The role of clinical assessment and electrophysiology study in Brugada syndrome patients with syncope.

BACKGROUND: Cardiogenic syncope in Brugada syndrome (BrS) increases the risk of major events. Nevertheless, clinical differentiation between cardiogenic and vasovagal syncope can be challenging. We characterized the long-term incidence of major events in a large cohort of BrS patients who presented with syncope. METHODS: From a total of 474 patients, syncope was the initial manifestation in 135 (28.5%) individuals (43.9 ±â€¯13.9 years, 71.1% male). The syncope was classified prospectively as cardiogenic, vasovagal, or undefined if unclear characteristics were present. Clinical, electrocardiographic, genetic, and electrophysiologic features were analyzed. Cardiogenic syncope, sustained ventricular arrhythmias, and sudden death were considered major events in follow-up. RESULTS: In 66 patients (48.9%), the syncope was cardiogenic; in 51 (37.8%), vasovagal and in 18 (13.3%); undefined. The electrophysiology study (EPS) inducibility was more frequent in patients with cardiogenic syncope and absent in all patients with undefined syncope (28 [53.8%] vs 5 [12.2%] vs 0 [0%]; P < .01). During follow-up (7.7 ±â€¯5.6 years), only patients with cardiogenic syncope presented major events (16 [11.9%]). Among patients with inducible EPS, 7 (21.2%) presented major events (P = .04). The negative predictive value of the EPS for major events was 92.4%. The incidence rate of major events was 2.6% person-year. Parameters associated with major events included cardiogenic syncope (hazard ratio [HR] 6.3; 95% CI 1.1-10.4; P = .05), spontaneous type 1 electrocardiogram (HR 3.7; 95% CI 1.3-10.5; P = .01), and inducible EPS (HR 2.8; 95% CI 1.1-8.8; P = .05). CONCLUSIONS: An accurate syncope classification is crucial in BrS patients for risk stratification. In patients with syncope of unclear characteristics, the EPS may be helpful to prevent unnecessary implantable cardioverter defibrillators.

Assessment of Efficacy of Oral Rehydration Salts in Children With Neurally Mediated Syncope of Different Hemodynamic Patterns.

OBJECTIVE: To assess the efficacy of oral rehydration salts in children with neurally mediated syncope of different hemodynamic types. METHODS: Children with unexplained syncope or pre-syncope who visited or were hospitalized between March 2012 and February 2015 were enrolled in the study. Checked by the head-up tilt test, 105 children (aged 4-18 years, with a mean age of 11.96 ± 2.86 years) were diagnosed with neurally mediated syncope. Of them, 73 had vasovagal syncope (vasodepressor type in 46, mixed/cardioinhibitory types in 27), and 32 had postural orthostatic tachycardia syndrome. They were randomized into the oral rehydration salts plus health education group (n = 55) and the health education alone group (n = 50). All treated children were followed up. The follow-up time ranged from 6 to 25 (14.82 ± 6.13) months. Short-term effects were assessed according to the recurrence of clinical symptoms and reviews of head-up tilt test results 6 months after drug withdrawal. Long-term effects were compared between both groups of children with neurally mediated syncope. RESULTS: Short-term effect: No significant differences were found in subjective response rate and head-up tilt test negative results rate among different hemodynamic types ( P > .05). Long-term effect: Compared with the health education alone group, the cumulative response rate increased after treatment with oral rehydration salts ( P < .05). Among oral rehydration salts-treated children, the cumulative response rate was higher in those with vasodepressor vasovagal syncope than with mixed/cardioinhibitory vasovagal syncope ( P < .05). CONCLUSION: Compared with children with mixed/cardioinhibitory vasovagal syncope, oral rehydration salt is more suitable for those with vasodepressor vasovagal syncope.

Ambulatory electrocardiogram monitoring for syncope and collapse: a comparative assessment of clinical practice in UK and Germany.

