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At least 19 recordsLinked to original sources
PubMed2001

Mechanism of syncope in patients with isolated syncope and in patients with tilt-positive syncope.

BACKGROUND: Because of its episodic behavior, the correlation of spontaneous syncope with an abnormal finding can be considered a reference standard. METHODS AND RESULTS: We inserted an implantable loop recorder in 111 patients with syncope, absence of significant structural heart disease, and a normal ECG; tilt-testing was negative in 82 (isolated syncope) and positive in 29 (tilt-positive). The patients had had >/=3 episodes of syncope in the previous 2 years and were followed up for 3 to 15 months. Results were similar in the isolated syncope group and the tilt-positive group: syncope recurred in 28 (34%) and 10 patients (34%), respectively, and electrocardiographic correlation was found in 24 (23%) and 8 (28%) patients, respectively. The most frequent finding, which was recorded in 46% and 62% of patients, respectively, was one or more prolonged asystolic pauses, mainly due to sinus arrest, preceded for a few minutes by progressive bradycardia or progressive tachycardia-bradycardia. Bradycardia without pauses was observed in 8% and 12% of cases, respectively. The remaining patients had normal sinus rhythm or sinus tachycardia, except for one, who had ectopic atrial tachycardia. In the tilt-positive group, an asystolic syncope was also recorded when the type of response to tilt-testing was vasodepressor or mixed. Presyncopal episodes were never characterized by asystolic pauses; normal sinus rhythm was the most frequent finding. CONCLUSIONS: Homogeneous findings were observed during syncope. In most patients, the likely cause was neurally-mediated, and the most frequent mechanism was a bradycardic reflex. In the other cases, a normal sinus rhythm was frequently recorded. Presyncope was not an accurate surrogate for syncope in establishing a diagnosis.

Adult↗
PubMed1999

Effect of etilefrine in preventing syncopal recurrence in patients with vasovagal syncope: a double-blind, randomized, placebo-controlled trial. The Vasovagal Syncope International Study.

BACKGROUND: Etilefrine is an alpha-agonist agent with a potent vasoconstrictor effect, which is potentially useful in preventing vasovagal syncope by reducing venous pooling and/or by counteracting reflex arteriolar vasodilatation. The present multicenter, randomized, placebo-controlled study was designed to evaluate the efficacy of this drug for the long-term management of patients with recurrent vasovagal syncope. METHODS AND RESULTS: In the 20 participating centers, 126 patients with recurrent vasovagal syncope (at least 3 episodes in the last 2 years) and a positive baseline head-up tilt response were randomly assigned to placebo (63 patients) or etilefrine at a dosage of 75 mg/d (63 patients) and were followed up for 1 year or until syncope recurred. The primary end-point of the study was the first recurrence of syncope. There were no differences between the 2 study groups in the patients' baseline characteristics. During follow-up, the group treated with etilefrine had a similar incidence of first syncopal recurrence to that of placebo group both in the intention-to-treat analysis (24% versus 24%) and in on- treatment analysis (26% versus 24%). Moreover, the median time to the first syncopal recurrence did not significantly differ between the 2 study groups (106 days in the etilefrine arm and 112 days in the placebo arm). CONCLUSIONS: Oral etilefrine is not superior to placebo in preventing spontaneous episodes of vasovagal syncope. Randomized controlled studies are essential to assess the real usefulness of any proposed therapy for patients with vasovagal syncope.

Adrenergic alpha-Agonists↗
PubMed2001

Different mechanisms of isoproterenol-induced and nitroglycerin-induced syncope during head-up tilt in patients with unexplained syncope: important role of epinephrine in nitroglycerin-induced syncope.

