[Effect of time elapsed from spontaneous syncope on the diagnostic performance of the head-up tilt table test]

The propensity for spontaneous and tilt-induced neurocardiogenic syncope may exhibit temporal variations. Therefore the diagnostic performance of the head-up tilt test could be improved if it were performed soon after the occurrence of spontaneous syncope. The objective of this study was to assess whether the time interval between the last syncopal episode and tilt table testing influenced the outcome of the test.

Three hundred and fifteen patients undergoing diagnostic tilt table testing potentiated with nitroglycerin for suspected neurocardiogenic syncope were included in the study. The time between the last spontaneous syncope and the tilt table test was recorded and its relationship with the results of the test was analyzed.

The tilt table test was positive in 211 patients (67.0%). The time from syncope to test was similar for patients with positive and negative tilt table test results: 28 (1-500) vs 32 (2-700) days (NS). No significant relation was observed between the results of the test and the occurrence of spontaneous syncope during the week, the month or the three months previous to the procedure. However, in men and in patients older than 50 years a higher rate of positive tests was observed if the tilt test was performed within the first month after the last spontaneous syncope.

The time from the last previous spontaneous syncope to the head-up tilt test does not have a significant impact on test outcome in the overall population with suspected neurocardiogenic syncope. However, the rate of positivity might decrease in men and patients older than 50 years if the test is performed later than one month after the spontaneous syncopal episode.