Incidence and Prognosis of Syncope

National Heart, Lung, and Blood Institute Framingham Heart Study, Framingham, Mass 01702-5827, USA.
New England Journal of Medicine (Impact Factor: 55.87). 10/2002; 347(12):878-85. DOI: 10.1056/NEJMoa012407
Source: PubMed


Little is known about the epidemiology and prognosis of syncope in the general population.
We evaluated the incidence, specific causes, and prognosis of syncope among women and men participating in the Framingham Heart Study from 1971 to 1998.
Of 7814 study participants followed for an average of 17 years, 822 reported syncope. The incidence of a first report of syncope was 6.2 per 1000 person-years. The most frequently identified causes were vasovagal (21.2 percent), cardiac (9.5 percent), and orthostatic (9.4 percent); for 36.6 percent the cause was unknown. The multivariable-adjusted hazard ratios among participants with syncope from any cause, as compared with those who did not have syncope, were 1.31 (95 percent confidence interval, 1.14 to 1.51) for death from any cause, 1.27 (95 percent confidence interval, 0.99 to 1.64) for myocardial infarction or death from coronary heart disease, and 1.06 (95 percent confidence interval, 0.77 to 1.45) for fatal or nonfatal stroke. The corresponding hazard ratios among participants with cardiac syncope were 2.01 (95 percent confidence interval, 1.48 to 2.73), 2.66 (95 percent confidence interval, 1.69 to 4.19), and 2.01 (95 percent confidence interval, 1.06 to 3.80). Participants with syncope of unknown cause and those with neurologic syncope had increased risks of death from any cause, with multivariable-adjusted hazard ratios of 1.32 (95 percent confidence interval, 1.09 to 1.60) and 1.54 (95 percent confidence interval, 1.12 to 2.12), respectively. There was no increased risk of cardiovascular morbidity or mortality associated with vasovagal (including orthostatic and medication-related) syncope.
Persons with cardiac syncope are at increased risk for death from any cause and cardiovascular events, and persons with syncope of unknown cause are at increased risk for death from any cause. Vasovagal syncope appears to have a benign prognosis.