INTRODUCTION: A reduction in left ventricular volume and an increase in epinephrine levels have been reported in tilt-induced neurally mediated syncope. To compare the mechanisms of isoproterenol-induced and nitroglycerin-induced syncope during head-up tilt and to investigate the role of catecholamines, the temporal changes in plasma levels of norepinephrine and epinephrine and in left ventricular volume were measured. METHODS AND RESULTS: The first study population consisted of 90 patients with syncope of unknown etiology and 12 control subjects. The second study population consisted of 43 patients with unexplained syncope. In the first study, head-up tilt (80 degree angle) was conducted for 40 minutes, and norepinephrine and epinephrine levels were measured. In the second study, all patients were randomly allocated to either isoproterenol test (20 patients) or nitroglycerin test (23 patients) for 20-minute head-up tilt. Isoproterenol infusion was given at a rate of 1 to 3 microg/min. Intravenous infusion of nitroglycerin was started at 250 microg/hour with increasing dosages up to 1,500 microg/hour. Norepinephrine and epinephrine were measured in peripheral venous blood. Left ventricular volumes were measured by echocardiography with patients in the supine position and during head-up tilt every 1 minute. End-diastolic volume and end-systolic volume were calculated. In the first study, 61 patients demonstrated a positive response and 29 patients demonstrated a negative response. Plasma norepinephrine changes during head-up tilt were not significantly different, whereas epinephrine levels were significantly higher in the positive patients than in the negative and control subjects (148 +/- 118 pg/mL vs 66 +/- 31 pg/mL and 55 +/- 27 pg/mL). Thirteen of the 20 patients given isoproterenol and 15 of the 23 patients given nitroglycerin showed a positive head-up tilt (65.0% vs 65.2%; P = NS). During isoproterenol and nitroglycerin infusion head-up tilt, epinephrine in the positive group determined by the nitroglycerin test was significantly higher than that in the other three groups (103 +/- 38 pg/mL vs 60 +/- 33 pg/mL, 31 +/- 21 pg/mL, and 50 +/- 52 pg/mL). In contrast, end-systolic volume was significantly smaller in the positive group than in the other three groups based on findings of the isoproterenol test. CONCLUSION: The findings suggest that nitroglycerin triggers head-up tilt-induced syncope by increasing epinephrine levels, whereas isoproterenol induces syncope by decreasing left ventricular volume.

Adolescent↗
PubMed2000

New classification of haemodynamics of vasovagal syncope: beyond the VASIS classification. Analysis of the pre-syncopal phase of the tilt test without and with nitroglycerin challenge. Vasovagal Syncope International Study.

We believe that the pattern of blood pressure response to tilt during the time preceding the development of the vasovagal reaction may provide adjunctive diagnostic information. A group of 101 consecutive patients affected by syncope of uncertain origin underwent passive tilt testing for 45 min at 60 degrees followed, if negative, by oral (sublingual) trinitroglycerin (TNG) 0.4 microg with continuation of the test for 20 min. Three main patterns were observed: the classic (vasovagal) syncope pattern was observed in 36 patients who, during the preparatory phase, had a rapid and full compensatory reflex adaptation to upright position, resulting in stabilization of their blood pressure values until abrupt onset of the vasovagal reaction; the dysautonomic (vasovagal) syncope pattern was observed in 47 patients in whom steady-state adaptation to upright position was not possible. There was thus a progressive fall in their blood pressure until the occurrence of a typical vasovagal reaction; the orthostatic intolerance pattern was observed in 18 patients in whom there was a progressive fall in blood pressure, similar to that of the dysautonomic group, but this was not followed by a clear vasovagal reaction. Compared with the classic, the dysautonomic patients were older, had a higher prevalence of co-morbidities, a very much shorter history of syncopal episodes, and a prevalence of mixed and vasodepressor forms of the VASIS classification. The patients with orthostatic intolerance had clinical characteristics similar to the dysautonmic group but they could not be classified according to the VASIS classification. In conclusion, in patients with syncope, a variety of abnormal responses is observed during tilt testing, suggesting that different syndromes can be diagnosed by the test. A more detailed, although still arbitrary, classification may form the basis of a number of future drug and pacemaker trials, as well as help towards a greater understanding of the different mechanisms of tilt-induced syncope.

Autonomic Nervous System↗
PubMed1995

The value of the clinical history in the differentiation of syncope due to ventricular tachycardia, atrioventricular block, and neurocardiogenic syncope.

