INCIDENCE
AND PROGNOSIS OF SYNCOPE.
Soteriades ES, Evans et al. N Engl J Med 2002 Sep 19;347(12):878-85
BACKGROUND: Little is known about the epidemiology and
prognosis of syncope in the general population.
METHODS: We evaluated the incidence, specific causes, and
prognosis of syncope among women and men participating in the Framingham Heart
Study from 1971 to 1998.
RESULTS: 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.
CONCLUSIONS: 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.