Risk factors for syncope in a community-based sample (the Framingham Heart Study)

Bradycardia risk stratification with implantable loop recorder after unexplained syncope

BACKGROUND

An implantable loop recorder is an effective tool for diagnosing unexplained syncope. However, after a first episode in non-high-risk patients, the usefulness of implantable loop recorder implantation remains unclear.

AIMS

To analyse relevant risk factors for significant bradycardia in order to identify patients who do or do not benefit from implantable loop recorder implantation. Also, to study whether implantable loop recorder implantation with remote monitoring is associated with less recurrence of traumatic syncope.

METHODS

This was a retrospective monocentric study including patients with implantable loop recorder implantation after unexplained syncope, using remote monitoring and iterative consultations.

RESULTS

Two hundred and thirty-seven patients were implanted for unexplained syncope. Significant bradycardia occurred in 53 patients (22.4%): 23 (43.4%) caused by paroxysmal atrioventricular block and 30 (56.6%) caused by sinus node dysfunction, leading to permanent pacemaker implantation in 48 patients. Compared with younger patients, there was a 3.46-fold increase (95% confidence interval 1.92-6.23; P<0.0001) in the risk of significant bradycardia in patients aged≥60 years. Based on multivariable analysis, only "typical syncope" was associated with significant bradycardia occurrence (hazard ratio 3.14, 95% confidence interval 1.75-5.65; P=0.0001). There was no recurrence of significant bradycardia with traumatic complications among patients implanted for traumatic syncope.

CONCLUSIONS

This study shows that: (1) implantable loop recorders identify more significant bradycardia in patients aged≥60 presenting with a first non-high-risk typical syncope, suggesting that an implantable loop recorder should be implanted after a first episode of unexplained syncope in such conditions; and (2) after traumatic syncope, implantable loop recorder implantation is safe, and is associated with little or no recurrence of traumatic syncope.

New-onset syncope in diabetic patients treated with sodium-glucose cotransporter-2 inhibitors versus dipeptidyl peptidase-4 inhibitors: a Chinese population-based cohort study

BACKGROUND AND AIMS

Syncope is a symptom that poses an important diagnostic and therapeutic challenge, and generates significant cost for the healthcare system. Sodium-glucose cotransporter-2 inhibitors (SGLT2i) have demonstrated beneficial cardiovascular effects, but their possible effects on incident syncope have not been fully investigated. This study compared the effects of SGLT2i and dipeptidyl peptidase-4 inhibitors (DPP4i) on new-onset syncope.

METHODS AND RESULTS

This was a retrospective, territory-wide cohort study enrolling type 2 diabetes mellitus (T2DM) patients treated with SGLT2i or DPP4i between 1 January 2015 and 31 December 2020, in Hong Kong, China. The outcomes were hospitalization of new-onset syncope, cardiovascular mortality, and all-cause mortality. Multivariable Cox regression and different approaches using the propensity score were applied to evaluate the association between SGLT2i and DPP4i with incident syncope and mortality. After matching, a total of 37 502 patients with T2DM were included (18 751 SGLT2i users vs. 18 751 DPP4i users). During a median follow-up of 5.56 years, 907 patients were hospitalized for new-onset syncope (2.41%), and 2346 patients died from any cause (6.26%), among which 471 deaths (1.26%) were associated with cardiovascular causes. Compared with DPP4i users, SGLT2i therapy was associated with a 51% lower risk of new-onset syncope [HR 0.49; 95% confidence interval (CI) 0.41-0.57; P < 0.001], 65% lower risk of cardiovascular mortality (HR 0.35; 95% CI 0.26-0.46; P < 0.001), and a 70% lower risk of all-cause mortality (HR 0.30; 95% CI 0.26-0.34; P < 0.001) in the fully adjusted model. Similar associations with syncope were observed for dapagliflozin (HR 0.70; 95% CI 0.58-0.85; P < 0.001), canagliflozin (HR 0.48; 95% CI 0.36-0.63; P < 0.001), and ertugliflozin (HR 0.45; 95% CI 0.30-0.68; P < 0.001), but were attenuated for empagliflozin (HR 0.79; 95% CI 0.59-1.05; P = 0.100) after adjusting for potential confounders. The subgroup analyses suggested that, compared with DPP4i, SGLT2i was associated with a significantly decreased risk of incident syncope among T2DM patients, regardless of gender, age, glucose control status, Charlson comorbidity index, and the association remained constant amongst those with common cardiovascular drugs and most antidiabetic drugs at baseline.

CONCLUSION

Compared with DPP4i, SGLT2i was associated with a significantly lower risk of new-onset syncope in patients with T2DM, regardless of gender, age, degree of glycaemic control, and comorbidity burden.

