Tilt testing: is it necessary in all patients with suspected vaso-vagal syncope?

Head-up tilt testing (HUTT) is a well-established diagnostic tool in patients with suspected vaso-vagal syncope (VVS). However, it is time-consuming and requires special equipment. Thus, identification of simple parameters which could predict the outcome of HUTT could simplify diagnostic steps by obviating the need for HUTT.

To assess which symptoms associated with spontaneous syncope or other details from medical history can predict HUTT results.

The study group consisted of 202 unselected patients (69 males, mean age 43 +/- 20 years) who were admitted to our syncope unit for HUTT due to suspected VVS. They filled in a detailed questionnaire including 34 standard questions concerning medical history as well as circumstances and symptoms associated with syncopal episodes. Patients were tilted to 70 degrees for 45 minutes or the test was stopped earlier if syncope occurred. A stepwise multiple logistic regression was performed in order to assess which parameters independently predicted the results of HUTT. A point-score was developed by assigning +/-1, +/-2, or +/-3 points to each of the factors based on the relative magnitude of the estimated regression coefficient. The points were then summed and a diagnostic threshold chosen using plots of sensitivity and specificity curves.

Syncope was induced by HUTT in 67 (33%) patients. In the whole study group, a point-score identified patients with positive HUTT with a sensitivity of 87.9%, and specificity of 36.3%. When the analysis was confined to the subgroup with >4 syncopal episodes in the past, the sensitivity of a point-score was 94.4%, and specificity--60%, and in the subgroup with >2 syncopal episodes occurring within 1 month preceding HUTT, sensitivity values reached 88.2% at the specificity level of 90.9%.

In patients with frequent syncopal episodes, especially clustered shortly before performing HUTT, in whom symptoms are very suggestive of VVS, a simple point-score system based on medical history accurately predicts HUTT results. Thus, HUTT may not be necessary for establishing diagnosis in this group of patients.