Syncope and trauma. Are syncope-related traumatic injuries the key to find the specific cause of the symptom?

Syncope is a prevalent disorder, accounting for 3–5% ofemergency department (ED) visits and 1–3% of hospitaladmissions.¹ A cardiac cause of syncope is an independent predictorof sudden death, and mortality rates are higher in patientswith cardiac syncope compared with those of non-cardiac or unknownorigin.² In addition, significant morbidity may result fromfalls or accidents resulting from syncope. Bartoletti et al.³have provided valuable information about the prevalence andthe characteristics of secondary trauma among patients referredto the ED for a transient, self-limited loss of consciousness(TLOC). A total of 1114 patients with a true syncope and 139individuals with a non-syncopal condition (including seizures,cerebrovascular accidents, dizziness, intoxication, hypoglycaemia,and psychogenic     

Early application of an implantable loop recorder allows effective specific therapy in patients with recurrent suspected neurally mediated syncope.

AIMS: This prospective multicentre observational study assessed the efficacy of specific therapy based on implantable loop recorder (ILR) diagnostic observations in patients with recurrent suspected neurally mediated syncope (NMS). METHODS AND RESULTS: Patients with three or more clinically severe syncopal episodes in the last 2 years without significant electrocardiographic and cardiac abnormalities were included. Orthostatic hypotension and carotid sinus syncope were excluded. After ILR implantation, patients were followed until the first documented syncope (Phase I). The ILR documentation of this episode determined the subsequent therapy and commenced Phase II follow-up. Among 392 patients, the 1-year recurrence rate of syncope during Phase I was 33%. One hundred and three patients had a documented episode and entered Phase II: 53 patients received specific therapy [47 a pacemaker because of asystole of a median 11.5 s duration and six anti-tachyarrhythmia therapy (catheter ablation: four, implantable defibrillator: one, anti-arrhythmic drug: one)] and the remaining 50 patients did not receive specific therapy. The 1-year recurrence rate in 53 patients assigned to a specific therapy was 10% (burden 0.07 +/- 0.2 episodes per patient/year) compared with 41% (burden 0.83 +/- 1.57 episodes per patient/year) in the patients without specific therapy (80% relative risk reduction for patients, P = 0.002, and 92% for burden, P = 0.002). The 1-year recurrence rate in patients with pacemakers was 5% (burden 0.05 +/- 0.15 episodes per patient/year). Severe trauma secondary to syncope relapse occurred in 2% and mild trauma in 4% of the patients. CONCLUSION: A strategy based on early diagnostic ILR application, with therapy delayed until documentation of syncope allows a safe, specific, and effective therapy in patients with NMS.     

The usefulness of carotid sinus massage in different patient groups

AIM: to determine the positive yield of carotid sinus massage in different patient groups: unexplained syncope, falls, dizziness and controls. DESIGN: observational study. SETTING: teaching hospital. METHODS: we studied consecutive patients over the age of 60 years referred to the 'falls clinic' with a history of unexplained syncope, unexplained falls and unexplained dizziness. We also studied asymptomatic control subjects recruited from a general practice register aged 60 years and over. All patients and control subjects underwent a full clinical assessment (comprehensive history and detailed clinical examination including supine and erect blood pressure measurements) and 12-lead electrocardiography. We performed carotid sinus massage in the supine position for 5 seconds separately on both sides followed by repeating the procedure in the upright positions using a motorised tilt table. Heart rate and blood pressure were recorded using a cardiac monitor and digital plethysmography respectively. The test was considered positive if carotid sinus massage produced asystole with more than a 3 second pause (cardioinhibitory type of carotid sinus syndrome), or a fall in systolic blood pressure of more than 50 mmHg in the absence of significant cardioinhibition (vasodepressor type of carotid sinus syndrome) or where there was evidence of both vasodepressor and cardio-inhibition as above (mixed type). RESULTS: we studied 44 asymptomatic control subjects and 221 symptomatic patients (130 with unexplained syncope, 41 with unexplained falls and 50 with unexplained dizziness). In the overall symptomatic patient group, the positive yield (any type of carotid sinus syndrome) was 17.6% (95% CI = 12.7-22.5). The positive yield in men (26.3% (95% CI = 16.4-36.2)) was twice that in women (13.1% (95% CI = 7.6-18.6)) (P = 0.014). Overall any type of carotid sinus syndrome was present in 22.3% (n = 29) of the syncope group, 17.1% (n = 7) in the unexplained fallers group and 6% (n = 3) in the dizziness group. We also found that no women with unexplained dizziness had a positive carotid sinus massage test. None of the controls demonstrated a positive response. None of the subjects suffered any complications during or after the test. CONCLUSION: the positive yield of carotid sinus massage in symptomatic patients was 17.6% with the yield in men being twice that in women. None of the asymptomatic control subjects demonstrated a positive response. The yields in unexplained syncope and unexplained falls patients were around 4-fold and 3-fold higher respectively than in unexplained dizziness patients. The positive yield in women with unexplained dizziness (without a definite history of syncope and falls) is zero. Hence, carotid sinus massage in older adults should particularly be targeted at patients with unexplained syncope and unexplained falls.     

