Usefulness of a tilt training program for the prevention of refractory neurocardiogenic syncope in adolescents: A controlled study

The efficacy of non-pharmacological and non-pacing therapies in preventing vasovagal syncope: Tilt training, physical counter pressure maneuvers, and yoga - A systematic review and meta-analysis

BACKGROUND

Vasovagal syncope (VVS) is a prevalent condition characterized by a sudden drop in blood pressure and heart rate, leading to a brief loss of consciousness and postural control. Recurrent episodes of VVS significantly impact the quality of life and are a common reason for emergency department visits. Non-pharmacological interventions, such as tilt training, physical counter pressure maneuvers, and yoga, have been proposed as potential treatments for VVS. However, their efficacy in preventing VVS remains uncertain.

METHODS

A systematic review and meta-analysis were conducted following PRISMA guidelines. PubMed, Web of Science, and Embase were searched up to March 2023 for randomized controlled trials comparing non-pharmacological interventions with control in preventing VVS recurrence. The primary outcome was the recurrence rate of VVS episodes.

RESULTS

A total of 1130 participants from 18 studies were included in the meta-analysis. The overall mean effect size for non-pharmacological interventions versus control was 0.245 (95 % CI: 0.128-0.471, p-value <0.001). Subgroup analysis showed that yoga had the largest effect size (odds ratio 0.068, 95 % CI: 0.018-0.250), while tilt training had the lowest effect size (odds ratio 0.402, 95 % CI: 0.171-0.946) compared to control. Physical counter pressure maneuvers demonstrated an odds ratio of 0.294 (95 % CI: 0.165-0.524) compared to control.

CONCLUSION

Non-pharmacological interventions show promise in preventing recurrent VVS episodes. Yoga, physical counter pressure maneuvers, and tilt training can be considered as viable treatment options. Further research, including randomized studies comparing pharmacological and non-pharmacological approaches, is needed to evaluate the safety and efficacy of these interventions for VVS treatment.

A case of vasovagal syncope associated with carotid sinus hypersensitivity: Effectiveness of tilt training and subsequent squatting

A 43-year-old man fainted on a train and was transported to our hospital by an ambulance. No structural heart diseases or neurological abnormalities were observed. Electrocardiogram on admission demonstrated a junctional escape rhythm with bradycardia at 39 bpm. Sick sinus syndrome was excluded from electrophysiological studies. He had lifelong episodes of recurrent syncope that occurred due to emotional stress in daily life and pain associated with medical procedures. Since both the head-up tilt and carotid sinus massage tests showed a positive response, he was diagnosed with vasovagal syncope (VVS) and carotid sinus hypersensitivity. He was encouraged to continue the modified tilt training at home, which included leaning on the wall and squatting if leaning was intolerant. Thereafter, syncope was not observed in his daily life. This case highlights the importance of an accurate diagnosis, full education, and home training for recurrent syncope. This case also suggests that the carotid sinus may be involved in the neural network that causes VVS.

Learning objective

Reflex syncope includes both vasovagal syncope (VVS) and carotid sinus syndrome (CSS); however, VVS is discriminated from CSS according to current guidelines. We encountered a case of VVS associated with carotid sinus hypersensitivity. Recurrent syncope disappeared with modified tilt training characterized by conventional tilting and subsequent squatting when tilting was intolerant. This case indicates that the carotid sinus may be involved in the neural network responsible for VVS.

Biomarkers and Hemodynamic Parameters in the Diagnosis and Treatment of Children with Postural Tachycardia Syndrome and Vasovagal Syncope

In children, vasovagal syncope and postural tachycardia syndrome constitute the major types of orthostatic intolerance. The clinical characteristics of postural tachycardia syndrome and vasovagal syncope are similar but their treatments differ. Therefore, their differential diagnosis is important to guide the correct treatment. Therapeutic methods vary in patients with the same diagnosis because of different pathomechanisms. Hence, in patients with vasovagal syncope or postural tachycardia syndrome, routine treatments have an unsatisfactory efficacy. However, biomarkers could increase the therapeutic efficacy significantly, allowing for an accurate and detailed assessment of patients and leading to improved therapeutic effects. In the present review, we aimed to summarize the current state of research into biomarkers for distinguishing the diagnosis of pediatric vasovagal syncope from that of postural tachycardia syndrome. We also discuss the biomarkers that predict treatment outcomes during personalized therapy for each subtype.

