Psychiatric conditions in patients with recurrent unexplained syncope.

AIMS: The relationship between syncope and psychiatric disorders is little investigated. This study evaluated the prevalence of psychiatric diseases and prognostic outcome in patients with recurrent unexplained syncope. METHODS AND RESULTS: After an inconclusive standard diagnostic work-up for syncope, including head-up tilt testing, a psychiatric evaluation was offered to 50 consecutive patients with recurrent syncope. The evaluation was accepted by 26 patients (77% females, 36 +/- 16 years) and refused by 24 (63% females, 50 +/- 19 years). A psychiatric disorder was diagnosed in 21 (81%) patients: 12 had depression, four panic attacks, two general anxiety, and three a somatization disorder. Only five patients showed normal psychosocial function. Of the patients with psychiatric disorders four accepted psychiatric care, such as psychotherapy and/or pharmacotherapy; 17 patients refused treatment. During 6 months of follow-up no patient under psychiatric care had syncope, while all patients without psycho- or pharmacotherapy had recurrent syncopal events. In these patients the median of syncopal episodes was three in a 6 months interval before and after clinical assessment. Patients who refused both psychiatric evaluation and therapy continued to experience syncope as before. CONCLUSIONS: In patients with recurrent unexplained syncope psychiatric alteration is common. However, patients seldom accepted a psychiatric evaluation and treatment.     

Carotid sinus syndrome--clinical characteristics in elderly patients.

Carotid sinus massage was carried out on 130 consecutive patients referred for investigation of dizziness, syncope or unexplained falls. Carotid sinus syndrome was diagnosed in 33 for whom no other cause of symptoms was identified. Right-sided hypersensitivity was more frequent than left-sided. Thirty per cent identified a prodrome before syncope and 30% had retrograde amnesia for the event. In 52%, symptoms were precipitated by head movement and in 48% by vagal stimuli. Seven described 'drop attacks' but symptoms were reproduced with carotid sinus massage during head-up tilt. Injuries, including fractured neck of femur, were sustained by the majority. Carotid sinus massage should be performed routinely on all elderly patients who have symptoms of unexplained dizziness, falls or syncope. Cardiac pacing relieves syncopal symptoms in those with a predominant cardio-inhibitory response and recurrent syncope.     

Psychiatric profile, quality of life and risk of syncopal recurrence in patients with tilt-induced vasovagal syncope.

AIM: The aim of this study was to investigate the prevalence of psychiatric disorders and quality of life (QoL) in patients with tilt-induced vasovagal syncope and no other comorbidities, and their relationship with the syncopal burden and the risk of recurrence. METHODS: We studied 61 patients with recurrent syncope and positive tilt testing. Controls consisted of 61 sex- and age-matched healthy subjects. Psychiatric diagnoses were formulated on the basis of a structured interview and the Minnesota Multiphase Personality Inventory-2 questionnaire. QoL was assessed by means of the Short-Form Health Survey questionnaire. Patients were followed up for at least 1 year. RESULTS: The presence of psychiatric disorders was higher among patients than controls (71% vs. 23%, P < 0.001), with a prevalence of anxiety (28% vs. 5%), mood (18% vs. 3%), and somatization disorders (29% vs. 3%). The scores of all the QoL scales were statistically lower in patients than controls. An inverse correlation was found between QoL scale scores and syncopal burden. The presence of psychiatric disorders was predictive of syncopal recurrence during follow-up. CONCLUSION: Psychiatric disorders are common in patients with tilt-induced vasovagal syncope, and seem to predict the risk of recurrence. QoL is impaired in these patients, and is inversely correlated with the syncopal burden.     

Exercise-related syncope in young competitive athletes without evidence of structural heart disease. Clinical presentation and long-term outcome.