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Available from: Leway Chen, Oct 04, 2015
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    • "The probability of death in both patient groups was based on the Portuguese Population age–specific mortality rate [18]. Following Soteriades et al. [11], this rate was adjusted by a factor of 1.32 to take into consideration the adjusted hazard ratio for the risk of death from any cause in patients with unexplained syncope. We applied a rate of 0.6 syncopes per year among undiagnosed patients in both arms (the value was adjusted to the 3-month cycle length used), based on follow-up data from Farwell [19]. "
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    ABSTRACT: Background To estimate the short- and long-term financial impact of early referral for implantable loop recorder diagnostic (ILR) versus conventional diagnostic pathway (CDP) in the management of unexplained syncope (US) in the Portuguese National Health Service (PNHS). Methods A Markov model was developed to estimate the expected number of hospital admissions due to US and its respective financial impact in patients implanted with ILR versus CDP. The average cost of a syncope episode admission was estimated based on Portuguese cost data and landmark papers. The financial impact of ILR adoption was estimated for a total of 197 patients with US, based on the number of syncope admissions per year in the PNHS. Sensitivity analysis was performed to take into account the effect of uncertainty in the input parameters (hazard ratio of death; number of syncope events per year; probabilities and unit costs of each diagnostic test; probability of trauma and yield of diagnosis) over three-year and lifetime horizons. Results The average cost of a syncope event was estimated to be between 1,760€ and 2,800€. Over a lifetime horizon, the total discounted costs of hospital admissions and syncope diagnosis for the entire cohort were 23% lower amongst patients in the ILR group compared with the CDP group (1,204,621€ for ILR, versus 1,571,332€ for CDP). Conclusion The utilization of ILR leads to an earlier diagnosis and lower number of syncope hospital admissions and investigations, thus allowing significant cost offsets in the Portuguese setting. The result is robust to changes in the input parameter values, and cost savings become more pronounced over time.
    BMC Cardiovascular Disorders 05/2014; 14(1):63. DOI:10.1186/1471-2261-14-63 · 1.88 Impact Factor
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    • "Among patients less than 65 years of age, cardiac syncope comprises little more than one-fifth of causes of syncope, whereas in patients above 65 years it is the cause of syncope in 42% of cases [2,3]. Importantly, patients with cardiac syncope are at increased risk of cardiovascular events and mortality [4]. "
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    ABSTRACT: We aimed to develop and test a literature-based model for symptoms that associate with cardiac causes of syncope. Seven studies (the derivation sample) reporting ≥2 predictors of cardiac syncope were identified (4 Italian, 1 Swiss, 1 Canadian, and 1 from the United States). From these, 10 criteria were identified as diagnostic predictors. The conditional probability of each predictor was calculated by summation of the reported frequencies. A model of conditional probabilities and a priori probabilities of cardiac syncope was constructed. The model was tested in four datasets of patients with syncope (the test sample) from Calgary (n=670; 21% had cardiac syncope), Amsterdam (n=503; 9%), Milan (n=689; 5%) and Rochester (3877; 11%). In the derivation sample ten variables were significantly associated with cardiac syncope: age, gender, structural heart disease, low number of spells, brief or absent prodrome, supine syncope, effort syncope, and absence of nausea, diaphoresis and blurred vision. Fitting the test datasets to the full model gave C-statistics of 0.87 (Calgary), 0.84 (Amsterdam), 0.72 (Milan) and 0.71 (Rochester). Model sensitivity and specificity were 92% and 68% for Calgary, 86% and 67% for Amsterdam, 76% and 59% for Milan, and 73% and 52% for Rochester. A model with 5 variables (age, gender, structural heart disease, low number of spells, and lack of prodromal symptoms) was as accurate as the total set. A simple literature-based Bayesian model of historical criteria can distinguish patients with cardiac syncope from other patients with syncope with moderate accuracy.
    PLoS ONE 09/2013; 8(9):e75255. DOI:10.1371/journal.pone.0075255 · 3.23 Impact Factor
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    • "Head turning has been shown to increase cardiovagal baroreflex sensitivity, which could lower the threshold for carotid sinus sensitivity [22]. The high prevalence of CSH is thought to underlie the increasing prevalence of syncope with advancing age [23]. "
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    ABSTRACT: Carotid sinus hypersensitivity has a high prevalence in the elderly and is a possible cause of falls. In carotid sinus hypersensitivity, external triggers cause sudden reductions in blood pressure, leading to dizziness or syncope, resulting in falls. Turning of the head is considered an important example of such an external trigger in everyday life, wherein rotation of the neck is thought to manipulate the hypersensitive carotid sinus. However, direct evidence for this is lacking. The aim of this study was to investigate the effects of head turning in elderly with carotid sinus hypersensitivity. We performed a prospective, observational study in 105 elderly patients who visited a geriatric falls clinic in a university teaching hospital and in 25 community dwelling healthy elderly subjects. Continuous measurements of blood pressure and heart rate (Finapres) were performed before, during, and after head turning. Head turning-induced hypotension was defined as a drop in systolic blood pressure of at least 20 mmHg during head turning. Carotid sinus hypersensitivity was examined with carotid sinus massage. We also tested for two other common geriatric hypotensive syndromes, orthostatic hypotension and post prandial hypotension, using active standing and a meal test. All three hypotensive syndromes were defined using consensus definitions. Head turning resulted in hypotension in 39% of patients (mean systolic blood pressure drop 36 mm Hg) and in 44% of the healthy elderly, irrespective of the direction of the head movement. Carotid sinus hypersensitivity was associated with head-turning induced hypotension (OR= 3.5, 95% CI= 1.48 to 8.35). We conclude that head turning is indeed an important cause of sudden drops in blood pressure in elderly with carotid sinus hypersensitivity.
    PLoS ONE 08/2013; 8(8):e72837. DOI:10.1371/journal.pone.0072837 · 3.23 Impact Factor
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