Clinical Significance of the Head-Up Tilt Test in Improving Prognosis in Patients with Possible Neurally Mediated Syncope

Simple Summary

Several diseases can cause syncope, which is commonly known as fainting; however, syncope triggered by a reflex mechanism, also termed neurally mediated syncope (NMS), is one of the most common forms. While NMS is considered a benign disease, it can cause critical clinical events, such as severe trauma due to syncope. The head-up tilt test (HUTT) is one of the modalities for the diagnosis of NMS. The clinical significance of HUTT in the prognosis of NMS, such as recurrence rate of syncope and mortality, are still to be elucidated. This research aimed to clarify the value of HUTT for the diagnosis of NMS, and to investigate the prognosis of patients with NMS by analyzing the data of 101 patients with syncope and their close long-term (four years at the longest) follow-up. Furthermore, as insertable cardiac monitors (ICMs) are considered effective in patients with syncope, this study also aimed to evaluate the usefulness of ICM in patients with negative HUTT results. Finally, our research contributes to the improvement of the clinical management for patients with syncope.

Abstract

Syncope is commonly encountered in daily clinical practice. Depending on its etiology (benign or life-threatening conditions or environmental triggers), syncope can be neurally mediated (reflex), cardiac, or orthostatic. Furthermore, neurologic disease can cause symptoms that mimic syncope. However, there is limited research on neurally mediated syncope (NMS), which is considered a benign disorder, and close follow-ups are rarely performed. NMS can cause serious clinical events, including severe trauma and car accidents. The head-up tilt test (HUTT) is the gold standard for diagnosing NMS; however, its clinical significance remains unknown, and its relevance to NMS prognosis requires further research. This retrospective study aimed to assess the clinical significance of the HUTT for NMS. We reviewed the charts of 101 patients who underwent HUTT at Tokai University Hospital in Japan between January 2016 and March 2019. During the HUTT, 72 patients (69.2%) experienced syncope. Patients were followed up for 886.1 ± 457.7 days (interquartile range: 518–1293 days). The syncope recurrence rate was 16.9%; however, no significant difference was observed between the two groups (HUTT positive vs. negative) (13.8% vs. 18.1%, p = 0.772). Four of 29 (13.9%) and two of 72 (2.8%) patients in the negative and positive HUTT groups, respectively, experienced cardiac events (p = 0.019). Negative HUTT results may assist in anticipating unexpected clinical events within a few years. A negative HUTT result may allow us to reconsider the NMS diagnosis based on clinical information. Close outpatient follow-up of patients with negative HUTT results is warranted.

Diagnostic and therapeutic approach to cardioinhibitory reflex syncope: A complex and controversial issue

Syncope is defined as a transient loss of consciousness due to global cerebral hypoperfusion and is one of the leading causes of emergency department admission. The initial approach should focus on excluding non-syncopal causes for loss of consciousness and risk stratification for cardiac cause, in order to ensure an appropriate etiological investigation and therapeutic approach. Vasovagal syncope (VVS), the most common type of syncope, should be assumed once other causes are excluded. Pathophysiologically, the vasovagal reflex is the result of a paradoxical autonomic response, leading to hypotension and/or bradycardia. VVS has not been shown to affect mortality, but morbidity may be considerable in those with recurrent syncopal episodes. The management of VVS includes both non-pharmacological and pharmacological measures that act on various levels of the reflex arc that triggers the syncopal episode. However, most are of uncertain benefit given the scarcity of high-quality supporting evidence. Pacemaker therapy may be considered in recurrent refractory cardioinhibitory reflex syncope, for which it is currently considered a robust intervention, as noted in the European guidelines. Non-randomized and unblinded studies have shown a potential benefit of pacing in recurrent VVS, but double-blinded randomized controlled trials have not consistently demonstrated positive results. We performed a comprehensive review of the current literature and recent advances in cardiac pacing and pacing algorithms in VVS, and discuss the diagnostic and therapeutic approach to the complex patient with recurrent VVS and reduced quality of life.

Acceleration Index Predicts Efficacy of Orthostatic Training on Vasovagal Syncope in Children

OBJECTIVE

To explore the value of the acceleration index as a predictor of therapeutic response to orthostatic training in children with vasovagal syncope (VVS).