AIMS: Exercise-related syncopal spells in athletes receive great attention and are a source of anxiety in the sporting world. The aim of the present study is to describe the clinical presentation, the yield of the initial diagnostic work-up and the long-term outcome of a series of consecutive competitive athletes with recurrent exercise-related syncopal spells. METHODS AND RESULTS: The study cohort included 33 athletes (20 females, mean age 21.4+/-3.2 years) referred for recurrent unexplained episodes of exercise-related syncope (mean number of spells before evaluation 4.66+/-1.97). All athletes underwent an extensive evaluation, including echocardiography, 24-h electrocardiographic monitoring, exercise testing, cardiac electrophysiological study and head-up tilt testing. The echocardiographic examination revealed the presence of a mitral valve prolapse in two cases (6.0%). During maximal exercise testing, four athletes (12.1%) developed hypotension associated with pre-syncope. Twenty-two subjects (66.6%) showed a positive response to head-up tilt testing. During follow-up (33.5+/-17.2 months) 11/33 athletes (33.3%) showed at least one recurrence of exercise-related syncope (mean time to first recurrence 20.4+/-14.5 months). No other adverse event of any kind was noted during follow-up. The Kaplan-Meier estimates of first recurrence of exercise-related syncope after 12, 36 and 60 months were 9.1%, 24.4% and 42.9%. The number and frequency of exercise-related syncopal spells before evaluation were found to be univariate predictors of syncope recurrence (P<0.001). However, in the multivariate analysis, the number of exercise-related syncopal spells before evaluation was found to be the only independent predictor of syncope recurrence (P<0.05). CONCLUSIONS: These findings support the idea that recurrent exercise related-syncope is not associated with an adverse outcome in athletes without cardiac disease.     

Neurocardiogenic mechanisms of unexplained syncope in idiopathic dilated cardiomyopathy

Syncope in patients with advanced heart failure is a sign of poor prognosis. The cause of syncope in patients with dilated cardiomyopathy (DC) is not fully recognized and may remain elusive even after standardized evaluation. The purpose of the present study was to examine the implication of neurally mediated mechanisms in the pathophysiology of syncopal episodes in patients with DC. Twenty-six patients (21 men, 5 women; mean age 59 +/- 2 years, range 38 to 79) with DC and left ventricular ejection fractions 相似文献   

Unexplained syncope evaluated by electrophysiologic studies and head-up tilt testing

OBJECTIVE: To determine the clinical characteristics of subgroups of patients with unexplained syncope having electrophysiologic studies and head-up tilt testing and to assess the efficacy of various therapies. DESIGN: Retrospective study. SETTING: Inpatient services of a tertiary referral center. PATIENTS: Eighty-six consecutively referred patients with unexplained syncope. MEASUREMENTS: All patients had electrophysiologic examinations. Patients with negative results subsequently had head-up tilt testing. MAIN RESULTS: Twenty-nine (34%) patients (group 1) had abnormal electrophysiologic results, with sustained monomorphic ventricular tachycardia induced in 72%. Thirty-four (40%) patients (group 2) had syncope provoked by head-up tilt testing. The cause of syncope remained unexplained in 23 (26%) patients (group 3). Structural heart disease was present in 76%, 6%, and 30% of groups 1, 2, and 3, respectively. In group 1, pharmacologic or nonpharmacologic therapy was recommended based on electrophysiologic evaluation. All group 2 patients had negative results on head-up tilt testing while receiving oral beta blockers (27 patients) or disopyramide (7 patients). Group 3 patients did not receive any specific therapy. During a median follow-up period of 18.5 months, syncope recurred in 9 (10%) patients. CONCLUSIONS: The combination of electrophysiologic evaluation and head-up tilt testing can identify the underlying cause of syncope in as many as 74% of patients presenting with unexplained syncope. Therapeutic strategies formulated according to the results of these diagnostic tests appear to prevent syncope effectively in most patients.     