Correlation between percutaneous patent foramen ovale closure and recurrence of unexplained syncope

Background

The relationship between patent foramen ovale (PFO) and unexplained syncope remains to be illustrated. Therefore, this study aimed to explore the outcomes and prognostic factors for syncope recurrence after PFO closure.

Methods

Patients with both large right-to-left shunting (RLS) PFO and unexplained syncope who visited the cardiovascular department of Xiangya Hospital Central South University from 1 January 2017 to 31 December 2021 were consecutively enrolled in our study. The recurrence rate of syncope was compared between the non-closure group (n = 20) and the closure group (n = 91).

Results

A total of 111 patients were finally included. After 31.11 ± 14.30 months of follow-up, only 11% of patients in the closure group had recurrent syncope, which was much lower than that of the non-closure group (11.0 vs. 35%, P = 0.018). We further investigated the possible prognostic factors for syncope recurrence in the closure group and found syncope occurring more than five times preoperatively, hypertension, and residual RLS at 12-month follow-up were significantly correlated with a higher number of recurrences.

Conclusions

PFO closure reduced the recurrence rate of unexplained syncope. The efficacy of prevention was prognosticated by factors including the presence or absence of syncope induction, the frequency of syncope episodes, and the presence or absence of hypertension. Syncope recurrence was also related to residual shunts post closure.

Patient characteristics and diagnostic tests associated with syncopal falls: A Southwestern surgical congress multicenter study

BACKGROUND

Patients suspected of syncope frequently undergo laboratory and imaging studies to determine the etiology of the syncope. Variability exists in these workups across institutions. The purpose of this study was to evaluate the utilization and diagnostic yield of these workups and the patient characteristics associated with syncopal falls.

METHODS

A multi-institutional retrospective review was performed on adult patients admitted after a fall between 1/2017-12/2018. Syncopal falls were compared to non-syncopal falls.

RESULTS

4478 patients were included. There were 795 (18%) patients with a syncopal fall. Electrocardiogram, troponin, echocardiogram, CT angiography (CTA), and carotid ultrasound were more frequently tested in syncope patients compared to non-syncope patients. Syncope patients had higher rates of positive telemetry/Holter monitoring, CTAs, and electroencephalograms.

CONCLUSION

Patients who sustain syncopal falls frequently undergo diagnostic testing without a higher yield to determine the etiology of syncope.

Atrial Fibrillation Is Associated With Syncope and Falls in Older Adults: A Systematic Review and Meta-analysis

OBJECTIVE

To examine the potential association of atrial fibrillation (AF) to syncope and falls, we undertook a systematic review and meta-analysis given the increasing prevalence of AF in older adults as well as emerging data that it is a risk factor for dementia.

PATIENTS AND METHODS

CENTRAL, PubMed, and EMBASE databases were searched from inception to January 31, 2019, to retrieve relevant studies. Search terms consisted of MeSH, tree headings, and keywords relating patients with "AF," "falls," "syncope," and "postural hypotension." When possible; results were pooled using a random-effects model.

RESULTS

A total of 10 studies were included, with 7 studies (36,444 patients; mean ± SD age, 72±10 years) reporting an association between AF and falls and 3 studies (6769 patients; mean ± SD age, 65±3 years) reporting an association between AF and syncope. Pooled analyses demonstrate that AF is independently associated with falls (odds ratio, 1.19; 95% CI, 1.07-1.33; P=.001) and syncope (odds ratio, 1.88; 95% CI, 1.20-2.94; P=.006). There was overall moderate bias and low-moderate heterogeneity (I²=37%; P=.11) for falls and moderate bias with low statistical heterogeneity (I²=0%; P=.44) for syncope. Persistent AF, but not paroxysmal AF, was associated with orthostatic intolerance in 1 study (4408 patients; mean ± SD age, 66±6 years).

CONCLUSION

AF is independently associated with syncope and falls in older adults. Further studies are needed to delineate mechanistic links and to guide management to improve outcomes in these patients.

TRIAL REGISTRATION

PROSPERO: trial identifier: CRD4201810721.

Usefulness of an Implantable Loop Recorder in Diagnosing Unexplained Syncope and Predictors for Pacemaker Implantation

BACKGROUND

An implantable loop recorder (ILR) is an effective tool for diagnosing unexplained syncope (US). We examined the diagnostic utility of an ILR in detecting arrhythmic causes of US and determining which clinical factors are associated with pacemaker (PM) implantation.