Amnesia for loss of consciousness in carotid sinus syndrome: implications for presentation with falls

OBJECTIVES: The goal of this study was to compare the clinical characteristics of patients with carotid sinus syndrome who presented with falls with those who presented with syncope. BACKGROUND: Carotid sinus syndrome presents with both falls and syncope. The reasons for this differential presentation are unknown, but amnesia for loss of consciousness may be the underlying cause. METHODS: Two groups of 34 consecutive patients with carotid sinus syndrome as the sole cause of falls and syncope were recruited. Cognitive function and clinical characteristics were compared between the two groups. RESULTS: Syncopal subjects with carotid sinus syndrome were more likely to be older males (18 [53%] vs. 7 [21%] years; p = 0.006) with a longer duration of symptoms (27.9 vs. 13.3 months; p = 0.009) and more soft tissue injuries (19 [56%] vs. 9 [26%]; p = 0.03). Duration of asystole during carotid sinus massage was similar in both groups (5.1 vs. 5.4 s; p = 0.42), but witnessed amnesia for loss of consciousness was more frequent in fallers than those with syncope (21 [95%] vs. 4 [12%]; p < 0.001). Clinical characteristics and cognitive function were otherwise similar in both groups. CONCLUSIONS: Patients with carotid sinus syndrome have similar rates of witnessed loss of consciousness during laboratory testing regardless of symptoms. However, those presenting with falls are far less likely to perceive any disturbance of consciousness than those with syncope, showing for the first time the manner in which such patients manifest symptoms. Cognitive impairment does not explain the amnesia for loss of consciousness seen in fallers with carotid sinus syndrome.     

A standardized conventional evaluation of the mechanism of syncope in patients with bundle branch block.

BACKGROUND: The finding of bundle branch block in patients with syncope suggests that paroxysmal AV block may be the cause of syncope, even though its prevalence is unknown. METHODS: We evaluated 55 consecutive patients with syncope and bundle branch block (mean age 75 +/- 8 years; median of two syncopal episodes per patient) referred to three Syncope Units. The hierarchy and appropriateness of diagnostic tests and the definitions of the final diagnoses followed standardized predefined criteria. RESULTS: Cardiac syncope was diagnosed in 25 patients (45%): AV block in 20, sick sinus syndrome in 2, sustained ventricular tachycardia in 1, aortic stenosis in 2. Neurally mediated syncope was diagnosed in 22 (40%): carotid sinus syndrome in 5, tilt-induced syncope in 15, adenosine-sensitive syncope in 2. Syncope remained unexplained in 8 (15%). CONCLUSIONS: Less than half of the patients with bundle branch block have a final diagnosis of cardiac syncope; in these patients, paroxysmal AV block is the most frequent but not the only mechanism supposed.     

Neurally-mediated syncope.