Syncope and seizures of psychogenic origin: identification with head-upright tilt table testing

Psychogenic seizures and psychogenic syncope are common disorders but are difficult to identify. Head-upright tilt table testing has emerged as a promising means of evaluating vasovagally mediated syncope and convulsive syncope. Of a total of 42 patients evaluated by head-up tilt for recurrent syncope and 10 evaluated for recurrent idiopathic seizures, a total of 5 patients experienced syncope and 3 had tonic-clonic seizure activity unaccompanied by any significant changes in blood pressure, heart rate, transcranial Doppler cerebral blood flow velocity, and electroencephalographic monitoring. Psychiatric evaluation revealed that seven patients suffered from conversion reactions and one from probable malingering. We conclude that patients who pass out or convulse during head-upright tilt without any change in physiologic parameters can be presumed psychogenic in origin and may be referred for psychiatric evaluation without further expensive diagnostic studies.     

Evaluation of beta-adrenergic blockader therapy in vasovagal syncope reproduced by head-up tilt test]

Increased sympathetic tone is one physiopathological mechanism of vasovagal syncope. In this case, betablocker therapy is logical. The reports in the literature suggest that the head-up tilt test can reliably reproduce vasovagal syncope. Ten patients (4 men and 6 women, mean age 59 +/- 18 years) who suffered from recurrent vasovagal syncopes (2 to 10 attacks in 6 patients and more than 10 in the other 4) with a positive initial head-up tilt test (syncope or severe dizziness with marked hypotension after a maximum of 40 minutes at 60 degrees) were treated with atenolol (200 mg daily in 7 cases and 100 mg daily in the other 3). A second head-up tilt test was performed 15 +/- 6 days later under betablocker therapy; this test was negative in 7 and remained positive in 3 cases. Irrespective of the result, the 10 patients followed the same therapy at the same dosage. After 9 +/- 5 months, 3 patients had another syncopal attack; 2 stopped taking their medication and the third patient continued the betablocker because there was a marked reduction in the frequency of his attacks. There were no further syncopal episodes during follow-up of the other 7 patients. The medium-term efficacy could not be predicted from the results of the second head-up tilt test. The following conclusions may be drawn from this study: The head-up tilt test becomes negative in 70% of cases after introducing betablocker therapy, assuming a 100% reproductivity. This treatment is effective in over half the patients at medium term and should be considered in patients with recurrent vasovagal syncope.     

Usefulness of head-up tilt test in evaluating patients with syncope of unknown origin and negative electrophysiologic study

The vasovagal nature of syncope, which remained unexplained despite full clinical and electrophysiologic investigation, was evaluated by means of 60 degrees head-up tilt test for 60 minutes. Thirty patients (17 men and 13 women, mean age 65 years, 19 with and 11 without organic heart disease) with 1 to 28 (mean 5) episodes of syncope of unknown origin were studied. Head-up tilt test was considered positive if syncope developed in association with hypotension, bradycardia, or both. During baseline head-up tilt 15 patients (50%) had a positive response. Ten patients had a vasodepressor response (marked hypotension without marked bradycardia) and 5 had a mixed response (marked hypotension with marked bradycardia). None of 8 control subjects became symptomatic during the test. Baseline head-up tilt test was positively reproducible in 10 of 14 patients (71%). Nine of these 10 patients underwent serial head-up tilt tests after drug administration to determine the pathogenesis of vasovagal syncope. Atropine prevented tilt-induced syncope in 3 of 8 patients (37.5%), propranolol in 2 of 8 (25%) and etilephrine in 7 of 7 (100%). Seven patients received long-term drug treatment with drugs selected on the basis of acute drug testing. One responder to atropine received transdermal scopolamine and 6 received etilephrine. None of these 7 patients had syncopal recurrences or death during a mean follow-up of 12 months. Head-up tilt is a very sensitive and highly specific test to unmask susceptibility to vasovagal reaction in patients with syncope of unknown origin. Withdrawal of alpha-sympathetic stimulation is a principal mechanism responsible for vasodilation and syncope during head-up tilt.(ABSTRACT TRUNCATED AT 250 WORDS)     

Long-term follow-up of children and adolescents with syncope; predictor of syncope recurrence.