METHODS

This retrospective, multicenter, observational study was conducted from February 2006 to April 2018 at 11 hospitals in Korea. Eligible patients with recurrent US received an ILR to diagnose recurrent syncope and document arrhythmia.

RESULTS

A total of 173 US patients (mean age, 67.6 ± 16.5 years; 107 men [61.8%]) who received an ILR after a negative conventional workup were enrolled. During a mean follow-up of 9.4 ± 11.1 months, 52 patients (30.1%) had recurrent syncope, and syncope-correlated arrhythmia was confirmed in 34 patients (19.7%). The ILR analysis showed sinus node dysfunction in 24 patients (70.6%), supraventricular tachyarrhythmia in 4 (11.8%), ventricular arrhythmia in 4 (11.8%), and sudden atrioventricular block in 2 (5.9%). Overall, ILR detected significant arrhythmia in 99 patients (57.2%) irrespective of syncope. Among patients with clinically relevant arrhythmia detected by ILR, PM implantation was performed in 60 (34.7%), an intra-cardiac defibrillator in 5 (2.9%), and catheter ablation in 4 (2.3%). In a Cox regression analysis, history of paroxysmal atrial fibrillation (PAF) (hazard ratio [HR], 2.34; 95% confidence interval [CI], 1.33-4.12; P < 0.01) and any bundle branch block (BBB) (HR, 2.52; 95% CI, 1.09-5.85; P = 0.03) were significantly associated with PM implantation.

CONCLUSION

ILR is useful for detecting syncope-correlated arrhythmia in patients with US. The risk of PM is high in US patients with a history of PAF and any BBB.

Electrocardiogram and cardiac testing among patients in the emergency department with seizure versus syncope

Objective

Cardiogenic syncope can present as a seizure. The distinction between seizure disorder and cardiogenic syncope can only be made if one considers the diagnosis. Our main objective was to identify whether patients presenting with a chief complaint (reason for visit) as seizure or syncope received an electrocardiogram in the emergency department across all age groups.

Methods

We conducted a secondary analysis of data collected in the 2010 to 2014 National Hospital Ambulatory Medical Care Survey comparing patients presenting with a chief complaint of syncope versus seizure to determine likelihood of getting an evaluation for possible life threatening cardiovascular disease. The primary endpoint was receiving an electrocardiogram in the emergency department; secondary endpoint was receiving cardiac biomarkers.

Results

There was a total of 144,094 patient encounters. Of these visits, 1,553 had syncope and 1,470 had seizure (60.3% vs. 44.2% female, 19.9% vs. 29.0% non-white). After adjusting for age, sex, mode of arrival and insurance, patients with syncope were more likely to receive an electrocardiogram compared to patients with seizure (odds ratio, 10.86; 95% confidence interval [CI], 8.52 to 13.84). This was true across all age groups (0 to 18 years, 56% vs. 7.5%; 18 to 44 years, 60% vs. 27%; 45 to 64 years, 82% vs. 41%; ≥65 years, 85% vs. 68%; P<0.01 for all). Car- diac biomarkers were also obtained more frequently in adult patients with syncope patients (18 to 44 years, 17.5% vs. 10.5%; 45 to 64 years, 33.8% vs. 21.4%; ≥65 years, 47.1% vs. 32.3%; P<0.01 for all).

Conclusion

Patients evaluated in the emergency department for syncope received an electrocar- diogram and cardiac biomarkers more frequently than those that had seizure.

Syncope, Hypotension, and Falls in the Treatment of Hypertension: Results from the Randomized Clinical Systolic Blood Pressure Intervention Trial

OBJECTIVE

To determine predictors of serious adverse events (SAEs) involving syncope, hypotension, and falls, with particular attention to age, in the Systolic Blood Pressure Intervention Trial.

DESIGN

Randomized clinical trial.

SETTING

Academic and private practices across the United States (N = 102).

PARTICIPANTS

Adults aged 50 and older with a systolic blood pressure (SBP) of 130 to 180 mmHg at high risk of cardiovascular disease events, but without diabetes, history of stroke, symptomatic heart failure or ejection fraction less than 35%, dementia, or standing SBP less than 110 mmHg (N = 9,361).

INTERVENTION

Treatment of SBP to a goal of less than 120 mmHg or 140 mmHg.

MEASUREMENTS

Outcomes were SAEs involving syncope, hypotension, and falls. Predictors were treatment assignment, demographic characteristics, comorbidities, baseline measurements, and baseline use of cardiovascular medications.