STUDY DESIGN

Thirty-three children with VVS were recruited and treated with orthostatic training. The therapeutic response of each patient was evaluated after 3 months of treatment. A Pearson correlation was calculated between the acceleration index and the severity of VVS. The value of the acceleration index in predicting the therapeutic response to orthostatic training was assessed by analysis of the receiver operating characteristic curve.

RESULTS

Among the 33 children with VVS, 20 were found to be responders and the remaining were nonresponders. The mean acceleration index was significantly lower in responders compared with nonresponders (21.10 ± 6.61 vs 31.36 ± 9.00; P = .001) and it was negatively correlated with positive response time in the head-up tilt test, with systolic blood pressure and with diastolic blood pressure at positive response time in the head-up tilt test (P < .05). The receiver operating characteristic curve for the predictive value of the acceleration index showed that the area under the curve was 0.827 (95% CI, 0.676-0.978; P = .002), and a cutoff value of the acceleration index of 26.77 yielded a sensitivity of 85.0% and a specificity of 69.2%.

CONCLUSIONS

The acceleration index may be useful for predicting the efficacy of orthostatic training on VVS in children.

Vestibular Activation Habituates the Vasovagal Response in the Rat

Vasovagal syncope is a significant medical problem without effective therapy, postulated to be related to a collapse of baroreflex function. While some studies have shown that repeated static tilts can block vasovagal syncope, this was not found in other studies. Using anesthetized, male Long–Evans rats that were highly susceptible to generation of vasovagal responses, we found that repeated activation of the vestibulosympathetic reflex (VSR) with ±2 and ±3 mA, 0.025 Hz sinusoidal galvanic vestibular stimulation (sGVS) caused incremental changes in blood pressure (BP) and heart rate (HR) that blocked further generation of vasovagal responses. Initially, BP and HR fell ≈20–50 mmHg and ≈20–50 beats/min (bpm) into a vasovagal response when stimulated with Sgv\S in susceptible rats. As the rats were continually stimulated, HR initially rose to counteract the fall in BP; then the increase in HR became more substantial and long lasting, effectively opposing the fall in BP. Finally, the vestibular stimuli simply caused an increase in BP, the normal sequence following activation of the VSR. Concurrently, habituation caused disappearance of the low-frequency (0.025 and 0.05 Hz) oscillations in BP and HR that must be present when vasovagal responses are induced. Habituation also produced significant increases in baroreflex sensitivity (p < 0.001). Thus, repeated low-frequency activation of the VSR resulted in a reduction and loss of susceptibility to development of vasovagal responses in rats that were previously highly susceptible. We posit that reactivation of the baroreflex, which is depressed by anesthesia and the disappearance of low-frequency oscillations in BP and HR are likely to be critically involved in producing resistance to the development of vasovagal responses. SGVS has been widely used to activate muscle sympathetic nerve activity in humans and is safe and well tolerated. Potentially, it could be used to produce similar habituation of vasovagal syncope in humans.

Home Orthostatic Training in Elderly Patients with Vasovagal Syncope - A Prospective Randomised Controlled Trial

Aim: The aim of this study was to assess the effect of home orthostatic training (HOT) on autonomic reflexes in elderly patients with vasovagal syncope (VVS). Methods: Design and Setting: A single-blind randomised control trial was conducted at Eastbourne District General Hospital, East Sussex NHS Trust. Patients: Individuals with recurrent syncope underwent tilt-table testing between August 2007 and October 2009.Those with at least two syncopal episodes and tilt-test proven VVS were recruited. Participants were divided into those aged >65 years (O65) and those aged <65 years (U65). Interventions: Patients in the O65 group were randomised 1:1 to receive active HOT (O65+) or sham HOT (O65-). The U65 group received active HOT. Participants performed HOT/sham HOT and recorded their training and symptoms. Patients had a repeat tilt test at 3 months. Outcome Measures: Time to syncope at repeat tilt-table testing, low-frequency heart rate variability (LF-HRV), high-frequency heart rate variability (HF-HRV), mean upslope baroreflex sensitivity (BRS) and mean downslope BRS were assessed. Results: A total of 106 patients with recurrent syncope underwent tilt-table testing. Of these, 45 consecutive patients (30 in the O65 group and 15 in the U65 group) were recruited. Two, one and three patients withdrew or were lost-to-follow-up in the O65+, O65-, and U65 groups, respectively. Symptomatic benefit occurred in four (31 %) of the O65+, four (29 %) of the O65-, and six (50 %) of the U65. None of the autonomic measures changed significantly in any group. No difference was seen with HF-HRV, LF-HRV mean upslope BRS and mean downslope BRS. Fifty per-cent of the O65+ group stopped training because of back pain. Time constraint (25 %) was the most common reason for cessation in the U65 group. Conclusions: Despite good tilt training compliance, no improvement in autonomic measures in any group was shown. The most common reason for cessation of training was back pain in the elderly groups. This study does not support the use of HOT in elderly patients.

