location; time and season in which syncope occurred; associated symptoms, including seizures, provocation factors; prodromes; duration of syncope; frequency of previous syncope; birth history; associated disease; past medical history; family history; neurological exam; physical exam; laboratory findings; electrocardiography; electroencephalography (EEG); head-up tilt test; brain CT; and MRI. Results : Among 69 syncope patients, 53 (76.8%) were in the NCS group and 11 (15.9%) were in the ND group. There were no statistically significant differences between the two study groups except for the presence of prodromes and EEG abnormalities. The presence of prodromes in the NCS group was more common than in the ND group [46.9% (23/49) vs. 9.1% (1/11), (P=0.038)]. The EEG abnormality in the ND group was more common than in the NCS group [90% (9/10) vs. 5.8% (3/52), (P

Clinical Characteristics and Risk Stratification in Symptomatic and Asymptomatic Patients with Brugada Syndrome: Multicenter Study in Japan

Neither the clinical characteristics nor risk stratification in Brugada syndrome have been clearly determined. We compared the clinical and ECG characteristics of symptomatic and asymptomatic patients with Brugada syndrome to identify new markers for high-risk patients. A total of 188 consecutive individuals with Brugada syndrome (mean age 53 +/- 14 years, 178 males) were enrolled in the Japan Idiopathic Ventricular Fibrillation Study (J-IVFS). Clinical and ECG characteristics were evaluated in three groups of patients: Ventricular fibrillation (VF) group: patients with documented VF (N = 33); Syncope (Sy) group: patients with syncope without documented VF (N = 57); and asymptomatic (As) group: subjects without symptoms (N = 98). Their prognostic parameters were evaluated over a 3-year follow-up period. (1) Clinical characteristics: incidence of past history of atrial fibrillation (AF) was significantly higher in the VF and Sy groups than in the AS group (P = 0.04). (2) On 12-lead ECG, r-J interval in lead V2 and QRS duration in lead V6 were longest in the VF group (P = 0.001, 0.002, respectively). (3) Clinical follow-up: during a mean follow-up period of 37 +/- 16 months, incidences of cardiac events (sudden death and/or VF) were higher in the symptomatic (VF/Sy) groups than in the As group (P < 0.0001). The r-J interval in lead V2 >/= 90 ms and QRS duration in lead V6 >/= 90 ms were found to be possible predictors of recurrence of cardiac events in symptomatic patients. Prolonged QRS duration in precordial leads was prominent in symptomatic patients. This ECG marker may be useful for distinguishing high- from low-risk patients with Brugada syndrome.