RESULTS

One hundred seventy-two (1.8%) participants had SAEs involving syncope, 155 (1.6%) hypotension, and 203 (2.2%) falls. Randomization to intensive SBP control was associated with greater risk of an SAE involving hypotension (hazard ratio (HR) = 1.67, 95% confidence interval (CI) = 1.21-2.32, P = .002), and possibly syncope (HR = 1.32, 95% CI = 0.98-1.79, P = .07), but not falls (HR = 0.98, 95% CI = 0.75-1.29, P = .90). Risk of all three outcomes was higher for participants with chronic kidney disease or frailty. Older age was also associated with greater risk of syncope, hypotension, and falls, but there was no age-by-treatment interaction for any of the SAE outcomes.

CONCLUSIONS

Participants randomized to intensive SBP control had greater risk of hypotension and possibly syncope, but not falls. The greater risk of developing these events associated with intensive treatment did not vary according to age.

Predictors of future arrhythmic events in patients with unexplained syncope

AIMS

The purpose of this study was to examine the usefulness of implantable loop recorders (ILRs) for symptom-rhythm correlation and to identify predictors of future arrhythmic events.

PATIENTS AND METHODS

In our dual-centre study, we analysed ILR data of 189 patients (mean age 67.4 ± 15.2 years, 114 male) with unexplained syncope (single syncope 21 patients, recurrent 168 patients, traumatic injury 43 patients). Patients had severe comorbidities such as hypertension (n = 127), coronary artery disease (n = 31), diabetes mellitus (n = 33) and chronic renal insufficiency (n = 18). The median ILR usage was 29 months (M), with a range between 1 and 46 M.

RESULTS

Forty-nine (26%) patients experienced syncope during the study, with a median of 8 M to first recurrence of syncope. In 43 patients, pacemaker implantation was performed because of sinus node disease (n = 29), high-degree AV-block (n = 6) or atrial fibrillation with slow ventricular rate (n = 8). In five patients, an ICD was implanted because of documented ventricular tachycardia (n = 4) or left ventricular ejection fraction <35% (n = 1). One patient received ablation of the cavotricuspid isthmus because of documented atrial flutter. Concerning the clinical course, in five patients explantation of the ILR was necessary due to pocket infection. Three patients died due to non-cardiac causes. Logistic regression analysis revealed that older patients had a significantly higher risk for future arrhythmic events (OR 1.3, p = .039).

CONCLUSIONS

ILR monitoring is effective in indicating causes of unexplained syncope by providing symptom-rhythm associations. Only age was a predictor of future arrhythmic events. The mortality in patients with unexplained syncope was very low.

The Evaluation of Syncope in a Predominantly Black Population: Focus on Neuroimaging

Background:

Current guidelines do not support the routine use of computed tomography (CT) scan of the head in the diagnostic workup of syncope. There is a lack of research to support whether these guidelines apply to the Black population.

Aims:

This study aims to evaluate the yield of neuroimaging in the evaluation of Syncope in a predominantly Black patient population and to test whether current guidelines based on studies conducted in other populations hold true in this group.

Material and Methods:

A retrospective review of records of 151 patients admitted to a University Hospital with Syncope from 2011 to 2014 was performed. Data collected include CT head, magnetic resonance imaging of the brain, magnetic resonance angiogram, electroencephalogram, and orthostatic vital signs. Demographic data, admitting service, and comorbid conditions were identified. Syncope was classified as cardiogenic, orthostatic, vasovagal, situational, or undetermined. Statistical analysis was performed to determine which diagnostic tools were useful in identifying the potential causes of syncope. Data analysis was conducted using the Statistical Analysis System software 9.3 (SAS Institute, Cary, NC) and Statistical Analysis and Graphics (NCSS 9.0.7, Kaysville, UT).

Results:

One hundred and twenty eight (84.8%) of the patients were Black. The average age was 56.62 ± 18.78 standard deviation and 68.2% (103) were female. One hundred and fourteen patients (75.5%) had a CT brain. Five out of 114 patients had an acute abnormality on CT (4.4%). Only 1 of these 5 patients had an abnormality that was related to syncope. CT brain (P = 0.978) was not found to be predictive of underlying etiology of syncope despite high frequency of use.

Conclusions:

CT head was not useful in determining the etiology of syncope in a predominantly Black population. Current guidelines and studies conducted in other populations have detected similar findings.