Aims: Diagnostic ambulatory electrocardiogram (AECG) monitoring is widely used for evaluating syncope/collapse. In Europe, two sets of practice guidelines [National Institute for Health and Clinical Excellence (NICE) and European Society of Cardiology (ESC)] provide recommendations concerning optimal selection of AECG devices. However, whether practising physicians' select AECGs based on published guidelines is unclear. This study examined AECG use by Emergency Department (EDs) physicians and cardiologists in two European countries: Germany (D) and United Kingdom (UK). Methods and Results: A quantitative survey was undertaken in which 177 respondents participated (ED: UK 33, Germany 40; Cardiology: UK 54, Germany 50). The choice of AECG technology varied by specialty. Thus, among EDs, despite patients having daily symptoms, 20% (UK), 31% (D) of respondents chose an AECG other than Holter monitor. Conversely, when monitoring for infrequent events (

Regional Implementation of a Pediatric Cardiology Syncope Algorithm Using Standardized Clinical Assessment and Management Plans (SCAMPS) Methodology.

BACKGROUND: Pediatric syncope is common. Cardiac causes are rarely found. We describe and assess a pragmatic approach to these patients first seen by a pediatric cardiologist in the New England region, using Standardized Clinical Assessment and Management Plans (SCAMPs). METHODS AND RESULTS: Ambulatory patients aged 7 to 21 years initially seen for syncope at participating New England Congenital Cardiology Association practices over a 2.5-year period were evaluated using a SCAMP. Findings were iteratively analyzed and the care pathway was revised. The vast majority (85%) of the 1254 patients had typical syncope. A minority had exercise-related or more problematic symptoms. Guideline-defined testing identified one patient with cardiac syncope. Syncope Severity Scores correlated well between physician and patient perceived symptoms. Orthostatic vital signs were of limited use. Largely incidental findings were seen in 10% of ECGs and 11% of echocardiograms. The 10% returning for follow-up, by design, reported more significant symptoms, but did not have newly recognized cardiac disease. Iterative analysis helped refine the approach. CONCLUSIONS: SCAMP methodology confirmed that the vast majority of children referred to the outpatient pediatric cardiology setting had typical low-severity neurally mediated syncope that could be effectively evaluated in a single visit using minimal resources. A simple scoring system can help triage patients into treatment categories. Prespecified criteria permitted the effective diagnosis of the single patient with a clear cardiac etiology. Patients with higher syncope scores still have a very low risk of cardiac disease, but may warrant attention.

An approach to the clinical assessment and management of syncope in adults.

Syncope, defined as a brief loss of consciousness due to an abrupt fall in cerebral perfusion, remains a frequent reason for medical presentation. The goals of the clinical assessment of a patient with syncope are twofold: (i) to identify the precise cause in order to implement a mechanism-specific and effective therapeutic strategy; and (ii) to quantify the risk to the patient, which depends on the underlying disease,rather than the mechanism of the syncope. Hence, a structured approach to the patient with syncope is required. History-taking remains the most important aspect of the clinical assessment. The classification of syncope is based on the underlying pathophysiological mechanism causing the event, and includes cardiac, orthostatic and reflex (neurally mediated) mechanisms. Reflex syncope can be categorised into vasovagal syncope (from emotional or orthostatic stress), situational syncope (due to specific situational stressors), carotid sinus syncope(from pressure on the carotid sinus, e.g. shaving or a tight collar), and atypical reflex syncope (episodes of syncope or reflex syncope that cannot be attributed to a specific trigger or syncope with an atypical presentation). Cardiovascular causes of syncope may be structural(mechanical) or electrical. Orthostatic hypotension is caused by an abnormal drop in systolic blood pressure upon standing, and is defined asa decrease of >20 mmHg in systolic blood pressure or a reflex tachycardia of >20 beats/minute within 3 minutes of standing. The main causes of orthostatic hypotension are autonomic nervous system failure and hypovolaemia. Patients with life-threatening causes of syncope should be managed urgently and appropriately. In patients with reflex or orthostatic syncope it is important to address any exacerbating medication and provide general measures to increase blood pressure, such as physical counter-pressure manoeuvres. Where heart disease is found to bet he cause of the syncope, a specialist opinion is warranted and where possible the problem should be corrected. It is important to remember that in any patient presenting with syncope the main objectives of management are to prolong survival, limit physical injuries and prevent recurrences. This can only be done if a patient is appropriately assessed at presentation, investigated as clinically indicated, and subsequently referred to a cardiologist for appropriate management.