Managing the military patient with syncope

Syncope is a relatively common occurrence in military populations. It is defined as a transient loss of consciousness due to global cerebral hypoperfusion, characterised by a rapid onset, short duration and a spontaneous and complete recovery. While the symptom of syncope is easily elicited, discovering the mechanism can be more problematic and may require a plethora of diagnostic tests. The aim of this paper is to review current evidence pertaining to the classification, investigation and management of syncope, from a military perspective. Emphasis is placed on assisting primary healthcare professionals in the assessment and management of syncope, in the UK and on operations, while providing explicit guidance on risk. The occupational limitations required in safely managing patients with syncope are stressed along with the potential long-term limitations.

Physical training as non-pharmacological treatment of neurocardiogenic syncope

BACKGROUND

Characterized as a sudden and temporary loss of consciousness and postural tone, with quick and spontaneous recovery, syncope is caused by an acute reduction of systemic arterial pressure and, therefore, of cerebral blood flow. Unsatisfactory results with the use of drugs allowed the nonpharmacological treatment of neurocardiogenic syncope was contemplated as the first therapeutic option.

OBJECTIVES

To compare, in patients with neurocardiogenic syncope, the impact of a moderate intensity aerobic physical training (AFT) and a control intervention on the positivity of head-up tilting test (HUT) and orthostatic tolerance time.

METHODS

Were studied 21 patients with a history of recurrent neurocardiogenic syncope and HUT. The patients were randomized into: trained group (TG), n = 11, and control group (CG), n = 10. The TG was submitted to 12 weeks of AFT supervised, in cycle ergometer, and the CG to a control procedure that consisted in 15 minutes of stretching and 15 minutes of light walk.

RESULTS

The TG had a positive effect to physical training, with a significant increase in peak oxygen consumption. The CG did not show any statistically significant change before and after the intervention. After the intervention period, 72.7% of the TG sample had negative results to the HUT, not having syncope in the revaluation.

CONCLUSION

The program of supervised aerobic physical training for 12 weeks was able to reduce the number of positive HUT, as it was able to increase tolerance time in orthostatic position during the HUT after the intervention period.

Tilt-table test: its role in modern practice

Syncope is a major healthcare problem with significant morbidity, mortality and healthcare cost. It is a common symptom with a complex pathophysiology and, therefore, several aetiologies. Tilt-table testing (TTT) is an important, yet perhaps not widely-used, test that forms part of the management of syncope. We sought to assess the utilisation of this test in our institution for the investigation of patients with syncope, to study the referral patterns and the outcomes and usefulness of the TTT in a real-life setting. We undertook a retrospective study of all the TTT that were performed in our institution between January 2009 and October 2009. Of the 69 patients in which TTT was performed, 14 (20%) presented with presyncope, 24 (35%) with a single episode of syncope and 24 (44%) with multiple episodes. The average age was 57.2 years and 64% were female. Of the total patients, 35 (51%) had an abnormal TTT. Of the patients with normal TTT, four had internal loop recorders and six were referred to other medical specialities. The remaining patients (49%) had no formal diagnosis and were referred back to their general practitioner. TTT remains a common test modality and has great value when undertaken in the correct clinical context. This underlines the importance of a detailed clinical history. The European Society of Cardiology guidelines ensure a methodical and rational approach to syncopal patients and aide in choosing the right patient for the right test.