"Neurally-mediated (reflex) syncope" refers to a reflex response that, when triggered, gives rise to vasodilation and/or bradycardia; however, the contribution of each of these two factors to systemic hypotension and cerebral hypoperfusion may differ considerably. The initial evaluation may lead to a certain diagnosis in the case of classical vasovagal syncope and of situational syncope. Classical vasovagal syncope is diagnosed if precipitating events such as fear, severe pain, emotional distress, instrumentation or prolonged standing, are associated with typical prodromal symptoms. Situational syncope is diagnosed if syncope occurs during or immediately after urination, defecation, cough or swallowing. In the absence of a certain diagnosis, absence of cardiac disease, long history of syncope, syncope after sudden unexpected unpleasant sight, sound or smell, prolonged standing at attention or crowded, warm places, nausea and vomiting, post-prandial and post-exercise state suggest a neurally-mediated cause which needs to be confirmed by specific tests. Among them, the most useful are carotid sinus massage and tilt testing. In general, education and reassurance are the sufficient initial treatment. Additional treatment may be necessary in high-risk or high-frequency settings. Treatment is not necessary in patients who have sustained a single syncope and are not having syncope in a high-risk setting. It is valuable to assess the relative contribution of cardioinhibition and vasodepression before embarking on treatment as there are different therapeutic strategies for the two aspects. Even if evidence of utility of such an assessment exists only for the carotid sinus massage, it is recommended to extend this assessment also by means of tilt testing or implantable loop recorder. Tilt training and isometric leg and arm counterpressure maneuvers are indicated in patients with recurrent vasovagal syncope. Cardiac pacing is indicated in patients with cardioinhibitory or mixed carotid sinus syndrome and in patients with cardioinhibitory vasovagal syncope with a frequency > 5 attacks per year or severe physical injury or accident and age > 40 years. The evidence fails to support the efficacy of any drug.     

The application of a standardized strategy of evaluation in patients with syncope referred to three syncope units.

BACKGROUND: The appropriate diagnostic work-up of patients with syncope is not well defined. We applied the guidelines of Italian 'Associazione Nazionale Medici Cardiologi Ospedalieri' to a group of consecutive patients with syncope referred to three Syncope Units. The aim of the study was to evaluate the applicability of those guidelines in the 'real world' and their impact on the use of the tests. METHODS: We evaluated 308 consecutive patients with syncope (mean age 61 +/- 20 years; median of three syncopal episodes per patient). The hierarchy and appropriateness of diagnostic tests and the definitions of the final diagnosis followed standardized predefined criteria. In brief, all patients underwent initial evaluation consisting of history, physical examination, supine and upright blood pressure measurement and standard electrocardiogram (ECG) (only in patients > 45 years or with history of heart disease). Any subsequent investigations were based on the findings of the initial evaluation. Priority was given to cardiological tests (prolonged ECG monitoring, exercise test, electrophysiological study), or to neurally mediated tests (carotid sinus massage, tilt test, ATP test), or to neuro-psychiatric tests, as appropriate. FINDINGS: The initial evaluation alone was diagnostic in 72 patients (23%). One further test was necessary for diagnosis in 65 patients (21%), > or = 2 tests in 64 (21%) and > or = 3 tests in 50 (16%). The diagnostic yield was 10% for ECG, 3% for echocardiogram, 16% for Holter, 5% for exercise test, 27% for electrophysiological study, 57% for carotid sinus massage, 52% for tilt testing and 15% for ATP test. At the end of the work-up the mechanism of syncope remained unexplained in 57 patients (18%). CONCLUSIONS: When standardized criteria based on the appropriateness of indications are used, few simple tests are usually needed for diagnosis of syncope.     

Lack of correlation between the responses to tilt testing and adenosine triphosphate test and the mechanism of spontaneous neurally mediated syncope.

AIMS: We prospectively correlated the results of tilt testing (TT) and adenosine triphosphate test (ATP) with the findings observed during a spontaneous syncopal relapse by means of an implantable loop recorder (ILR) in patients with a clinical diagnosis of neurally mediated syncope. METHODS AND RESULTS: We included patients with three or more clinically severe syncopal episodes in the last 2 years without significant electrocardiographic and cardiac abnormalities. Patients with orthostatic hypotension and carotid sinus syncope were excluded. After ILR implantation, patients were followed until the first documented syncope. Among 392 enrolled patients, 343 underwent TT, which was positive in 164 (48%), and 180 ATP test, which was positive in 53 (29%). Syncope was documented by ILR in 106 (26%) patients after a median of 3 months. Patients with positive and negative TT had similar baseline characteristics, syncopal recurrence rate, and mechanism of syncope, but those with positive TT had more frequently no or slight rhythm variations during spontaneous syncope (45 vs. 21%, P=0.02). An asystolic pause was more frequently found during spontaneous syncope than during TT (45 vs. 21%, P=0.02), but there was a trend for those with an asystolic response during TT also to have an asystolic response during spontaneous syncope (75 vs. 37%, P=0.1). Patients with positive ATP test responses showed syncopal recurrence rates and mechanism of syncope similar to those with negative ATP tests. CONCLUSION: In patients with neurally mediated syncope, clinical characteristics, outcome, and mechanism of syncope are poorly correlated and not predicted by the results of TT and ATP test. Therefore, these tests are of little or no value in guiding specific therapy.     

