Do symptoms predict cardiac arrhythmias and mortality in patients with syncope?

Background: Patients with syncope frequently present with multitude of othe r symptoms but their significance in predicting morbidity or mortality has not been previously studied. Objective: To determine if certain symptoms can be used to identify syncope patients at risk for cardiac arrhythmias, mortality, or recurrence of sync ope. Patients and Methods: From August 1987 to February 1991, we prospectively e valuated patients with syncope from outpatient, inpatient, and emergency de partment services of a university medical center. These patients were inter viewed, charts were reviewed, and detailed information on 19 symptoms and c omorbidities was obtained. A cause of syncope was assigned using standardiz ed diagnostic criteria. All patients were followed up at 3-month intervals for at least 1 year for recurrence of syncope and mortality. Patients in wh om the cause of syncope was determined by medical history and physical exam ination alone were not included in our analysis. Results: History and physical examination led to the cause of syncope in 22 2 of 497 patients enrolled. In the remaining 275 patients, the absence of n ausea and vomiting before syncope (odds ratio, 7.1) and electrocardiographi c abnormalities (odds ratio, 23.5) were predictors of arrhythmic syncope. U nderlying cardiac disease was the only predictor of 1-year mortality. No sy mptom remained as independent predictor for 1-year mortality or syncope rec urrence. Conclusions: Symptoms, although important in assigning many noncardiac caus es, are not useful in risk-stratifying patients whose cause of syncope cann ot be identified by other history and physical examination. Triage decision s and management plans should be based on preexisting cardiac disease or el ectrocardiographic abnormalities, which are important predictors of arrhyth mic syncope and mortality.