[Syncope in a general population: etiologic diagnosis and follow-up. Results of a prospective study].

Objective: Syncope is a common clinical problem in a general population. A prospective study was performed, in our hospital, to evaluate the incidence of the disease and to standardize the diagnostic and clinical management.

Methods: 194 patients aged 10-92 years were recruited during one year. The diagnostic produce followed the three standard stages: First stage clinical evaluation (a complete history, physical and neurological examination, a base-line laboratory evaluation, a 12-lead electrocardiogram, carotid sinus stimulation); Second stage non invasive investigation (echocardiogram, 24-hour electrocardiographic monitoring, electroencephalography, Doppler echocardiography of epiaortic vessels, head-up tilt test, head CT scan); third stage invasive investigation (electrophysiologic study).

Results: Diagnosis was, sometimes, difficult because of the sporadic and transitory nature of the syncope. The etiological diagnosis were the following: cardiovascular causes 68.55% (cardiac 31.95%, reflex syncope 36.59%). Non-cardiovascular causes 10.82% (metabolic 5.15%, neurologic 3.5%, different 2.06%). Unknown cause 20.61%. Diagnosis was determined at the following stages: ist stage 63.40% (complete history and physical examination alone 4072%), 2nd stage 14.43%, 3rd stage 1.54%. The mean follow-up period was 21.71 +/- 6.22 months. Over this period 17 (8.76) patients died; all aged (> 65 years) end in this aged the incidence is 18.08%. If we look at patients with correct diagnosis of syncope (183 patients) the mortality rate is 8.19% (if we consider those aged > 65 the rate is 17.44%). The mortality rate of cardiac syncope of unknown (28.88% for aged > 65 years). 2 deaths among syncope of unknown cause. 17.48% had 1 or more episodes of recurrent syncope during this follow-up period with little prevalence for patients with syncope of unknown origin. Other major cardiovascular events was 18.03% in all patients with little prevalence for cardiac cause of syncope.

Conclusions: 1) Frequently an accurate history, a physical examination and a standard ECG are enough to formulate a correct diagnosis. 2) Head-up tilt test must be considered in patients with a unknown diagnosis, before starting invasive investigation. 3) Prognosis is dependent on the specific cause. Since cardiac syncope has a serious prognosis, when it is not treated correctly, it can even lead to sudden death.