Treatment of neurally mediated reflex syncope

Neurally mediated reflex syncope, more commonly known as vasovagal syncope (VVS), remains the most common cause of transient loss of consciousness and syncope in all age groups. Most evidence assessing treatment of VVS derived from randomized clinical trials is limited. Multiple modalities of both nonpharmacologic and pharmacologic strategies have been tested, with conflicting results. The treatment of VVS has been directed toward interventions that interrupt the reflex response at different levels, hypothetically preventing the onset of syncope. This article reviews the available evidence of the different nonpharmacologic and pharmacologic therapies available for the treatment of recurrent VVS.

[Tilt training increases vasoconstrictor reserve in patients with neurocardiogenic syncope]

Neurocardiogenic syncope (NCS) is a common clinical entity resulting from an excessive reflex autonomic response, particularly during orthostatism. Treatment options are controversial and of limited effectiveness. Tilt training (TT) is a promising option to treat these patients. However, its mechanism of action and clinical impact remain unclear.

OBJECTIVE

To characterize hemodynamic and autonomic responses during a TT program in patients with NCS refractory to conventional measures.

METHODS

We studied 28 patients (50% male, mean age 41±14 years) without structural heart disease, with NCS documented by tilt testing. The TT program included 9 tilt sessions (3 times a week, 30 min) (60° - 6 sessions, 70° - 3 sessions), under ECG and blood pressure monitoring combined with home orthostatic self-training and 10° head-up during sleep. Systolic volume, cardiac output, total peripheral resistance, baroreflex sensitivity and heart-rate variability were computed. Patients were reassessed at 1 month and every 6 months for a maximum of 36 months (24±12 months).

RESULTS

Over the course of the TT program there was a significant increase in total peripheral resistance (1485±225 vs. 1591±187 dyn·s·cm(-5), p<0.05), with a decrease in standard deviation (206±60 vs. 150±42, p<0.05). During follow-up, syncope recurred in five patients (19%), with a significant reduction in the number of episodes (4.0±3.2/patient in the 12 months before TT vs. 1.4±0.8/patient post-TT, p<0.05).

CONCLUSION

In refractory NCS, TT may be an effective therapeutic option, with long-term benefits. These results appear to be due to an increase in vasoconstrictor reserve combined with a reduction in its variance.

Are treatments for vasovagal syncope effective? A meta-analysis

BACKGROUND

Therapies used to treat vaso-vagal syncope (VVS) recurrence have not been proven effective in single studies.

METHODS

Comprehensive search of PubMed, EMBASE and Cochrane Central databases of published trials was done. Randomized or non-randomized studies, comparing the intervention of interest to control group(s), with the endpoint of spontaneous recurrence or syncope on head-up tilt test, were included. Data were extracted on an intention-to-treat basis. Study heterogeneity was analyzed by Cochran's Q statistics. A random-effect analysis was used.

RESULTS

α-adrenergic agonists were found effective (n=400, OR 0.19, CI 0.06-0.62, p<0.05) in preventing VVS recurrence. β-blockers were not found to be effective when only randomized studies comparing β-blockers to non-pharmacologic agents were assessed (9 studies, n=583, OR 0.48, CI 0.22-1.04, p=0.06). Tilt-training had no effect when only randomized studies were considered (4 studies, n=298, OR 0.47, CI 0.21-1.05, p=0.07). Selective serotonin reuptake inhibitors were found effective (n=131, OR 0.28, CI 0.10-0.74, p<0.05), though the analysis contained only 2 studies. Pacemakers were found effective in preventing syncope recurrence when all studies were analyzed (n=463, OR 0.13, CI 0.05-0.36, p<0.05). However, studies comparing active pacemaker to sensing mode only did not show benefit (3 studies, n=162, OR 0.45, CI 0.09-2.14, p=0.32).

CONCLUSIONS

This meta-analysis highlights the totality of evidence for commonly used medications used to treat VVS, and the requirement for larger, double-blind, placebo controlled trials with longer follow-up.

Syncope in adults: systematic review and proposal of a diagnostic and therapeutic algorithm

This review aims to provide a practical and up-to-date description on the relevance and classification of syncope in adults as well as a guidance on the optimal evaluation, management and treatment of this very common clinical and socioeconomic medical problem. We have summarized recent active research and emphasized the value for physicians to adhere current guidelines. A modern management of syncope should take into account 1) use of risk stratification algorithms and implementation of syncope management units to increase the diagnostic yield and reduce costs; 2) early implantable loop recorders rather than late in the evaluation of unexplained syncope; and 3) isometric physical counter-pressure maneuvers as first-line treatment for patients with neurally-mediated reflex syncope and prodromal symptoms.