National Veterans Health Administration Hospitalizations for Syncope Compared to Acute Myocardial Infarction, Fracture, or Pneumonia in Community-Dwelling Elders: Outpatient Medication and Comorbidity Profiles

The authors used 2 national Veterans Health Administration databases to identify outpatient medications and all 30 Elixhauser comorbidities for 2579 unique patients, age 65+ years, hospitalized for syncope in fiscal year 2004. For comparison, we identified other elderly patients hospitalized with acute myocardial infarction (N = 4491), fracture (N = 2797), or pneumonia (N = 9473). The categories of medications included drugs that affect the cardiovascular, central nervous, or the muscular skeletal system. The most notable differences between syncope compared to acute myocardial infarction patients occurred in central nervous system drugs in anticonvulsants/barbiturates, antidepressants, antihistamine/antinauseants, antipsychotics, and cholinesterase inhibitors (P < .0018). Comparing syncope patients with fracture patients, the central nervous medication profile was similar, but the cardiovascular medication profile differed (P < .0018); their hypertension comorbidities also differed (60.45% vs 46.34%); (P < .0016). These findings indicate significant potential associations that warrant further study. Studies linking national outpatient medications to hospitalizations for specific conditions can foster the development of more proactive pharmacovigilance systems.

Syncope and near-syncope as a multifactorial problem in geriatric inpatients: Systemic hypotension is an underrated predictor for syncope exclusively

PURPOSE

Syncope (SC) and near-syncope (NS) are still misunderstood syndromes. Aim of study was to determine the risk factors for SC, NS, as well as for both entities (SC/NS) in geriatric inpatients reporting these events within the last year, irrespectively of the reason of admission to hospital.

MATERIAL AND METHODS

The retrospective study covered 250 patients, consecutively admitted to the geriatric ward. Patients were assigned to the three models: SC and/or NS in total, n=106; isolated NS, n=72; SC with co-existing NS, if any, n=34, and compared with patients without any such events (n=144). The patients underwent a comprehensive geriatric assessment and complete clinical investigation. The binary logistic regression was applied to predict risk factors for each of the models.

RESULTS

Falls were most predictive for NS model (OR 35.4; 95% CI 10.3-121.1), and systemic hypotension for SC model (OR 92.9; 95% CI 6.1-1421.0). The highest specificity (85%) and sensitivity (81%) were found for the SC/NS model, with the highest contribution by falls (OR 18.1; 95% CI, 7.6-45.2), orthostatic hypotension (OR 8.1; 95% CI, 3.5-18.5), a history of stroke or transient ischemic attack, treatment with an angiotensin receptor blocker, plasma creatinine >1.4mg/dL, negatively self-rated health, vertigo, pathology of carotid arteries, and lack of hypertension.

CONCLUSIONS

Syncope and near-syncope in geriatric inpatients have multifactorial and cumulative aetiology, with blurred, frequently overlapping boundaries between them. The falls, postural hypotension, and/or brain hypoperfusion of different origin seem to be most predictive of the both events, however low systemic blood pressure was predictive for the syncope exclusively.

Cardiovascular safety profile of dapoxetine during the premarketing evaluation

The cardiovascular safety profile of dapoxetine, a novel selective serotonin reuptake inhibitor (SSRI) developed as an on-demand oral treatment for premature ejaculation (PE) in men, is evaluated. The cardiovascular assessment of dapoxetine was conducted throughout all stages of drug development, with findings from preclinical safety pharmacology studies, phase I clinical pharmacology studies investigating the effect of dapoxetine on QT/corrected QT (QTc) intervals in healthy men, and phase III, randomized, placebo-controlled studies evaluating the safety (and efficacy) of the drug. Preclinical safety pharmacology studies did not suggest an adverse electrophysiologic or hemodynamic effect with concentrations of dapoxetine up to 2-fold greater than recommended doses. Phase I clinical pharmacology studies demonstrated that dapoxetine did not prolong the QT/QTc interval and had neither clinically significant electrocardiographic effects nor evidence of delayed repolarization or conduction effects, with dosing up to 4-fold greater than the maximum recommended dosage. Phase III clinical studies of dapoxetine in men with PE indicated that dapoxetine was generally safe and well tolerated with the dosing regimens used (30mg and 60mg as required). Events of syncope were reported during the clinical development program, with the majority occurring during study visits (on site) on day 1 following administration of the first dose when various procedures (e.g. orthostatic maneuvers, venipunctures) were performed, suggesting that the procedures contributed to the incidence of syncope. This was consistent with previous reports showing that these and similar factors contribute to or trigger vasovagal syncope. Findings of the dapoxetine development program demonstrate that dapoxetine is associated with vasovagal-mediated (neurocardiogenic) syncope. No other associated significant cardiovascular adverse events were identified.

Short-term aerobic exercise reduces nitroglycerin-induced orthostatic intolerance in older adults with type 2 diabetes

AIMS/HYPOTHESIS

Older adults are at a high risk for syncope due to orthostatic intolerance (OI), and this risk increases with comorbid type 2 diabetes and vasoactive medications. Despite many benefits, previous investigations have shown worsening OI with aerobic training. We examined whether aerobic exercise reduced OI in older adults with type 2 diabetes who were given a short-acting vasoactive agent (nitroglycerin).

