Predicting the Outcomes of Inpatient Cardiac Evaluation for Syncope Using Validated Risk Scores

Background: Validated syncope risk scores were aimed to predict a cardiac etiology and are mainly used in the decision of hospital admission. Whether these scores could also predict the outcomes of inpatient cardiac evaluation is unknown and was the subject of our study. Methods: This was an observational study including consecutive patients admitted for syncope evaluation. All patients completed prolonged electrocardiogram monitoring and an echocardiography before discharge. The area under the receiver-operating characteristic curve (AUC) was used to evaluate the ability of validated risk scores to predict positive inpatient findings. Subsequently, a multivariate regression was performed to identify independent predictors for positive cardiac evaluation, which were then incorporated into the best predictive risk scores. Results: Three hundred ninety-seven patients were included, 56 (14%) with a positive inpatient cardiac evaluation. The Osservatorio Epidemiologico sulla Sincope Lazio and Canadian Syncope Risk Score achieved the largest AUC (0.701, 95% confidence interval [CI] 0.63-0.77 and 0.694, 95% CI 0.62-0.77, respectively). Yet, all scores provided relatively high sensitivity with low specificity. Multivariate regression revealed age ≥75 (adjusted odds ratio 3.50, 95% CI 1.5-7.9) and abnormal cardiac auscultation (adjusted odds ratio 4.79, 95% CI 2.5-9.1) to be independent predictors. Incorporating these factors led to a significantly higher prediction ability of the Osservatorio Epidemiologico sulla Sincope Lazio (AUC of 0.787, P < .01) and Canadian Syncope Risk Score (AUC 0.778, P < .01) modified scores. Conclusions: Current syncope risk scores provide limited prediction ability for the outcomes of inpatient cardiac syncope work-up. One should specifically consider age > 75 years and either cardiac murmur or irregular heart rate on examination very significant in implying a cardiac etiology for syncope. Although these factors may be obvious, current risk scores can be interpreted in such a fashion that ignores the importance of findings extracted from a good history and physical examination.