What role for diagnostic testing in syncope?

A retrospective review of approximately 170 children with new-onset syncope who visited a tertiary care center strongly suggests that diagnostic tests for this condition have a low yield and are very expensive. Investigators concluded, therefore, that such tests should be used principally to corroborate findings from the history and identify life-threatening diseases.

A diagnosis had been established in three quarters of the syncope patients, 4.5 to 18.7 years. Neurocardiogenic syncope accounted for 91% of all diagnoses. Overall, 663 tests had been obtained, at an overall cost of $180,128. The average cost for one patient was $1,055, and the cost of one diagnostic result was $6,928. Only 26 tests (3.9%) were diagnostic in 24 patients (14.2%), and tilt-testing accounted for almost half of diagnostic results. (Investigators considered test results diagnostic when an abnormal result correlated with the clinical diagnosis or a normal result was obtained during an episode of syncope.) The most common test was electrocardiography; 93% of patients had at least one ECG, but only one was diagnostic. Echocard-iography, which accounted for 14% of the total cost of testing, did not produce a single diagnostic result. Chest radiographs, cardiac catheterization, electrophysiology studies, and serum evaluations also were nondiagnostic (Steinberg LA et al: J Pediatr 2005;146:355).

Commentary Few tests for syncope bear fruit, but these authors aren't recommending that you abstain from all testing. Instead, proceed à la carte, selecting tests that are suggested by a careful history, physical exam, and screening ECG.