Diagnostic criteria for vasovagal syncope based on a quantitative history

Our goal was to develop historical criteria for the diagnosis of vasovagal syncope.

We administered a 118-item historical questionnaire to 418 patients with syncope and no apparent structural heart disease. The prevalence of each item was compared between patients with positive tilt tests and those with syncope of other, known causes. The contributions of symptoms to diagnoses were estimated with logistic regression, point scores were developed, and the scores were tested using receiver operator characteristic analysis. The accuracy of the decision rule was assessed with bootstrapping. Data sets were complete for all subjects. The causes of syncope were known in 323 patients and included tilt-positive vasovagal syncope (235 patients) and other diagnoses such as complete heart block and supraventricular tachycardias (88 patients). The point score correctly classified 90% of patients, diagnosing vasovagal syncope with 89% sensitivity and 91% specificity. The decision rule suggested that 68% of an additional 95 patients with syncope of unknown cause and a negative tilt test have vasovagal syncope.

A simple point score of historical features distinguishes vasovagal syncope from syncope of other causes with very high sensitivity and specificity.