Diagnosis and characteristics of syncope in older patients referred to geriatric departments

OBJECTIVES: To test the applicability and safety of a standardized diagnostic algorithm in geriatric departments and to define the prevalence of different causes of syncope in older patients. DESIGN: Multicenter cross-sectional observational study. SETTING: In-hospital geriatric acute care departments and outpatient clinics. PARTICIPANTS: Two hundred forty-two patients (aged>or=65, mean+/-standard deviation=79+/-7, range 65-98) consecutively referred for evaluation of transient loss of consciousness to any of six clinical centers participating in the study. Of these, 11 had a syncope-like condition (5 transient ischemic attack; 6 seizures), and 231 had syncope (aged 65-74, n=71; aged>or=75, n=160). MEASUREMENTS: Protocol designed to define etiology and clinical characteristics of syncope derived from European Society of Cardiology Guidelines on syncope. RESULTS: No major complication occurred with use of the protocol. Neurally mediated was the more prevalent form of syncope in this population (66.6%). Cardiac causes accounted for 14.7% of all cases. The neuroreflex form of syncope (vasovagal, situational, and carotid sinus syndrome) was more common in younger than in older patients (62.3% vs 36.2%; P=.001), whereas orthostatic syncope was more frequent in the older than in the younger group (30.5% vs 4.2%; P<.001). In only 10.4% of cases, syncope remained of unexplained origin. After initial evaluation, a definite diagnosis was possible in 40.1% of the cases, and a suspected diagnosis was obtained in 57.9%. Syncope of suspected cardiac origin after initial evaluation was confirmed in 43.7% of cases, and neuromediated causes were confirmed in 83.5% of the cases. CONCLUSION: The protocol is applicable even beyond the age of 90 in geriatric departments. The standardized protocol is associated with a reduction in the frequency of unexplained syncope to about 10%.     

Diagnostic utility of mechanical, pharmacological and orthostatic stimulation of the carotid sinus in patients with unexplained syncope.

OBJECTIVES: The purpose of the present study was to systematically evaluate the diagnostic utility of mechanical, pharmacological and orthostatic stimulation of the carotid sinus in a consecutive series of patients with recurrent unexplained syncope. BACKGROUND: Carotid sinus hypersensitivity (CSH) is an infrequently recognized cause of recurrent unexplained syncope usually diagnosed by carotid sinus massage (CSM) in the supine position. The diagnostic utility of systematic assessment of mechanical, pharmacological and orthostatic stimulation of the carotid sinus has not been clearly established. METHODS: Eighty consecutive patients (63 +/- 12 years) with a history of recurrent unexplained syncope (mean episodes: 6 +/- 3); 30 age-matched controls (65 +/- 14 years) and 16 patients (59 +/- 12 years) with syncope not related to CSH were studied. Pharmacological stimulation of the carotid sinus was achieved by randomly administering bolus injections of nitroprusside and phenylephrine. Mechanical stimulation of the carotid sinus was performed by CSM applied for 5 s in the supine position and after 2 min at 60 degrees. A 60 degree low-dose isoproterenol head-up tilt test (HUTT) was also performed for a total duration of 30 min. RESULTS: Carotid sinus hypersensitivity was elicited by CSM in the supine position in seven (8.7%) patients, two (6.6%) controls and one (6.3%) patient with syncope unrelated to CSH, compared with 48 (60%) patients, two (6.6%) controls and one (6.3%) syncope unrelated to CSH patient after 60 degree HUTT, increasing the diagnostic yield by 51%. Baroreceptor gain was significantly reduced in the CSH group. Head-up tilt test was positive in 12 (25%) patients with CSH, two (6.6%) controls and two (12%) with documented syncope but not positive in any of the patients in which syncope remained unexplained. Diagnostic accuracy was enhanced by 38% (31% supine vs. 69% upright) when CSM was performed at 60 degrees. CONCLUSIONS: CSH was documented in 68% of patients, 8.7% in the supine position and 60% in the upright position. Sensitivity was increased by 51%, and diagnostic accuracy was enhanced by 38% by performing CSM in the upright position. Decreased baroreceptor gain was documented and may play a role in the pathophysiology of CSH.     