BACKGROUND: The present study was undertaken to identify and quantitate the symptoms associated with neurocardiogenic syncope, syncope due to ventricular tachycardia, and syncope resulting from atrioventricular block. PATIENTS AND METHODS: Eighty patients referred for evaluation of syncope in whom a diagnosis of neurocardiogenic syncope, atrioventricular block, or ventricular tachycardia was established were studied. Each patient was interviewed using a standard questionnaire. The clinical histories were then compared to identify which variables best differentiated the cause of syncope. RESULTS: The clinical histories of patients with syncope due to ventricular tachycardia and atrioventricular block were similar. Only age, the duration of prodromal symptoms, diaphoresis prior to syncope, and fatigue following syncope differed. In contrast, the clinical history in patients with neurocardiogenic syncope differed greatly from that obtained in patients with syncope due to atrioventricular block or ventricular tachycardia. Features of the clinical history that were predictive of syncope due to atrioventricular block or ventricular tachycardia were male sex, age > 54 years, < or = 2 episodes of syncope, and a duration of warning of < or = 5 seconds. Features of the clinical history predictive of syncope not due to ventricular tachycardia or atrioventricular block were palpitations, blurred vision, nausea, warmth, diaphoresis, or lightheadedness prior to syncope, and nausea, warmth, diaphoresis, or fatigue following syncope. CONCLUSIONS: The results of this study identify and compare the features of the clinical history obtained in patients with syncope due to ventricular tachycardia, atrioventricular block, and neurocardiogenic syncope and demonstrate that the clinical history is of value in distinguishing patients with these three causes of syncope.

Adult↗
PubMed1996

Is syncope a risk factor for poor outcomes? Comparison of patients with and without syncope.

OBJECTIVE: To determine whether syncope, independent of underlying comorbidities, is associated with increased mortality or other cardiovascular outcomes. PATIENTS AND METHODS: A prospective cohort study of patients with syncope and a group of patients without syncope matched with respect to age, gender, site of care (inpatient/ outpatient) and a cardiac disease index at an urban university medical center. Overall mortality, cardiac mortality, cardiovascular outcomes, and occurrence of syncope within 1 year of study enrollment were compared between the groups with Kaplan-Meier rates and Mantel-Cox statistics. RESULTS: The characteristics of 470 patients with syncope and the matched patients without syncope were similar except that the patients without syncope had more cardiac diseases than those with syncope (P = 0.002). Patients with and without syncope had similar rates of 1-year overall mortality (9% versus 11%, P = 0.29) and cardiac mortality (3% versus 6%, P = 0.08). In multivariate analyses, syncope was not a significant predictor of overall or cardiac mortality, but male gender, age > 55 years, and congestive heart failure were. One-year rates for other cardiovascular outcomes (myocardial infarction, congestive heart failure, cardiac arrest with survival, and cerebrovascular events) in patients with syncope were similar to those in patients without syncope (P > or = 0.2 for all comparisons). Patients with syncope had a 20.2% recurrence rate in 1 year as compared with a 2.1% rate for new syncope in patients without prior syncope (P < 0.00001). CONCLUSIONS: Syncope itself is not a risk factor for increased overall and cardiac mortality or cardiovascular events. Underlying heart diseases are risk factors for mortality regardless of whether the patient has syncope or not. The major focus of the evaluation of patients with syncope should be to identify and treat underlying heart diseases.

Cause of Death↗
PubMed2001

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.

Adolescent↗
PubMed1997

Syncope recurrence can better be predicted by history than by head-up tilt testing in untreated patients with suspected neurally mediated syncope.

BACKGROUND: Head-up tilt testing is widely used in the evaluation of patients with suspected neurally mediated syncope. Although it remains unclear which patients require medical therapy to prevent recurrent syncope, most centres initiate empiric medical therapy in all patients in whom neurally mediated syncope has been diagnosed. To determine the natural history of this condition, we followed 80 untreated patients. METHODS: All 80 study patients fulfilled the following inclusion criteria: (1) > or = 1 syncope in the upright position, (2) absence of structural heart disease, (3) unremarkable work-up for other known causes of syncope. Thirty-nine patients had a history of one episode of syncope (group A) and 41 > or = 2 episodes of syncope (group B). Head-up tilting was performed in all patients at 60 degrees for a maximum of 45 min without medical provocation ('Westminster Protocol'). RESULTS: Suspected neurally mediated syncope could be reproduced by tilt testing in four of 39 patients from group A vs 10 of 41 patients from group B (10% vs 24%, P = 0.1). Independent of the result of head-up tilt testing, all patients were prospectively followed without medical therapy. During 23 +/- 8 months follow-up, syncope recurred in four of 39 group A patients vs 22 of 41 group B patients (10% vs 54%, P < 0.05). The incidence of syncope during follow-up was not significantly different between patients with and without positive baseline tilt test (43% vs 30%, P = ns). CONCLUSIONS: (1) 90% of patients with a single episode of syncope remain free of recurrent syncope without medical therapy irrespective of the result of tilt testing. (2) About half of patients with a history of > or = 2 syncopal episodes have recurrent syncope and, thus, may be appropriate candidates for prophylactic medical therapy. (3) Although head-up tilt testing at 60 degrees for up to 45 min does not appear to be useful to predict recurrent syncope in untreated patients, it is still a useful test in its evaluation.