Feasibility of pulse presence and pulse strength assessment during head-up tilt table testing using an accelerometer located at the carotid artery.

Neurally mediated syncope (NMS) is a disorder of the autonomic regulation of postural tone, which is characterized by hypotension and/or bradycardia, resulting in cerebral hypo-perfusion and finally in a sudden loss of consciousness. Prediction of an impending NMS requires detection of pulse presence to derive heart rate (HR) as well as to assess the pulse strength (PS) related to systolic blood pressure (SBP) preferably from a single body location only. This paper analyses the basic feasibility of using a single accelerometer positioned above the common carotid artery to assess pulse strength and pulse rate towards NMS prediction. A physical model has been investigated to gain insights into expected signal morphologies and potential feature candidates vs. hemodynamic parameters such as SBP, pulse pressure (PP) and PR relevant for NMS detection. Model results are compared with first measurements obtained in a head-up tilt table test (HUTT) from a patient during impending syncope. We show that an accelerometer positioned at the carotid artery is a potential approach offering a valuable tool in syncope management.

Epidemiology of syncope/collapse in younger and older Western patient populations.

Syncope is a common problem which can be remarkably debilitating and associated with high health care costs; its true incidence is difficult to estimate due to variation in definition, differences in population prevalence and under reporting in the general population. The median peak of first syncope is around 15 years with a sharp increase after 70 years. Vasovagal syncope is the commonest cause of syncope for all age groups, but cardiac causes become more common with advancing age. The cumulative incidence of syncope ranges from 5% in females aged 20 to 29, up to 50% in females aged 80 and above. One-third of medical students report at least one syncopal episode in their life-time. The life-time cumulative incidence of syncope in women is almost twice that of men. Syncope accounts for up to 1-3% of hospital admissions and Emergency Room (ER) visits and in these settings is associated with cardiovascular co-morbidity and cardiovascular pharmacotherapy. In older adults syncope is a major cause of morbidity and mortality with enormous personal and wider health economic costs. Prevalence and incidence figures for syncope in older adults are confounded by an overlap with presentations classified as falls. In addition to injury and increasing dependency, quality-of-life studies consistently show that functional impairment in persons with recurrent syncope is similar to other chronic diseases.

Quality-of-life, health service use, and costs associated with syncope.

Syncope is a prevalent condition that is associated with high morbidity, health service use, and costs. Syncope negatively impacts multiple domains of quality-of-life, including physical health, mental health, and functional status. The morbidity associated with recurrent syncope is equivalent to chronic conditions such as severe rheumatoid arthritis and low back pain. Frequency of syncope events is related to worse morbidity, suggesting that effective diagnosis and management can improve quality-of-life. There is a high incidence of health service use associated with syncope, including 740,000 annual emergency department visits and 460,000 hospital admissions in the United States. Rates of admission and inpatient diagnostic testing are characterized by high variance and low clinical utility. Finally, the evaluation of syncope is associated with high costs. Hospital costs associated with the inpatient evaluation of syncope exceed $2.4 billion per year in the United States. Improved diagnostic and treatment algorithms are urgently needed to improve patient quality-of-life, reduce health service use, and lower costs related to the evaluation of syncope.

Implantable diagnostic monitors in the early assessment of syncope and collapse.

The implantable diagnostic monitor, or loop recorder (ILR) is a subcutaneous monitor capable of continuous ECG monitoring up to 3 years. It is an elegant investigative tool for the assessment of patients with recurrent, unexplained syncope in whom an arrhythmic cause needs to be excluded, and is now increasingly utilised very early in the diagnostic work-up of these patients, in line with current guidelines. This review examines the evidence underpinning these recommendations as well as the relevant clinical trials evaluating the use of the ILR in syncope. Continued research will be needed to validate its role as a first line investigation in a sub-select of syncopal patients, especially with the addition of remote monitoring capabilities.