BACKGROUND: Previous studies have shown that investigation by tilt testing is very appropriate in paediatrics, but the characteristics of children and adolescents who are at high risk of recurrent syncope, once the diagnosis is established, remain unclear. This study was set up to analyse the risk factors attributed to syncope recurrence in paediatric patients. METHODS: One hundred and one children and adolescents aged 7 to 18 years, undergoing a tilt test for recurrent syncope, were studied. They were subsequently followed-up in clinic visits with a final interview at the clinic or by telephone at the end of the follow-up period. RESULTS: A head-up tilt test elicited syncope or pre-syncope in 67 children. The positive responses included vasovagal syncope in 58 patients and psychogenic syncope in nine patients. Gender, age, number of pre-tilt test syncopal episodes or duration of symptoms made no difference to children with positive or negative tilt test results. Following the tilt test, 43 of 67 children with a positive tilt test were treated empirically. No treatment was prescribed for the remaining 24 with a positive test, or for those with a negative tilt test. There were no differences between treated and untreated children with respect to the number of pre-tilt test syncopes, duration of symptoms and duration of follow-up. Follow-up data were available in 97 children. During a mean follow-up of 46+/-28 months, syncope recurred in 31 children (32%). The recurrence rate was similar between positive and negative tilt test groups (22/66 vs 9/31, respectively; P=ns), as well as between treated and untreated children (14/43 vs 8/23, respectively; P=ns). When comparing syncope-free children at follow-up in a univariate analysis, children with recurrent syncope reported a greater number of historical syncopal spells (7+/-8 vs 3+/-3, P=0.01). In addition linear correlation (r=0.6, 95% CI 0.47 to 0.72, P<0.0001) was significant between the number of historical syncope episodes and the risk of recurrent syncope. CONCLUSIONS: These findings suggest that the risk of syncope recurrence for children and adolescents with such a history is not correlated to the tilt test result or prophylactic treatment. The number of historical syncopal spells is, however, predictive.     

A randomized, double-blind, placebo-controlled study of permanent cardiac pacing for the treatment of recurrent tilt-induced vasovagal syncope. The vasovagal syncope and pacing trial (SYNPACE).

AIMS: Recently, some studies revealed the efficacy of pacemaker implantation in decreasing recurrences in patients with vasovagal syncope. As these studies were not blinded or placebo-controlled, the benefits observed might have been due to a bias in the assessment of outcomes or to a placebo effect of the pacemaker. We performed a randomized, double-blind, placebo-controlled study in order to ascertain if pacing therapy reduces the risk of syncope relapse. METHODS AND RESULTS: Twenty-nine patients (53 +/- 16 years; 19 women) with severe recurrent tilt-induced vasovagal syncope (median 12 syncopes in the lifetime) and 1 syncopal relapse after head-up tilt testing underwent implantation of a pacemaker, and were randomized to pacemaker ON or to pacemaker OFF. During a median of 715 days of follow-up, 8 (50%) patients randomized to pacemaker ON had recurrence of syncope compared to 5 (38%) of patients randomized to pacemaker OFF (p = n.s.); the median time to first syncope was longer in the pacemaker ON than in pacemaker OFF group, although not significantly so (97 [38-144] vs 20 [4-302] days; p = 0.38). There was also no significant difference in the subgroups of patients who had had a mixed response and in those who had had an asystolic response during head-up tilt testing. CONCLUSION: Our data were unable to show a superiority of active pacing versus inactive pacing in preventing syncopal recurrence in patients with severe recurrent tilt-induced vasovagal syncope.     

A randomised prospective comparison of three protocols for head-up tilt testing and carotid sinus massage