Management and therapy of vasovagal syncope: A review

Vasovagal syncope is a common cause of recurrent syncope. Clinically, these episodes may present as an isolated event with an identifiable trigger, or manifest as a cluster of recurrent episodes warranting intensive evaluation. The mechanism of vasovagal syncope is incompletely understood. Diagnostic tools such as implantable loop recorders may facilitate the identification of patients with arrhythmia mimicking benign vasovagal syncope. This review focuses on the management of vasovagal syncope and discusses the non-pharmacological and pharmacological treatment options, especially the use of midodrine and selective serotonin reuptake inhibitors. The role of cardiac pacing may be meaningful for a subgroup of patients who manifest severe bradycardia or asystole but this still remains controversial.

Home orthostatic training in chronic fatigue syndrome--a randomized, placebo-controlled feasibility study

BACKGROUND

Orthostatic (Tilt)-training is an effective treatment for neurally mediated hypotension (NMH). NMH is a frequent finding in chronic fatigue syndrome (CFS). We evaluated home orthostatic training (HOT) in CFS in a randomized placebo-controlled feasibility study.

METHODS

Thirty-eight patients with CFS (Fukuda Criteria) were randomly allocated to daily tilt training (n = 19) or sham training (n = 19) for 6 months. Haemodynamic responses to standing were performed in all subjects using continuous technology (Taskforce) at enrolment, week 1, 4 and 24. Symptom response and compliance were assessed using diaries.

RESULTS

Two patients (one from each arm) withdrew from the study. Fourteen patients in each group complied completely or partially, and patients found the training manageable and achievable. Compared to the sham group, blood pressure while standing dropped to 8.0 mmHg less in the HOT group at 4 weeks (95% CI: 1.0 to 15.0, P = 0.03). At 4 weeks, the HOT group had higher total peripheral resistance compared to the sham group; mean difference 70.2, 95% CI: -371.4 to 511.8. Changes were maintained at 6 months. There was no significant difference in fatigue between groups at 4 weeks (mean difference 1.4, 95% CI: -13.5 to 16.2), but there was a trend towards improvement in fatigue at 6 months. Compliers had lower fatigue compared to non-compliers.

CONCLUSIONS

A placebo-controlled study of HOT in CFS is feasible. HOT is well tolerated and generally complied with. A likely physiological rationale for HOT in CFS is related to reductions in orthostatic intolerance. An adequately powered study including strategies to enhance compliance is warranted.

Prospective evaluation of psychological distress and psychiatric morbidity in recurrent vasovagal and unexplained syncope

Syncope is experienced by a third of the population, and in the absence of cardiac pathology is most commonly of vasovagal (VVS) or unexplained origin (US). Psychiatric morbidity has been observed in up to 81% of patients with US but findings with VVS are contradictory. Little is known regarding the chronicity of their psychiatric morbidity.

OBJECTIVE

To determine the psychological profile of patients with recurrent syncope prior to and following diagnostic head-up tilt testing (HUT), and whether it predicts syncope recurrence.

METHOD

Seventy-three women and 43 men (mean age=48+/-16.6) were recruited from all consenting patients referred for HUT. Psychological status (Psychiatric Symptom Index, Anxiety Sensitivity Index (ASI), Fear of Blood Injury Subscale) and presence of mood/anxiety disorders (Primary Care Evaluation of Mental Disorders) were evaluated 1 month prior to and 6 months following HUT. Follow-up data were collected for 83 patients (mean age=48+/-17.34).

RESULTS

At baseline, clinically significant levels of distress were observed in 60% of patients. Those with US (negative HUT) had a fivefold greater risk of suffering from a depressive or anxiety disorder compared to VVS (positive HUT) after controlling for significant covariates. There was no significant change in distress level over follow-up, although psychiatric morbidity dropped from 33% to 22% (P=.049). Syncope recurrence was predicted by elevations in baseline psychological distress (OR=1.544, P=.013) independently of lifetime number of syncopes.