Assessment of prevalence and pathological response to orthostatic provocation in patients with multiple sclerosis.

OBJECTIVE: The aim of this study was to determine the prevalence of pathologic response to orthostatic challenge in patients with relapsing remitting multiple sclerosis (RRMS) and the difference of the response in patients in relapse and remission. PATIENTS AND METHODS: We included 112 RRMS patients; group 1 included 53 patients in a relapse and group 2, 59 patients in remission. The head up tilt table test was used to provoke an orthostatic reaction. RESULTS: 71 (63%) patients (60.4% and 66% of relapse and remission subjects respectively) had a pathological response to orthostatic provocation. Syncope was found in 9 (17%) patients in group 1 compared to 22 (37.3%) in group 2 (p=0.014). Postural orthostatic tachycardia syndrome (POTS) was found in 17 (32%) patients in group 1 compared to 4 (6.8%) in group 2 (p=0.001). There was a significantly negative correlation between the Expanded Disability Status Scale (EDSS) and POTS (-0.201; p=0.034) and a positive correlation between the EDSS and syncope (0.190; p=0.044). CONCLUSION: The prevalence of distinct types of orthostatic autonomic dysfunction in different phases of RRMS seems to be in direct correlation with the EDSS. Furthermore, certain autonomic dysfunctions of orthostasis, more specifically syncope and POTS, tend to be increased in remission and relapse respectively.

[Diagnosis, sudden death risk stratification, and treatment of main long QT syndrome molecular-genetic variants].

Inherited long QT syndrome (LQTS) refers to the primary electrical diseases of the heart. It is characterized by QT prolongation on resting ECG and syncope due to life-threatening ventricular arrhythmias. This review focuses on diagnosis, differential diagnosis, risk stratification of sudden cardiac death, and treatment strategy of patients with most prevalent genetic fOrms of LQTS - LQT1, LQT2 and LQT3, which accounted for about 90% of all genetically confirmed cases. Recent advances in understanding of relationship between clinical, electrocardiographic features (on ECG, body surface mapping, stress test) and genetic variants of LQT presented. Characteristics of syncopal events and ECG features of LQTl, LQT2 and LQT3 in the majority of cases are helpful to make an appropriate choice for therapy, even before positive result of molecular genetic testing. Management has focused on the use of beta blockers as first-line treatment and exclusion of triggers of life-threatening arrhythmia which are specific for each molecular-genetic variant. Implantation of cardioverter defibrillator for secondary prevention of sudden death in the high-risk patients or patients with insufficient effect of antiarrhythmic therapy is required.

Auditory and vestibular assessment of patients with Ménière's disease who suffer Tumarkin attacks.

Tumarkin attacks are a feature of Ménière's disease that generate a significant degree of disability. The surprising nature of these events is the main reason behind their associated morbidity. In this study we set out to evaluate auditory and vestibular function, as well as disability, in a population of patients who suffer Tumarkin attacks. We found that patients who suffer Tumarkin attacks are more disabled and experience severer and more frequent autonomic symptoms and that their hearing level is significantly worse in the asymptomatic ear, especially at low frequencies. Accordingly, we consider that treatment must be carefully planned to be as conservative as possible in terms of hearing and that psychiatric and/or psychological treatment must always be considered as an adjuvant therapy.

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.

[Evaluation of autonomic cardiovascular functioning in patients with syncope]. / Valoracion de la funcion autonomica cardiovascular en pacientes con sincope.