Adolescent↗
PubMed2001

Prevalence and correlates of syncope-related traumatic injuries in tilt-induced vasovagal syncope.

BACKGROUND: Vasovagal syncope represents the most common form of syncope in the general population and is usually considered as a benign affection. However, syncope-related traumatic injuries may represent a major complication of such a condition in a relevant percentage of cases. The aim of this study was to assess the prevalence and clinical correlates of syncope-related trauma in a cohort of consecutive patients with recurrent vasovagal syncope. METHODS: Three hundred and forty-six consecutive patients were studied in whom a diagnosis of vasovagal syncope was established. All subjects were interviewed with a standard questionnaire in order to collect all possible information about their clinical history and the occurrence of trauma during syncopal spells. RESULTS: Ninety-four of the 346 patients (27.2%) reported at least one syncope-related traumatic injury. In 31/346 cases (8.9%) the severity of trauma had determined hospital admission and surgical treatment. When compared to the rest of the study population, patients with syncope-related trauma showed a higher prevalence of male gender (p < 0.01), a higher absolute number (p < 0.01) and frequency (p < 0.01) of syncopal episodes in their history. Patients with trauma also reported a shorter duration of warning symptoms preceding syncope (p < 0.01), while showing a higher prevalence of positive cardioinhibitory response to tilt table testing (p < 0.01). Moreover, the number of syncope-related injuries was found to correlate significantly with the number of syncopal spells (r = 0.64, p < 0.01). CONCLUSIONS: Most practicing physicians consider vasovagal syncope as simply a benign affection in young people. However, such a clinical view should be partially revised, as recurrent vasovagal syncope is associated with significant trauma-related morbidity.

Adult↗
PubMed2002

Diagnostic implications of modified treadmill and head-up tilt tests in exercise-related syncope: comparative studies with situational and/or vasovagal syncope.

BACKGROUND: The precise pathophysiological basis of exercise-related vasodepressor syncope is not well understood. PURPOSE: The diagnostic values of head-up tilt and modified treadmill tests with abrupt termination were tested in patients with exercise-related syncope and compared with those of patients with situational or vasovagal syncope. PATIENTS AND METHODS: Diagnostic accuracies of head-up tilt and modified treadmill exercise tests were examined in 44 patients with unexplained syncope (26 men, 18 women, aged 46 19 years) and in 20 control subjects. Results for 18 patients with syncope during exercise (short-distance dash [n=7], jogging [n=3], going up stairs [n=6], swimming [n=1] or cycling [n=1]), defined as exercise-related syncope, were compared with those for 26 patients with exercise-unrelated syncope (including situational [n=7] and vasovagal [n=14] syncope). RESULTS: No differences were found between the clinical backgrounds of subjects with and those without exercise-related syncope. Head-up tilt testing had good diagnostic sensitivities, specificities and accuracies in both exercise-related and exercise-unrelated groups (84% versus 77%, 84% versus 85%, 84% versus 80%, respectively). The corresponding values of modified treadmill tests in the two groups were 78% versus 19% (P<0.05), 95% versus 95% and 86% versus 52% (P<0.05), respectively. The results of exercise tests were of limited diagnostic value for exercise-unrelated syncope. Beta-blockade had good short term efficacy in subjects with exercise-related syncope (nine of 15, 60%) as well as in subjects with exercise-unrelated syncope (seven of 10, 70%). CONCLUSIONS: Modified treadmill exercise testing is thought to be useful for diagnosing exercise-related syncope.

Adolescent↗
PubMed1993

Syncope in advanced heart failure: high risk of sudden death regardless of origin of syncope.