Diagnosis of carotid sinus hypersensitivity in older adults: carotid sinus massage in the upright position is essential

OBJECTIVE—To assess the diagnostic value of supine and upright carotid sinus massage in elderly patients.
DESIGN—Prospective controlled cohort study.
SETTING—Three inner city accident and emergency departments and a dedicated syncope facility.
PATIENTS—1375 consecutive patients aged > 55 years presenting with unexplained syncope and drop attacks; 25 healthy controls.
INTERVENTIONS—Bilateral supine carotid sinus massage, repeated in the 70° head up tilt position if the initial supine test was not diagnostic of cardioinhibitory and mixed carotid sinus hypersensitivity.
MAIN OUTCOME MEASURES—Diagnosis of cardioinhibitory or mixed carotid sinus hypersensitivity; clinical characteristics of supine v upright positive groups.
RESULTS—226 patients were excluded for contraindications to carotid sinus massage. Of 1149 patients undergoing massage, 223 (19%) had cardioinhibitory or mixed carotid sinus hypersensitivity; 70 (31%) of these had a positive response to massage with head up tilt following negative supine massage (95% confidence interval, 25.3% to 37.5%). None of the healthy controls showed carotid sinus hypersensitivity on erect or supine massage. The initially positive supine test had 74% specificity and 100% sensitivity; these were both 100% for the upright positive test. The clinical characteristics of the supine v upright positive subgroups were similar.
CONCLUSIONS—The diagnosis of carotid sinus hypersensitivity amenable to treatment by pacing may be missed in one third of cases if only supine massage is performed. Massage should be done routinely in the head up tilt position if the initial supine test is negative.


Keywords: carotid sinus; tilt table testing; syncope; elderly patients     

Clinical spectrum of neurally mediated reflex syncopes.

AIMS: The clinical features of the various types of neurally mediated reflex syncope have not been systematically investigated and compared. We sought to assess and compare the clinical spectrum of neurally mediated reflex syncopes. METHODS AND RESULTS: Four hundred sixty-one patients with syncope were prospectively evaluated and 280 had neurally mediated reflex syncope. Each patient was interviewed using a standard questionnaire. A cause of syncope was assigned using standardized diagnostic criteria. Typical vasovagal syncope was diagnosed in 39 patients, situational syncope in 34, carotid sinus syncope in 34, tilt-induced syncope in 142 and complex neurally mediated syncope (positive response to both carotid sinus massage and tilt test) in 31. The clinical features of situational, carotid sinus, tilt-induced and complex neurally mediated syncope were very similar. By contrast, typical vasovagal syncope differed from other neurally mediated syncopes not only in terms of its precipitating factors (fear, strong emotion, etc.), which constituted predefined diagnostic criteria, but also in the variety of its clinical features (lower age and prevalence of organic heart disease, higher prevalence of prodromal symptoms, and of autonomic prodromes, longer duration of prodromes, higher prevalence of symptoms during the recovery phase and lower prevalence of trauma). CONCLUSION: The clinical spectrum of neurally mediated reflex syncopes demonstrates much overlap between them. However, when the afferent neural signals are localized in cortical sites, as in typical vasovagal syncope, symptoms are more frequent and of longer duration.     

Management of syncope referred urgently to general hospitals with and without syncope units.

OBJECTIVE: We tested the hypothesis that management of patients with syncope admitted urgently to a general hospital may be influenced by the presence of an in-hospital structured syncope unit. BACKGROUND: The management of syncope is not standardized.Methods We compared six hospitals equipped with a syncope unit organized inside the department of cardiology with six matched hospitals without such facilities. The study enroled all consecutive patients referred to the emergency room from 5 November 2001 to 7 December 2001 who were affected by transient loss of consciousness as their principal symptom. RESULTS: There were 279 patients in the syncope unit hospitals and 274 in the control hospitals. In the study group, 30 (11%) patients were referred to the syncope unit for evaluation. In the study group, 12% fewer patients were hospitalized (43 vs 49%, not significant) and 8% fewer tests were performed (3.3+/-2.2 vs 3.6+/-2.2 per patient, not significant). In particular, the study group patients underwent fewer basic laboratory tests (75 vs 86%, P=0.002), fewer brain-imaging examinations (17 vs 24%, P=0.05), fewer echocardiograms (11 vs 16%, P=0.04), more carotid sinus massage (13 vs 8%, P=0.03) and more tilt testing (8 vs 1%, P=0.000). In the study group, there was a +56% rate of final diagnosis of neurally mediated syncope (56 vs 36%, P=0.000). CONCLUSION: Although only a minority of patients admitted as an emergency are referred to the syncope unit, overall management is substantially affected. It is speculated that the use of a standardized approach, such as that typically adopted in the syncope unit, is able to influence overall practice in the hospital.     