INTRODUCTION: According to the current literature on the subject, patients with syncope suffer a dysfunction of the autonomic nervous system (ANS). Yet few studies offer a clear explanation of this dysfunction. Moreover, the evaluation of cardiovascular reflexes is a simple, useful method of studying the functional status of the ANS. This work was designed to evaluate the existence of dysautonomia in syncope patients by means of the autonomic cardiovascular stimulation tests; it has been the most comprehensive of those published to date. SUBJECTS AND METHODS: We studied 170 healthy volunteers and 188 patients with syncopes in the previous months, paired by age and sex. Cardiovascular stimulation tests were conducted, in accordance with Ewing and Clark's methodology, together with the cold test. A rating scale was included to evaluate the symptoms related to ANS involvement. RESULTS: Syncope patients display lower reactivity in tests involving cardiovascular stimulation of the ANS, regardless of whether they are taken individually or as a whole (67% in patients and 39% in controls) (p = 0.0001), except in the cold test. They also show an increase in the clinical symptoms of an autonomic origin (2.82 +/- 0.17) with respect to control subjects (0.78 +/- 0.09) (p = 0.0001). CONCLUSIONS: Our syncope patients have a dysautonomia that appears as a sympathetic and parasympathetic hypofunction. These findings confirm the value of autonomic cardiovascular stimulation tests in the study of these patients. Moreover, the search for other symptoms of autonomic involvement can be a great aid in evaluating this pathology.

Assessment of autonomic activity during daily life of patients with head-up tilt-induced prolonged asystole.

Autonomic activity is important in the pathophysiology of neurally mediated syncope (NMS) patients diagnosed by the head-up tilt (HUT) test, and prolonged systole induced by HUT is associated with a malignant vasovagal syndrome. This study investigated whether or not daily autonomic activity evaluated by heart rate variability (HRV) assessed through 24-hour ambulatory ECG monitoring was augumented in HUT-induced asystole (AS; > 30 s) and whether or not HRV differed between NMS patients with and without AS. Ambulatory ECG monitoring was performed in 176 patients with suspected NMS and in 62 age-matched healthy control subjects (C group, age: 36 +/- 13 yr), with HRV time and frequency domain indices measured within 48 hours of HUT. Six patients displayed prolonged AS (PAS group, age: 33 +/- 12 yr), and 109 patients had positive HUT (P group, age: 29 +/- 17 yr), while 61 patients had negative HUT (N group, age: 40 +/- 18 yr). Several HRV indices in the P group were higher than those in the N and C groups. However, HRV indices did not differ between the P group and the PAS group. It is concluded that impairment of autonomic activity specifically related to orthostatic stress could be important in the pathophysiology of HUT-induced prolonged asystole, while impairment of autonomic activity in daily life is not as important in NMS patients with HUT-induced prolonged asystole.

Understanding syncope. The pathophysiology & assessment of a challenging condition that EMS crews frequently encounter.

Syncope is a transient loss of postural tone and consciousness following which, by definition, the patient has a spontaneous recovery without intervention. The differential diagnosis of syncope is broad and spans benign to life-threatening conditions. Identifying and treating serious conditions that may mimic syncope and identifying patients at high risk (cardiac syncope) are challenges that face prehospital providers. A comprehensive history and physical provide the most useful information in making these distinctions. Syncope is a symptom, not a disease; therefore, treatment must be targeted to the underlying disease process.

[Assessment of autonomic nervous function during orthostatic stress in pilots with history of syncope].

OBJECTIVE: To assess the role of autonomic nervous function during orthostatic tolerance tests (OTT) in pilots with history of G-induced loss of consciousness (G-LOC) or vasovagal syncope (VVS). METHOD: The relation between heart rate variability (HRV) and outcome of OTT result were compared among 3 groups of cases: 1) 30 patients with history of syncope and positive OTT as patient group (PG); 2) 20 cases with history of syncope but negative OTT result as negative group (NG); 3) 15 age-, sex-, flight plane model-, flight time-matched healthy pilots as healthy control (HC). OTT results and HRV, heart rate (HR), systolic blood pressure (SBP) and diastolic blood pressure (DBP) before and after OTT and their time and frequency domain were compared and analyzed among the three groups. RESULT: HR, SBP, and DBP were not significantly different (P>0.05) among the three groups before OTT. But during OTT, HR in PG was higher than those in NG and HC (P<0.01), SBP and DBP in PG were lower than those in NG and HC (P<0.01). 24 h continuous RR interval standard difference (SDNN), HRV triangle index (HRVI), and interval average value in PG were significantly lower than those in NG and HC; Power spectrum analysis of mean 1 h value for low frequency part (LF) and high frequency part (HF) were not significantly different among three groups, but LF/HF ratio in PG was higher than that in NG or HC (P<0.05). CONCLUSION: It is suggested that G-LOC and VVS may be due to increase in sympathetic tone and decrease in parasympathetic tone during orthostatic stimulation, as resulted from autonomic nervous dysfunction.