METHODS

Forty older adults (25 males and 15 females, mean age 71.4 ± 0.7 years, ranging in age from 65 to 83 years) with type 2 diabetes were recruited. Subjects were randomized to each of 2 groups: an aerobic group (3 months of vigorous aerobic exercise) and a nonaerobic (no aerobic exercise) group. Exercise sessions were supervised by a certified exercise trainer 3 times per week. After being given 400 μg of sublingual nitroglycerin, each subject was placed in a 70° head-up tilt for 30 minutes.

RESULTS

When the 2 groups were compared using a Cox proportional hazards model, tilt table tolerance was significantly better in the aerobic group as compared to in the nonaerobic group (χ(2)(MC) = 7.271, P = 0.007).

CONCLUSIONS

Our findings indicate that a relatively short aerobic exercise intervention can improve postnitroglycerin orthostatic tolerance in older adults with type 2 diabetes.

Predicting recurrence of vasovagal syncope: a simple risk score for the clinical routine

BACKGROUND

Predictors for recurrence of syncope are lacking in patients with vasovagal syncope. The aim of this study was to identify risk factors for recurrence of syncope and develop a simple prognostic risk score of clinical value.

METHODS

Two hundred seventy-six patients with a history of vasovagal syncope were prospectively followed for 2 years. Diagnosis of vasovagal syncope was based on clinical history and negative standard work-up. Inclusion in the study was independent from the result of the head-up tilt test, which was performed in all cases. Risk factors for syncope recurrence were evaluated by the Cox proportional hazards regression model and implemented in a risk score, which was validated with the log-rank test and an internal cross-validation.

RESULTS

The Cox-regression analysis identified the number of previous syncopal events, history of bronchial asthma, and female gender as predictors for syncope recurrence (all P < 0.05). In contrast, head-up tilt test response had no predictive value (P = 0.881). Developing a risk score, study patients were identified as having high (recurrence rate during 2 years of follow-up: 37.2%), intermediate (24.8%), and low (6.5%) risk for syncope recurrence (receiver operating characteristic [ROC] of score 0.83, P < 0.01; Log-rank test for event-free survival, P < 0.005).

CONCLUSIONS

In patients with vasovagal syncope, risk of recurrence can be stratified and is predictable based on a simple risk score.

Predicting the cause of syncope from clinical history in patients undergoing prolonged monitoring

BACKGROUND

Syncope may be the result of primary bradycardia or tachycardia, vasovagal syncope, or noncardiac syncope. Risk factors and outcome scores to predict prognosis in patients with syncope have been developed. Although these correlate with morbidity and mortality in patients with syncope, their relationship with the mechanism of syncope has not been investigated.

OBJECTIVE

The purpose of this study was to identify clinical predictors of primary bradycardia in a cohort of patients undergoing prolonged monitoring for unexplained syncope.

METHODS

One hundred nineteen patients underwent prolonged monitoring with an implantable or external loop recorder after assessment at a single-center, tertiary care arrhythmia service. Fifty-two patients with recurrent syncope during monitoring were classified according to the mechanism of syncope (International Study on Syncope of Uncertain Etiology [ISSUE] classification). Clinical predictors of primary arrhythmic syncope were identified.

RESULTS

Twenty patients were classified with primary arrhythmia and 32 patients were classified with nonarrhythmic syncope. Five clinical variables were associated with primary arrhythmia: left bundle branch block, structural heart disease, and syncope without prodrome increased the likelihood of primary arrhythmia; a normal baseline ECG and history of syncope in childhood decreased the likelihood of primary arrhythmia. After multiple logistic regression, risk factors for the diagnosis of primary arrhythmia included syncope without warning symptoms and structural heart disease. The presence of left bundle branch block correlated perfectly with primary arrhythmia, whereas a normal ECG reduced the likelihood of primary arrhythmia.

CONCLUSION

Clinical predictors of primary arrhythmia in patients with recurrent syncope include normal ECG and structural heart disease. Left bundle branch block is an important finding in patients with unexplained syncope.

Correlation between results of head-up tilt test and clinical features in patients with syncope or presyncope

BACKGROUND

Head-up tilt test (HUTT) is a well-established diagnostic tool in patients with suspected vasovagal syncope. Identification of factors that predict a positive HUTT result could simplify diagnostic steps. The aim of this study was to assess the correlation between clinical characteristics of patients with suspected neurocardiogenic syncope or presyncope and results of HUTT.