Prevalence of positive carotid sinus massage and related risk of syncope in patients with Alzheimer's disease.

AIMS: The prevalence of positive carotid sinus massage (CSM) in asymptomatic elderly persons and related risk of syncope are poorly known. METHODS AND RESULTS: We examined the ability of CSM to predict the risk of profound bradycardia or syncope in 30 patients with Alzheimer's disease (AD) and no history of syncope, before treatment with cholinesterase inhibitors. Carotid sinus massage was repeated at 1, 2 and 8 months after onset of cholinergic therapy. The long-term incidence of syncope was observed over a 20-month follow-up. Among the study patients (mean age = 80 +/- 6 years, 83% women), 10 had positive CSM, with prolonged ventricular standstill in two of them (6.7%). The response to CSM was not predictive of an increased risk in bradycardia-mediated syncope, though syncope occurred in three patients during long-term follow-up, related to orthostatic hypotension in one and to undetermined causes in the others. Cholinergic therapy in all patients, or drugs that slow cardiac conduction, administered to 40% of the responders to CSM and 45% of the non-responders, or the presence of a bundle branch block did not affect the response to CSM or incidence of syncope. CONCLUSIONS: A positive CSM was (i) observed in 30% of elderly persons with AD and no history of syncope, and (ii) not predictive of an increased risk of bradycardia-mediated syncope.     

Cardioinhibitory carotid sinus hypersensitivity predicts an asystolic mechanism of spontaneous neurally mediated syncope.

AIMS: We correlated the finding of cardioinhibitory carotid sinus hypersensitivity (CSH) with that observed during a spontaneous syncopal relapse by means of an implantable loop recorder (ILR). METHODS AND RESULTS: We included 18 consecutive patients with suspected recurrent neurally mediated syncope and positive cardioinhibitory response during carotid sinus massage (max pause 5.5 +/- 1.6 s) who had subsequent documentation of a spontaneous syncope by means of an ILR. They were compared with a 2:1 age- and sex-matched group of 36 patients with a clinical diagnosis of recurrent neurally mediated syncope and negative response to carotid sinus massage, tilt testing and ATP test. Asystole >3 s was observed at the time of the spontaneous syncope in 16 (89%) of CSH patients and in 18 (50%) of the control group (P = 0.007). Sinus arrest was the most frequent finding among CSH patients but not among controls (72 vs. 28%, P = 0.003). After ILR documentation, 14 CSH patients with asystole received dual-chamber pacemaker implantation; during 35 +/- 22 months of follow-up, 2 syncopal episodes recurred in 2 patients (14%), and pre-syncope occurred in another 2 patients (14%). Syncope burden decreased from 1.68 (95% confidence interval 1.66 - 1.70) episodes per patient per year before to 0.04 (0.038-0.042) after pacemaker implant (98% relative risk reduction). CONCLUSIONS: In patients with suspected neurally mediated syncope, the finding of cardioinhibitory CSH predicts an asystolic mechanism at the time of spontaneous syncope and, consequently, suggests a possible benefit of cardiac pacing therapy.     

Carotid sinus hypersensitivity in asymptomatic older persons: implications for diagnosis of syncope and falls