Assessment of left ventricular volume by an ambulatory radionuclide monitoring system during head-up tilt in patients with unexplained syncope: relation to autonomic activity assessed by heart rate variability.

BACKGROUND: Decreased left ventricular volume during head-up tilt plays an important role in triggering syncope in patients with neurally mediated syncope. However, precise changes in left ventricular volume during head-up tilt have not been well investigated. This study was conducted to test the hypothesis that the decline in left ventricular volume during tilt could trigger ventricular mechanoreceptor activation. METHODS AND RESULTS: To investigate the mechanisms of tilt-induced syncope, we measured the temporal changes in left ventricular volume, ejection fraction, cardiac output, and heart rate variability indices during head-up tilt in 25 patients with syncope of undetermined etiology. Eleven patients had a cardioinhibitory response (CI group), 7 patients showed a vasodepressor response (VD group), and 7 patients demonstrated a negative response (NG group). Before syncope, ejection fraction increased most in the CI group, the left ventricular end-diastolic volume declined most in the VD group (VD group, -11.0% +/- 3.3%; CI group, -2.8% +/- 4.8%; NG group, -3.4% +/- 2.2%; P <.005), and the high-frequency spectra increased most in the CI group (CI group, 25.0% +/- 21.0%; VD group, -4.1% +/- 11.7%; NG group, -5.3% +/- 12.7%; P <.01). The vasodepressor response was dependent on left ventricular volume, whereas the cardioinhibitory response was related to the vagal activity reflected by high-frequency spectra. CONCLUSIONS: The precise evaluation of left ventricular volume by an ambulatory radionuclide monitoring system combined with a heart rate variability analysis is considered useful for clarifying the pathophysiology of neurally mediated syncope.

Predictive value of presyncope in patients monitored for assessment of syncope.

BACKGROUND: The purpose of this study was to assess the diagnostic value of recording the cardiac rhythm during presyncope in patients undergoing monitoring for undiagnosed syncope. METHODS AND RESULTS: Eighty-five patients (age, 59 +/- 18 years; 44 men, 41 women) with recurrent unexplained syncope underwent prolonged monitoring with an implantable loop recorder. Patients were examined for syncope, which was either recurrent or associated with at least 2 presyncopal episodes. Patients had a mean of 5.1 +/- 5.5 syncopal episodes in the previous 12 months, and 70% of patients had symptoms for >2 years. Sixty-two (73%) patients had recurrent symptoms during a 12-month follow-up period. Of 150 recurrent events captured by the implantable loop recorder, there were 38 (25%) episodes of syncope and 112 (75%) episodes of presyncope. Syncope alone recurred in 12 patients, presyncope in 25, and both in 16. An arrhythmia was present in 64% of syncopal events (bradycardia in 16, tachycardia in 2) versus 25% for presyncopal events (bradycardia in 7, tachycardia in 3, P =.001). An arrhythmia was detected in 9 (56%) of the 16 patients with both syncope and presyncope, which was present in all recorded episodes of syncope compared with 6 of 9 presyncopal episodes. Patient-related failure to freeze the device after symptoms occurred in 21 (36%) of 59 syncopal events compared with 15 (12%) of 127 presyncopal events (P =.0001). CONCLUSIONS: Syncope is more likely to be associated with an arrhythmia than is presyncope in patients undergoing extended monitoring. Presyncope is a nonspecific end point that is frequently associated with sinus rhythm. Patients undergoing extended monitoring for syncope should continue to be monitored after an episode of presyncope unless an arrhythmia is detected.