CONCLUSIONS

Patients exhibited high levels of psychological distress and psychiatric morbidity despite reassurance and education received after HUT. Improved screening for and treatment of psychological distress in these patients is critical.

Evaluation and Management of Syncope

Context

Syncope is a commonly encountered by primary care physicians and cardiologists. Etiology is frequently not apparent, and patients may undergo unnecessary tests. Treatment must be tailored to the likely etiology. Complexities of diagnosis and treatment often warrant referral to a specialist.

Objective

To highlight the evolving recommendations for managing syncope in a clinically and cost effective manner.

Evidence Acquisition

An electronic literature search was undertaken of the Medline database from January 1996 to April 2006, using the Medical Subject Heading syncope, defibrillators, pacemakers, echocardiogram, cardiomyopathy, long QT syndrome, Arrhythmogenic right ventricular dysplasia, and Brugada syndrome. Abstracts and titles were reviewed to identify English-language trials. Bibliographies from the references as well as scientific statements from the Heart Rhythm Society, American Heart Association, and American College of Cardiology were reviewed.

Evidence Synthesis

A methodical approach to syncope can improve diagnosis, limit testing, and identify patients at risk of fatal outcome. A thorough history, physical exam and electrocardiogram are critical to the initial diagnosis. Presence of heart disease determines the extent of work-up and treatment. A trans-thoracic echocardiogram should be performed in patients with an unclear diagnosis and a positive cardiac history or an abnormal ECG. Ventricular arrhythmias are the most common cause of syncope in patients with structural heart disease. Patients with an ejection fraction less than 30 percent should receive an implantable defibrillator with few exceptions. An electrophysiology study may assist risk stratification in syncopal patients with borderline ventricular function. In patients without structural heart disease, the presence of a well defined arrhythmia syndrome consistent with a genetically determined risk of sudden death must be sought. The 12-lead electrocardiogram, family history and clinical presentation will identify most high-risk patients. Patients without structural heart disease can often be managed conservatively with well defined strategies for preventing neurocardiogenic syncope.

Conclusions

Managing syncope requires a methodical approach. An understanding of the limitations of the diagnostic tools and treatments is important. Lethal causes of syncope make it imperative to recognize the appropriate timing of referring patients to specialists.

The role of tilt training in preventing recurrent syncope in patients with vasovagal syncope: a prospective and randomized study

BACKGROUND

Recurrent vasovagal syncope (VVS) can be a severely disabling disorder that may lead to an important deterioration of quality of life because of the severity and recurrence of episodes. This study sought to investigate the effectiveness of repeated orthostatic self-training in preventing syncope in patients with recurrent VVS.

METHODS

Eighty-two consecutive patients (mean age 41 +/- 4 years, 37 males) with recurrent VVS episodes and positive head-up tilt testing (HUT) were enrolled in this study. The patients were then randomized (1:1) to conventional therapy or conventional therapy plus additional tilt training sessions. The patients were followed for spontaneous syncope for one year. Primary end-points were the recurrence of syncope, the number of episodes, and the interval of time to the first recurrence.

RESULTS

There were no significant differences of baseline clinical characteristics and parameters of HUT between the tilt training and control groups. The patients had 4 +/- 2/year syncopal episodes prior to the HUT. The mean follow-up after randomization was 12 +/- 2 months. Spontaneous syncope recurrence during follow-up was 56% (23 patients) versus 37% (15 patients) in the control and tilt training groups, respectively (P = 0.1). Time to first recurrence was also similar in both groups (70 +/- 20 days vs 50 +/- 15 days, P = 0.09). The frequency of recurrent syncopes was similar in all types of VVSs while the rate of episodes was significantly higher in control group in patients with vasodepressor type during follow-up period (32% vs 10%, P = 0.04). The mean number of recurrent syncope episodes was also similar in both groups (3 +/- 1 vs 2 +/- 1, P = 0.4).

CONCLUSIONS

Tilt training was unable to influence the spontaneous syncope recurrence for recurrent VVS except for vasodepressor type.

Is home orthostatic self-training effective in preventing neurally mediated syncope?