OBJECTIVES: The purpose of this study was to assess the importance of syncope as a warning sign for sudden death in advanced heart failure and to determine the relative importance of cardiac syncope and syncope from other causes. BACKGROUND: Despite remarkable advances in the pharmacologic approach to advanced heart failure, 20% to 40% of patients with advanced heart failure will die each year. In such patients, the relation between sudden death and the etiology of syncope has not been evaluated. METHODS: The relation of syncope to sudden death was evaluated in 491 consecutive patients with advanced heart failure (New York Heart Association functional class III or IV), no history of cardiac arrest and a mean left ventricular ejection fraction of 0.20 +/- 0.07. Patients were evaluated for the presence and origin of syncope. The severity of heart failure was assessed from serum sodium levels, ejection fraction, functional class and echocardiographic and hemodynamic variables. RESULTS: Sixty patients (12%) had a history of syncope; the condition had a cardiac origin in 29 (48%) and was due to other causes in 31 (52%). The origin of heart failure was coronary artery disease in 234 patients (48%) and dilated cardiomyopathy in 253 (51%) and its severity was similar in patients with and without syncope. During a mean follow-up interval of 365 +/- 419 days, 69 patients (14%) died suddenly and 66 patients (13%) died of progressive heart failure. The actuarial incidence of sudden death by 1 year was significantly greater in patients with (45%) than in those without (12%, p < 0.00001) syncope. In the Cox proportional hazards model, syncope predicted sudden death independent of atrial fibrillation, serum sodium, cardiac index, angiotensin-converting enzyme inhibition and patient age. The actuarial risk of sudden death by 1 year was similarly high in patients with either cardiac syncope or syncope from other causes (49% vs. 39%, p = NS). CONCLUSIONS: Patients with advanced heart failure are at especially high risk for sudden death regardless of the etiology of syncope.

Adult↗
PubMed2003

Pacemaker therapy for prevention of syncope in patients with recurrent severe vasovagal syncope: Second Vasovagal Pacemaker Study (VPS II): a randomized trial.

CONTEXT: Three previous small randomized trials have reported that pacemaker therapy is beneficial for patients with severe recurrent vasovagal syncope. However, because these trials were not double blind, they may have been biased in their assessment of outcomes and had a placebo effect of surgery. OBJECTIVE: To determine if pacing therapy reduces the risk of syncope in patients with vasovagal syncope. DESIGN, SETTING, AND PATIENTS: A randomized double-blind trial of pacemaker therapy in outpatients referred to syncope specialists at 15 centers from September 1998 to April 2002. In the year prior to randomization, patients had had a median of 4 episodes of syncope. Patients were followed up for up to 6 months. INTERVENTION: After implantation of a dual chamber pacemaker, 100 patients were randomly assigned to receive dual-chamber pacing (DDD) with rate drop response or to have only sensing without pacing (ODO). MAIN OUTCOME MEASURE: Time to first recurrence of syncope. RESULTS: No patients were lost to follow-up. Of the 52 patients randomized to ODO, 22 (42%) had recurrent syncope within 6 months compared with 16 (33%) of 48 patients in the DDD group. The cumulative risk of syncope at 6 months was 40% (95% confidence interval [CI], 25%-52%) for the ODO group and 31% (95% CI, 17%-43%) for the DDD group. The relative risk reduction in time to syncope with DDD pacing was 30% (95% CI, -33% to 63%; 1-sided P =.14). Lead dislodgement or repositioning occurred in 7 patients. One patient had vein thrombosis, another had pericardial tamponade leading to removal of the pacemaker system, and a third had infection involving the pacemaker generator. CONCLUSIONS: In this double-blind randomized trial, pacing therapy did not reduce the risk of recurrent syncope in patients with vasovagal syncope. Because of the weak evidence of efficacy of pacemaker therapy and the risk of complications, pacemaker therapy should not be recommended as first-line therapy for patients with recurrent vasovagal syncope.

Adult↗
PubMed1997

Timing of first recurrence of syncope predicts syncopal frequency after a positive tilt table test result.

