Incidence and Prognosis of Syncope

Among 7814 participants in the Framingham Heart Study who were followed for an average of 17 years, 822 had at least one episode of syncope, and the incidence of a first report of syncope was 6.2 per 1000 person-years. Vasovagal and cardiac causes were most common; the cause was not identified in over a third of cases. Mortality was increased among all participants with syncope, among those with syncope of unknown cause, and particularly among those with cardiac syncope, as compared with participants who did not have syncope. Vasovagal syncope had a benign prognosis. Mortality was increased with syncope of unknown cause and with cardiac syncope. Vasovagal syncope had a benign prognosis. Syncope, defined as a sudden loss of consciousness associated with the inability to maintain postural tone, followed by spontaneous recovery, is relatively common. However, the epidemiology and prognosis of syncope in the community have not been well described. Data are limited on the cumulative incidence 1 , 2 and lifetime prevalence 3 – 7 of syncope. Although syncope has many possible causes, several studies have used three categories of cause — cardiac, noncardiac, and unknown — to examine the prognosis of syncope prospectively. 8 Previous studies of syncope were conducted in emergency departments, 9 – 12 in general hospitals, 13 – 17 and among highly selected subgroups of patients . . .