BACKGROUND

Repeated orthostatic stress may prove to be of benefit in the regulation of neurally mediated syncope. But the role of home orthostatic self-training is not established to prevent symptoms in patients with neurally mediated syncope. We performed a prospective and randomized study to evaluate the effectiveness of repeated home orthostatic self-training in preventing tilt-induced neurally mediated syncope.

METHODS AND RESULTS

Fourty-two consecutive patients (24 males and 18 females, mean age 39 years, 16-68 years) with recurrent neurally mediated syncope were randomized into the tilt training and control groups. The home orthostatic self-training program consisted of daily sessions for 7 days a week for 4 weeks. In order to determine the effects of home orthostatic self-training, we repeated the head-up tilt test in both groups 4 weeks later. Among the tilt-training group, 9 of 16 patients (56%) had a positive response on follow-up head-up tilt test. Among the untreated control group, 9 of 17 patients (53%) had a positive response on follow-up head-up tilt test. In subgroup analyses according to the number of tilt-training sessions or the classified type, we found no differences in the follow-up head-up tilt test responses. Spontaneous syncope or presyncope over mean follow-up of 16.9 months were observed in 42.9% versus 47.1% in the tilt-training and control group, respectively.

CONCLUSIONS

Home orthostatic self-training was ineffective in reducing the positive response rate of head-up tilt test in patients with recurrent neurally mediated syncope.

Current management of syncope : focus on drug therapy

Syncope is defined as transient loss of consciousness as a result of inadequate cerebral perfusion. The causes of syncope fall into five broad categories: neurally mediated, orthostatic (the most frequent causes), cardiac arrhythmias, structural cardiovascular (relatively uncommon cause), and cerebrovascular (very rare). The initial evaluation of the syncope patient includes a detailed medical history and physical exam, and usually an ECG and echocardiogram. Thereafter, selected additional testing (e.g. ambulatory ECG recording, autonomic function testing, electrophysiologic study) may be needed on a case-by-case basis. Neurally mediated and orthostatic syncope should first be treated by conservative therapies including hydration/volume expanders and physical counter-maneuvers. Various drugs may play a role as second-line of treatment. However, apart from midodrine, randomized studies of drug therapy are largely lacking, and most agents have not proved to be predictably effective. For syncope due to cardiac arrhythmias, treatment options (depending on the specific circumstance) include ablation of the arrhythmia origin, antiarrhythmic drugs, and/or implantable devices (pacemakers and defibrillators). In the case of syncope due to structural cardiovascular defects (e.g. acute myocardial ischemia, pulmonary hypertension, obstructive cardiomyopathy), treatment is aimed at ameliorating the underlying structural defect. In brief, establishing a specific cause(s) for syncope is crucial. Only then can a potentially effective treatment strategy be contemplated.

Syncope and Near Syncope in Competitive Athletes

Syncope, although common among the general population, is rare among athletes. Syncope can result from any one of several causes. The majority of cases are due to neurocardiogenic syncope, without the potential for sudden death, and due to a sudden reduction in venous return. Cardiac syncope may be due to mechanical or structural factors. A thorough history and physical examination, along with an electrocardiogram, can usually distinguish benign cases from those due to more life-threatening conditions. Those at risk for sudden death need to be identified, so they can be appropriately restricted from further athletic activity.

The ACCF/AHA Scientific Statement on Syncope

The American College of Cardiology Foundation (ACCF) and the American Heart Association (AHA) have recently published, in both the Journal of the American College of Cardiology (JACC) and Circulation, a Scientific Statement on the Evaluation of Syncope ('Statement'). This Scientific Statement was commissioned to provide guidance for clinicians regarding the evaluation of patients who present with 'syncope'. The Statement was not intended to be a formal set of practice guidelines. However, in the absence of generally accepted practice guidelines in North America, the Statement's potential impact on clinical care may be more far-reaching than expected; it may erroneously be considered to be the authoritative 'de-facto' guideline document. This commentary, submitted by a multidisciplinary consortium of more than 60 physicians with expertise in the management of transient loss of consciousness (TLOC), points out that in many respects the ACCF/AHA Syncope Statement fails to address long-standing clinical errors associated with the evaluation of episodes of apparent TLOC, including syncope. If not appropriately revised, the current Statement may lead to both inadequate patient care as well as a potentially damaging legal environment for physicians undertaking evaluation of patients who present with transient loss of consciousness.