MATERIALS AND METHODS

The study group consisted of 90 patients (55 men, 35 women; mean age, 43.2 +/- 17 years) with a history of syncope or presyncope. Cardiological and neurologic test findings were normal in every patient. The patients were tilted to a 70 degrees position for 45 minutes. If the first phase produced a negative response, the patients received 400 mug of sublingual nitroglycerin for the second phase and continued to be tilted for an additional 15 minutes.

RESULTS

Sixty-four patients had a positive HUTT result, characterized by a vasodepressive response in 26 patients, mixed response in 24 patients, and cardioinhibitory response in 14 patients. In logistic regression analysis, the presence of prodromal symptoms was a predictor of a positive HUTT result (P = .002).

CONCLUSION

We showed that the prognostic performance of clinical features, including the time interval between the last episode and HUTT, the number of syncope or presyncope episodes, age, and sex, was not ideal. The presence of prodromal symptoms might be more likely to predict a positive response during HUTT.

Syncope in migraine: the population-based CAMERA study

OBJECTIVE

To examine the association between migraine and syncope-related autonomic nervous system (ANS) symptoms.

METHODS

A population-based study among migraineurs with and without aura (n = 323) and control subjects (n = 153) was conducted. A systematic questionnaire and cardiovascular measurements during rest, while standing, and after venipuncture addressed the prevalence of syncope, orthostatic intolerance, orthostatic hypotension (OH), and the postural tachycardia syndrome (POTS) in migraineurs and control subjects.

RESULTS

The lifetime prevalence of syncope in all participants was 41%, more often in women (45 vs 32%; p = 0.02). Compared with control subjects, migraineurs had a higher lifetime prevalence of syncope (46 vs 31%; p = 0.001), frequent syncope (five or more attacks) (13 vs 5%; p = 0.02), and orthostatic intolerance (32 vs 12%; p < 0.001). There was no association between ANS symptoms and the severity of migraine or migraine subtype. Cardiovascular measurements and the prevalence of POTS and OH did not differ significantly between migraineurs and control subjects.

CONCLUSION

This population-based study demonstrated an elevated prevalence of syncope and orthostatic intolerance in migraineurs without clear interictal signs of autonomic nervous system dysfunction.

The clinical impact of implantable loop recorders in patients with syncope

AIMS

Implantable loop recorders (ILR) provide an opportunity to record ECG data from a spontaneous syncopal event. We conducted a randomized study to investigate the impact of the Reveal Plus ILR on an unselected population of patients with recurrent syncope. Initial follow-up (at least 6 months) did not demonstrate a reduction in syncopal events or an improvement in quality of life. We report the planned extension of follow-up to 18 months.

METHODS AND RESULTS

All patients presenting acutely with recurrent unexplained syncope over a 16-month period, following a basic clinical work-up, were randomized to receive the ILR or conventional investigation and management. A total of 421 patients presented, 201 were eligible, median age 74, (IQ range 61-81) 54% female, with median syncopes 3 (IQ range 2-6). Median follow-up 17 months (IQ range 9-23). 42 (43%) of ILR patients and 8 (6%) of conventional patients received an ECG diagnosis (hazard ratio 6.53, 95% CI 3.73-11.4, P<0.001). Time to second syncope was significantly longer for ILR patients, although of borderline significance (P=0.04). A greater variety of diagnoses and treatments were seen in ILR patients. ILR patients had fewer post-randomization investigations and fewer days in hospital; however, cost savings were not statistically significant. There was improved quality of life in the ILR group (visual analogue scales, P=0.03) for general wellbeing. Overall mortality was 12% with no difference between the two groups.

CONCLUSION

Investigation by the ILR significantly increases the diagnostic rate and ECG directed treatments in a typical unselected syncopal population. Long-term follow-up has demonstrated a significant subsequent reduction in syncopal events with improved quality of life.

The diagnostic value of EEGs in patients with syncope

We retrospectively reviewed reports of all EEGs performed at the New Jersey Neuroscience Institute at JFK Hospital between January 1999 and December 2003. Of 9234 EEGs performed, 1094 were of patients with syncope. Among patients with syncope, 67.18% of the EEGs were normal and 28.15% showed diffuse and focal slowing. Only 1.46% of the EEGs showed epileptiform discharges (EDs). This is similar to the incidence of EDs in healthy adults. The presence of EDs did not change the management of these patients. Therefore, EEGs have very low yield and should not be routinely obtained in patients with syncope.

Does the use of a syncope diagnostic protocol improve the investigation and management of syncope?

OBJECTIVES

To assess the efficacy of a protocol designed to improve the diagnosis and management of syncope.