BACKGROUND: Carotid sinus hypersensitivity is the most commonly reported cause of falls and syncope in older persons. Recent guidelines recommend 5 to 10 seconds of carotid sinus massage in supine and upright positions with beat-to-beat monitoring. The aim of this study was to determine the prevalence of carotid sinus hypersensitivity in (1) an unselected community sample of older people and (2) a subsample with no history of syncope, dizziness, or falls using recently standardized diagnostic criteria. METHODS: One thousand individuals older than 65 years were randomly sampled from a single general practice register; 272 participants underwent supine and upright carotid sinus massage with continuous heart rate and phasic blood pressure monitoring. Carotid sinus hypersensitivity was defined as asystole of 3 seconds or greater and/or a drop in systolic blood pressure of 50 mm Hg or greater. RESULTS: Carotid sinus hypersensitivity was present in 107 individuals (39%); 24% had asystole of 3 seconds or greater during carotid sinus massage; and 16% had symptoms (including syncope) with carotid sinus hypersensitivity. Age (odds ratio, 1.05; 95% confidence interval, 1.00-1.09) and male sex (odds ratio, 1.71; 95% confidence intervals, 1.04-2.82) were the only predictors of carotid sinus hypersensitivity. In 80 previously asymptomatic individuals, carotid sinus hypersensitivity was present in 28 (35%) and accompanied by symptoms in 10. The 95th percentile for carotid sinus massage response was 7.3 seconds' asystole and a 77-mm Hg drop in systolic blood pressure. CONCLUSIONS: Carotid sinus hypersensitivity is common in older persons, even those with no history of syncope, dizziness, or falls. The finding of a hypersensitive response should not necessarily preclude further investigation for other causes of syncope.     

Complications of carotid sinus massage--a prospective series of older patients

BACKGROUND: there is a causal association between carotid sinus hypersensitivity, falls and syncope in elderly subjects. Neurological complications during carotid sinus massage have been reported in case studies and two retrospective series. Our aim was prospectively to ascertain the incidence of complications occurring after carotid sinus massage performed for diagnostic purposes in a consecutive series of patients. METHODS: 1000 consecutive subjects aged 50 years or over who attended the accident and emergency department with syncope or 'unexplained' falls had carotid sinus massage. Carotid sinus massage was performed for 5 s on the right and then left sides both supine and upright (70 degrees head-up tilt) with continuous heart rate and phasic blood pressure recording. Contraindications to carotid sinus massage were the presence of a carotid bruit, recent history of stroke or myocardial infarction or previous ventricular tachyarrhythmia. RESULTS: complications occurred in nine patients immediately after cessation of carotid sinus massage. Eight had transient neurological complications possibly attributable to carotid sinus massage: visual disturbance, 'pins and needles' and sensation of finger numbness in two cases each, leg weakness in one and sensation of 'being drunk' in one. All transient complications resolved within 24 h. In one patient mild weakness of the right hand persisted. CONCLUSIONS: no subjects had cardiac complications and 1% had possible neurological symptoms, which resolved in most cases. Persistent neurological complications are uncommon, occurring in 1:1000 patients (0.1%) or 1: 3805 episodes of carotid sinus massage (0.03%).     

Carotid sinus syndrome--clinical characteristics in elderly patients.

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

Symptomatic "isolated" carotid sinus hypersensitivity: natural history and results of treatment with anticholinergic drugs or pacemaker

Because syncope may occur intermittently in patients with carotid sinus hypersensitivity, a knowledge of its natural history is needed as a basis for interpreting the usefulness of therapy. Fifty-six consecutive patients are described (47 men and 9 women; mean age 61 years) with carotid sinus hypersensitivity and syncope in whom 24 hour ambulatory monitoring and intracardiac electrophysiologic study revealed no other cause for the syncope. The mean duration of symptoms was 44 months (range 1 to 480) and the mean number of episodes was 4.0 (range 1 to 20). During a follow-up period of 6 to 120 months (median 40), syncope recurred in 3 of 13 patients who received no treatment, in 2 of 23 patients who received a pacemaker and in 4 of 20 patients who received anticholinergic drugs (incidences corrected for totals available at follow-up: 27, 9 and 22%, respectively). Two-thirds of the patients receiving no treatment were asymptomatic compared with all nine of the patients with syncope and a pure cardioinhibitory response to carotid sinus massage who received an atrioventricular (AV) sequential pacemaker. Although pacing was effective in abolishing syncope, its use should be reserved for recurrent episodes because of the high rate of spontaneous remission of symptoms.     

Permanent cardiac pacing in vasovagal syncope and carotid sinus syndrome

Vasovagal syncope and carotid sinus syndrome are common conditions in young and elderly people, respectively, mostly with benign prognosis. Nevertheless, severe or "malignant" syncopal attacks in some patients may be associated with life-threatening injury. Unfortunately, up to now almost all drug trials have failed to demonstrate any benefit in preventing syncope and interventional approach (pacemaker) may be appropriate. This article contains literature review and discussion of indications for pacing in vasovagal syncope and carotid sinus syndrome.