OBJECTIVES: This study sought to determine whether the time to first recurrence of syncope after a positive isoproteremol-tilt table test result accurately predicts the eventual frequency of syncope. BACKGROUND: Both patient care and future clinical trials involving patients with neuromediated syncope will require a simple measure that reflects the frequency of syncope. The time from tilt table testing to the first recurrence of syncope might be such a measure. METHODS: A cohort of 46 patients with syncope, in a university outpatient clinic, who had at least one syncopal spell after a positive isoproterenol-tilt table test result were followed up for up to 6.5 years (mean [+/-SD] 48 +/- 14 months). The time from tilt table testing to the first recurrence of syncope was correlated. RESULTS: A total of 40 of 46 patients had more than one recurrent spell, with a median of eight recurrent spells. The time to the first syncopal spell predicted the frequency of spells with r = -0.79 (p < 0.001), whereas the time to the second spell predicted the frequency with r = -0.92 (p < 0.001). Patients who fainted within 1 month of tilt testing had a geometric mean frequency of 1.35 spells/month (95% confidence limits 0.49, 3.74) compared with patients who fainted 1 to 24 months after testing (0.12 spells/months; 95% confidence limits 0.07 to 0.18, p < 0.001). Finally, the frequency of syncopal spells bore no relation to the duration of follow-up. CONCLUSIONS: The time to the first recurrent spell predicts the frequency of syncopal spells after a positive tilt table test result, and the instantaneous risk of syncope is constant.

Adult↗
PubMed1999

The high cost of syncope: cost implications of a new insertable loop recorder in the investigation of recurrent syncope.

BACKGROUND: Patients with recurrent syncope frequently undergo extensive investigations that consume significant health care resources. Recent advances in long-term monitoring techniques have enhanced diagnostic yield in patients with infrequent symptoms. There is little information on the relative cost-effective profile of the investigative tools used in patients with syncope. METHODS: Two methods to determine health care costs in patients with syncope were used. In the first, health care resource utilization was determined in 24 patients with recurrent unexplained syncope and negative investigations who underwent insertion of the implantable loop recorder (ILR) during a pilot study of the feasibility of the device. The costs of investigations before, during, and after ILR implantation in each patient were calculated on the basis of median charges for an index investigation and a regression analysis of 1018 US Medicare hospital claims for syncope from 1993. Charges were converted to costs using a cost-to-charge ratio of 0.64. The second method was based on estimated costs per diagnosis and published diagnostic yields of 6 commonly applied tests in patients with syncope. A cohort simulation using theoretic models of 100 patients undergoing investigation for syncope was created to compare the diagnostic yield and cost per diagnosis of various diagnostic cascades. RESULTS: In the pilot study, the cost of investigation of syncope in the 2 years before ILR insertion was $7584 per patient. After the ILR was inserted, a diagnosis was obtained in 21 of 24 patients (diagnostic yield 88%). The cost of therapy was $2452, followed by a reduction in cost of care to $596 over 30 +/- 10 months of follow-up. In the second method, the diagnostic yield of individual tests ranged from 3% for echocardiography to 88% for the ILR. The cost per diagnosis obtained ranged from $529 for the external loop recorder to $73,260 for electrophysiologic testing in patients without structural heart disease. An approach to syncope similar to that of the ILR pilot study resulted in a cost per diagnosis of $3193 and a diagnostic yield of 98%. Performance of echocardiography in half of the patients and electrophysiologic testing only in the presence of structural heart disease reduced the cost to $2494 and retained a diagnostic yield of 98%. CONCLUSIONS: The cost of investigation of syncope is high. The ILR may reduce health care resource utilization by providing a diagnosis permitting definitive therapy. The cost per diagnosis profile of current diagnostic tests commonly used in patients with syncope is highly variable. A cost-effective approach to diagnosing this disorder can retain a high diagnostic yield with a reduction in resource utilization compared with a conventional approach.

Cost of Illness↗
PubMed2002

Comparison of hemodynamic adaptation to orthostatic stress in patients with hypertrophic cardiomyopathy with or without syncope and in vasovagal syncope.