DESIGN

Prospective outcome analysis of all patients presenting with syncope for the 12 month period from 1 November 2000 to 31 October 2001, compared with a retrospective study of all patients presenting with syncope during the calendar year 1998. Use of the protocol commenced in September 2000.

SETTING

Eastbourne District General Hospital, serving a population of approximately 250 000; 25% are older than 65 years.

SUBJECTS

421 consecutive patients presenting with syncope, investigated prospectively in January 2000 and compared with 660 patients retrospectively analysed for the calendar year 1998.

RESULTS

In 1998, 71% of patients with syncope received a diagnostic classification. In January 2000 there was an appropriate diagnostic hypothesis for every patient. Ultimately a diagnosis was made for 78% of patients according to accepted criteria (p = 0.003). Use of tests with the highest diagnostic effectiveness, such as tilt tests, increased in 2001 and many tests were used more appropriately (such as echocardiography). However, non-diagnostic tests were still frequently used (such as chest radiography, electroencephalography, and carotid Doppler studies). Costs of investigation and hospital stay rose from pound 611 to pound 1384 (euro;874 to euro;1980) per patient (p < 0.001), with cost per diagnosis increasing from pound 870 (euro;1245) in 1998 to pound 1949 (euro;2790) (p < 0.001).

CONCLUSION

The syncope protocol improved diagnosis and the use of appropriate investigations. However, significant inappropriate investigation and hospital admission still occurred. The protocol allowed reliable triage of syncopal patients into high and low risk groups.

Hyperventilation-induced syncope: no need to panic

Accurately diagnosing and treating adult patients presenting with recurrent syncope can be extremely problematic. We present the case of a patient who presented with recurrent syncope. We propose that many cases currently classified as idiopathic may in fact be due to orthostatic hypotension secondary to hyperventilation, or simply hyperventilation-induced syncope. The presence of undiagnosed psychiatric disorders should be considered in these patients.

Transient loss of consciousness as reason for admission to primary health care emergency room

OBJECTIVE

To study the occurrence and main causes of transient loss of consciousness in primary health care.

DESIGN

A 4-month prospective survey.

SETTING

Primary health care emergency room of the City of Tampere, Finland.

SUBJECTS

Consecutive patients, aged over 15 years, admitted to the emergency room.

MAIN OUTCOME MEASURES

The overall prevalence of loss of consciousness divided into three subgroups: seizure, syncope and uncertain, and their distribution by gender and age. The prevalence of epilepsy, coronary heart disease and alcohol abuse among these diagnostic subgroups.

RESULTS

Of all emergency room visits, 1.2% were for loss of consciousness. Of these, 53% were diagnosed as seizures, 33% as syncope attacks and 14% as uncertain. In the seizure group, 75% of patients were men and 67% had a history of alcohol abuse. In the syncope group, 44% of patients had coronary heart disease and 68% were women.

CONCLUSION

Loss of consciousness is a fairly frequent problem for the primary health care emergency room. A history of alcohol abuse is commonly associated with seizures.

How do we diagnose syncope?

INTRODUCTION

The Eastbourne Syncope Assessment Study aims to increase diagnostic yield in unexplained syncope while reducing investigational costs. The initial study phase was a retrospective analysis of every presentation to the Eastbourne General Hospital (a busy nontertiary center in the United Kingdom serving a population of 250,000; 24% are older than 65 years) with syncope for the year 1998.

METHODS AND RESULTS

A total of 1,334 cases with syncopal codes were identified. Six hundred sixty patients (mean age 64 years) had actually suffered an episode of syncope. Forty percent had recurrent syncope, with a mean of 4.7 previous episodes. Twenty-nine percent of syncope cases remained undiagnosed. Forty-four percent were diagnosed as vasovagal, 12% neurologic, 6% due to an arrhythmia, 2% drug related, and 2% due to hemorrhage. Thirteen different types of investigation were undertaken, with an overall total of 3,264 investigations performed at a cost of Pound Sterling 104,285. Diagnosis was achieved by history and examination alone in 61% of cases. Excluding history and examination, the most cost-effective diagnostic tools were the 7-day patient-activated recorder (R test) and tilt testing (Pound Sterling 260 and Pound Sterling 401 per diagnosis, respectively). Investigations also were graded by their relative diagnostic power. Hospital admission alone accounted for 67% of the cost of investigating syncope.

CONCLUSION

In syncope, diagnostic rates can be improved and investigational costs reduced by concentrating on the most specific, sensitive, and cost-effective investigations and by minimizing hospital stay. Such a protocol currently is under investigation at our institution.