INTRODUCTION: Head-up tilt testing is an important tool in the diagnosis of syncope. Several different protocols are in use. This study aimed to compare three different protocols in an unselected population of patients with recurrent unexplained syncope and to assess long-term outcome using conventional tilt-directed management or implantable loop recorder (Reveal Plus)-directed management, allowing evaluation of the sensitivity and specificity of the technique. METHODS: Patients with recurrent unexplained syncope were randomized to one of three tilt protocols: Drug-free--70 degree tilt, 45 min, CSM at 5 and 45 min. GTN--70 degree tilt, 35 min, CSM at 5 min, 400 microg of glyceryl trinitrate spray administered sublingually at 20 min. Adenosine--70 degree tilt, 5 min, CSM when blood pressure is stable in upright position, adenosine bonus at 150 microg/kg after CSM.Tilts were terminated at the onset of syncope, when systolic BP reached 60 mm Hg, or in the presence of prolonged hypotension (> 3 min systolic BP < 80 mm Hg). Appropriate therapies were commenced according to the result of the tilt test. All patients without a definite indication for immediate cardiac pacing (asystolic tilt) were randomized to conventional management or ILR implantation. Recurrent syncopal events were compared to tilt outcome, allowing estimation of sensitivity and specificity. RESULTS: Of 214 patients, aged 68+/-18 years, 55% were female, with a median of three previous syncopes. 13 patients received pacemakers due to asystolic syncope during tilt testing. The proportion of VASIS classification diagnoses was similar with each protocol; however more positive diagnoses resulted from the GTN protocol (p=0.0013). 47% of patients achieved a diagnosis with tilt testing. We were able to correlate a subsequent spontaneous syncope to tilt result in 36 patients (18%). Heart rate during a spontaneous event was similar to that obtained during tilt testing (+/- 10%) in 55% of cases. Sensitivities for combined protocols, adenosine, GTN, and drug-free protocols were 50%, 50%, 100%, and 21%, respectively. Specificities were 85%, 100%, 75%, and 71%, respectively. CONCLUSIONS: A high diagnosis rate for unexplained syncope can be achieved with tilt testing. The GTN protocol resulted in significantly more diagnoses than the other compared protocols with good sensitivity and adequate specificity. Sensitivity of the drug-free tilt test was lower than drug-augmented tilt testing.     

Value and limits of the tilt-test in the etiological diagnosis of transient malaise]

This study was undertaken to assess the usefulness of the head-up tilt test in the diagnosis of vasovagal syncope and to evaluate the indications of this investigation. The test consists in a 30 minute period in the horizontal decubitus position followed by a 60 degrees head-up tilt position for 30 minutes. In the 26 subjects in whom the diagnosis of repeated vasovagal syncope had been made on the basis of typical prodromic symptoms after exclusion of all other causes, the test induced a vasodepressive or vagal reaction in 10 cases (38%) 20 +/- 4 minutes after tilting. In 8 patients in whom the test was performed within 48 hours of their syncopal episode, a similar malaise was induced in 7 cases. Twenty patients with repeated malaise without loss of consciousness had no symptoms during the test which was also negative in 10 normal control subjects. In a group of 27 subjects with unexplained syncope after clinical and paraclinical investigations, the test was accompanied by a malaise on five occasions (19%). Using this protocol, the tilt test had good specificity but moderate sensitivity in the diagnosis of vasovagal syncope. Its sensitivity increased when performed within 48 hours of syncope. It is of no value in the diagnosis of recurrent malaise without loss of consciousness.     

Upright postures and isoproterenol infusion for provocation of neurocardiogenic syncope: A comparison of standing and head-up tilting

Head-up tilt testing has proved to be useful in provocation of neurocardiogenic syncope. The purpose of this study was to examine whether simply assuming an upright posture by standing can be an alternative to the head-up tilt testing for diagnosis of neurocardiogenic syncope. Eight-four patients with recurrent unexplained syncope and 22 normal volunteers were recruited into the study. Forty-seven patients with syncope and all normal volunteers received the standing test. Thirty-seven of the patients with syncope received head-up tilt testing (90 degrees). All subjects lay down for 5 minutes and then assumed an upright posture until syncope or presyncope occurred or until a maximum of 10 minutes was reached in each stage of the test. The tests included four stages: baseline and infusion of 1, 2, or 3 μg/min isoproterenol in each of the successive stages. Five subjects could not tolerate the procedure, and further testing was terminated. Overall, the standing test was positive in 83% of the patients with syncope, and its specificity was 74%. The head-up tilt testing was positive in 75% of the patients with syncope. The duration of assuming an upright posture before occurrence of syncope or presyncope was significantly longer in the syncope-tilting group in the third stage (p < 0.01) and the fourth stage (p < 0.05) compared with the syncope-standing group. However, the curves of the time course for cumulative positive rates were not significantly different (p = 0.0739) in the two groups. The standing test can serve as an alternative to head-up tilt testing and can be applied to patients with recurrent unexplained syncope for confirmation of the diagnosis.     