This study was designed to investigate whether, in patients with hypertrophic cardiomyopathy (HC), tilt-induced volume unloading triggers a peripheral reflex similar to that seen in patients with a history of vasovagal syncope or rather acts through an intrinsic cardiac mechanism secondary to diastolic dysfunction. Thirty-seven patients with HC (10 with and 27 without a history of syncope), 10 patients with vasovagal syncope, and 9 controls underwent 70 degrees head-up tilt for 45 minutes during continuous radionuclide monitoring of left ventricular function. We focused on the initial 5 minutes into the tilt test, well before symptoms occurred, to exclude that the observed hemodynamic changes were the consequence rather than the cause of syncope. HC patients with previous syncope and vasovagal patients experienced significant hypotension after the initial 5 minutes of tilt. Only HC patients with a history of syncope had a significant decrease in cardiac output, which began at the initial stage of the test. Systemic vascular resistance decreased in vasovagal patients, but increased in the HC syncopal group. Baseline peak filling rate was lower (2.4 +/- 0.5 vs 3.3 +/- 1.1 stroke counts/s, p = 0.03) and a "pseudonormal" or a restrictive pattern of left ventricular filling was more frequent (70% vs 26%, p = 0.02) in HC patients with than without a history of syncope. Thus, significant hypotension or frank syncope during orthostatic stress in HC patients with a history of syncope is due to an early decrease in cardiac output, which occurs well before the onset of symptoms; such impaired hemodynamic adaptation seems to be related to diastolic dysfunction.

Adaptation, Physiological↗
PubMed2000

Clinical features of adenosine sensitive syncope and tilt induced vasovagal syncope.

AIM: To evaluate the possible relation between adenosine sensitive syncope and tilt induced vasovagal syncope. METHODS: An ATP test and a head up tilt test were performed in 175 consecutive patients with syncope of uncertain origin. The ATP test consisted of the rapid intravenous injection of 20 mg of ATP; a positive response was defined as the induction of a ventricular pause (maximum RR interval) >/= 6000 ms. The head up tilt test was performed at 60 degrees for 45 minutes; if negative, 0.4 mg oral glyceryl trinitrate spray was given and the test continued for a further 20 minutes; a positive response was defined as induction of syncope in the presence of bradycardia, hypotension, or both. RESULTS: Of the 121 patients with a positive response, 77 (64%) had a positive head up tilt alone, 18 (15%) had a positive ATP test alone, and in 26 (21%) both ATP and head up tilt were positive. Compared with the patients with isolated positive head up tilt, those with isolated positive ATP were older (mean (SD) age, 68 (10) v 45 (20) years), had a lower median number of syncopal episodes (2 v 3), a shorter median duration of syncopal episodes (4 v 36 months), a lower prevalence of situational, vasovagal, or triggering factors (11% v 64%), a lower prevalence of warning symptoms (44% v 71%), and a higher prevalence of systemic hypertension (22% v 5%) and ECG abnormalities (28% v 9%). The patients with a positive response to both tests had intermediate features. Of the 44 positive responses to the ATP test, atrioventricular block was the cause of the ventricular pause in 43; of the 29 positive cardioinhibitory responses to head up tilt, sinus arrest was present in 23 cases and atrioventricular block in six. CONCLUSIONS: ATP and head up tilt tests identify different populations of patients affected by syncope; these have different general clinical features, different histories of syncopal episodes, and different mechanism sites of action. Therefore, adenosine sensitive syncope and tilt induced vasovagal syncope are two distinct clinical entities.

Adenosine Triphosphate↗
PubMed1995

Syncope associated with exercise, a manifestation of neurally mediated syncope.

A retrospective review of patients evaluated at a university-based referral hospital was performed to assess the basis for syncope associated with exercise in young patients. Over an 8-year period, 54 consecutive young patients (aged 12 to 30 years) were referred for evaluation of frank syncope. Twelve patients had syncope associated with exercise (group I) and 42 patients had syncope not associated with exercise (group II). Patients underwent physical examination, chest x-ray, 2-dimensional echocardiography, and in selected cases, cardiac catheterization. Head-up tilt-table testing was performed in 11 of 12 group I patients. Ten group I patients had no evidence of structural heart disease: 9 of these 10 (90%) developed syncope with tilt-table testing. Head-up tilt-table testing was performed in 41 of 42 group II patients: 34 (83%) developed syncope with tilt-table testing. Standard cardiac electrophysiologic study was performed in 9 of 12 group I and in 30 of 42 group II patients, and identified a basis for syncope in only 2 group I and 1 group II patients. Among 9 group I patients with a positive result on head-up tilt-table testing and no evidence of structural heart disease (mean follow-up 4.3 years), 7 are without further episodes of syncope; 3 have discontinued medication and 5 have resumed at least limited exercise. In conclusion, susceptibility to tilt-induced syncope was the most frequent finding in young patients without structural heart disease referred for evaluation of exercise-associated syncope. Tilt-table testing may be an important diagnostic tool for the evaluation of these patients.

Adolescent↗