Comparison of provocative tests for unexplained syncope: isoprenaline and glyceryl trinitrate for diagnosing vasovagal syncope.

AIMS: To compare the sensitivity, specificity and adverse event profile of glyceryl trinitrate head-up tilt with isoprenaline head-up tilt in the diagnosis of vasovagal syncope in patients with unexplained syncope and healthy controls. METHODS AND RESULTS: Forty-eight patients with unexplained syncope and negative passive head-up tilt at 70 degrees for 40 min, and 14 healthy controls underwent glyceryl trinitrate head-up tilt and isoprenaline head-up tilt (maximum dose 5 microg x min(-1)) one week apart in random order. Outcome measures were production of symptoms (syncope, pre-syncope) with development of hypotension. In those with negative passive head-up tilt, the sensitivity of glyceryl trinitrate for diagnosing vasovagal syncope was 48% and the specificity was 71%. Glyceryl trinitrate was well tolerated. Isoprenaline sensitivity was 21% with specificity 64%. Side-effects prevented completion of the test in 68%. Commonest adverse events were the development of hypertension or tachycardia and intolerable flushing or nausea. CONCLUSIONS: Glyceryl trinitrate head-up tilt is as effective as isoprenaline head-up tilt as a provocative agent for vasovagal syncope and has a lower incidence of adverse events.     

直立训练对血管迷走性晕厥患者疗效的影响因素

目的探讨直立训练对血管迷走性晕厥疗效的影响因素。方法对46例直立倾斜试验阳性的血管迷走性晕厥患者进行至少4周的直立训练,根据随访结果,将其分为复发组和未复发组,对相关临床资料进行统计学分析。结果经1年随访,34例(74%)患者无晕厥复发,12例(26%)患者复发晕厥或晕厥先兆,复发组年龄较高(51±17岁vs32±11岁,P<0.05),治疗前晕厥发作的次数较少[1(1～2)次vs3(1～4)次,P<0.05]。结论年龄和晕厥发作的频率是影响直立训练疗效的因素,年轻和发作频繁的晕厥患者进行直立训练获益更大。     

Effect of time elapsed from spontaneous syncope on the diagnostic performance of the head-up tilt table test

OBJECTIVES: The propensity for spontaneous and tilt-induced neurocardiogenic syncope may exhibit temporal variations. Therefore the diagnostic performance of the head-up tilt test could be improved if it were performed soon after the occurrence of spontaneous syncope. The objective of this study was to assess whether the time interval between the last syncopal episode and tilt table testing influenced the outcome of the test. PATIENTS AND METHOD: Three hundred and fifteen patients undergoing diagnostic tilt table testing potentiated with nitroglycerin for suspected neurocardiogenic syncope were included in the study. The time between the last spontaneous syncope and the tilt table test was recorded and its relationship with the results of the test was analyzed. RESULTS: The tilt table test was positive in 211 patients (67.0%). The time from syncope to test was similar for patients with positive and negative tilt table test results: 28 (1-500) vs 32 (2-700) days (NS). No significant relation was observed between the results of the test and the occurrence of spontaneous syncope during the week, the month or the three months previous to the procedure. However, in men and in patients older than 50 years a higher rate of positive tests was observed if the tilt test was performed within the first month after the last spontaneous syncope. CONCLUSIONS: The time from the last previous spontaneous syncope to the head-up tilt test does not have a significant impact on test outcome in the overall population with suspected neurocardiogenic syncope. However, the rate of positivity might decrease in men and patients older than 50 years if the test is performed later than one month after the spontaneous syncopal episode.     

Syncope of undetermined nature after electrophysiologic study. Usefulness of the head-up tilt test in the diagnosis of vaso-vagal origin and in the choice of treatment

The vaso-vagal nature of syncopes which remained unexplained despite full clinical and electrophysiological investigation was evaluated by means of 60 degrees head-up tilt test for 60 minutes. Thirty patients (16 men and 14 women, mean age 63.6 years, 19 with and 11 without organic heart disease) with 1 to 28 (mean 5.1) episodes of syncope of unknown origin were studied together with 11 asymptomatic control subjects. Head-up tilt test was considered positive if syncope developed in association with hypotension and/or bradycardia. During baseline head-up tilt 15 patients (50%) showed a positive test, with vasodepressor response (marked hypotension without marked bradycardia) in 10 cases and with mixed response (marked hypotension with marked bradycardia) in 5 cases. None of the control subjects became symptomatic during the test. Mean time to syncope was 24.9 minutes. Baseline head-up tilt test was reproducibly positive in 10 out of 14 patients (71%). Eight of these 10 patients underwent serial head-up tilt tests after atropine (0.04 mg/Kg i.v. in 1 minute), propranolol (0.2 mg/Kg i.v. in 3 minutes) and etilefrin (15-30 mg/day orally for 2-3 days) to determine the pathogenesis of vaso-vagal syncope. Atropine prevented tilt-induced syncope in 3 out of 7 patients (43%), propranolol in 2 out of 7 (29%) and etilephrine in 6 out of 6 (100%). Seven patients were chronically treated with drugs selected on the basis of acute drug testing. One patient-responder to atropine received transdermal scopolamine and the other 6 received etilephrine. None of these 7 patients had syncopal recurrences or death during a mean follow-up of 7.7 months, except 1 who experienced another episode of syncope after having discontinued etilephrine 4 months before. These results suggest that: 1) head-up tilt is a very sensitive and highly specific test to unmask susceptibility to vaso-vagal reaction in patients with syncope of unknown origin; 2) withdrawal of alpha-sympathetic stimulation is the principal mechanism responsible for vasodilation and syncope during head-up tilt; 3) alpha-sympathomimetic agents, such as etilephrine, are effective in preventing spontaneous episodes of vaso-vagal syncope during a short-term follow-up.     

Head-up tilt table evaluation in a trained athlete with recurrent vaso-vagal syncope

A 27-year-old trained athlete with recurrent syncope of suspected vaso-vagal origin was evaluated. A 60 degrees head-up tilt table test reproducibly triggered the patient's spontaneous symptoms and allowed the investigation of different modalities of therapy (medical and pacing) in preventing syncopal episodes. The head-up tilt table test may be a useful tool in the evaluation of syncope of vaso-vagal origin, helping to determine the initial precipitating vagal event and the effect of therapy.     

The incidence of malignant vasovagal syndrome in patients with recurrent syncope

We reviewed 322 patients with recurrent syncope between 1984 and 1988. Investigation included limited intracardiac electrophysiological study in all cases with programmed extra-stimulus studies in 48 cases. In 93 patients (29%), all investigations were normal, (including negative extrastimulus in 30). In the other 229 cases syncope was explained by AV-block (n = 111, 34%), sinus node disease (n = 68, 21%), carotid sinus syndrome (n = 32, 10%) and inducible sustained tachyarrhythmia (n = 18, 6%). Prolonged 60 degrees head-up tilt was performed in 71 out of 93 patients with unexplained syncope, and reproduced vasovagal syncope and presenting symptoms in 53 (75%), or 16% of the whole population reported. These patients were diagnosed as having malignant vasovagal syndrome. Positive tilts were significantly less common in a group of 27 subjects of similar age without a history of syncope (7%), and a random sample of 37 patients with atrioventricular block (n = 16), sick sinus syndrome (n = 18) and inducible tachyarrhythmia (n = 3), (19%, 11% and 0% respectively, P less than 0.01). From this retrospective review it appears, therefore, that tilt testing is a valuable provocative tool for vasovagal syncope and may reduce the number of syncopal patients that remain undiagnosed, although these early observations do not allow an exact appraisal of the sensitivity and specificity of the tilt test.