Session P7A.5

Are the Augmentation Index and the Delay Time between Systolic and Diastolic Peaks Useful Markers to Assess Vasovagal Syncope?

JC Perfetto*, AGR Aurora Ruiz

Biomedical Engineering Institute
Buenos Aires, Argentina

Recently, several authors are proposing the use of geometrical indexes measured from non invasive, central or peripheral pressure waveforms, to discriminate between patients suffering vasovagal syncopes (V.V.S) from others. These indices are been usually associated with arterial stiffness and ageing. The passive head up test (H.U.T) is the accepted tool to do this task. The possibility of avoiding this maneuver looks very attractive. ECG and non invasive arterial pressure (N.A.P.) were sampled at 1200 Hz with 12-bit resolution and stored digitally for off-line analysis. Analog output from a radial tonometry monitor was used to acquire the arterial pressure. These parameters were recorded during supine rest and during a 45min 70° HUT test in 16 patients (22±6 years) with a history of unexplained recurrent syncope and 14 controls (21±4). Delay time between systolic and diastolic peaks, and augmentation index IA were computed in supine, and also in tilt position. IA was determined as the ratio between the amplitude of the diastolic peak and the pulse pressure. All the processing was done with a custom PC program The results are: DT (316, 46 ± 26, 45) for the syncope group vs. (313, 80 ± 22, 80) for the control group in supine position and (255, 7 ± 16, 28) vs. (241, 72 ± 12, 74) for tilt. IA (61, 9 ± 5, 9) for the syncope group vs. (60, 36 ± 11, 56) for the control group in supine position, and (58, 9 ± 5, 29) vs. (58, 5 ± 5, 1) for tilt. No significant differences were found between groups. We cannot confirm the hypotheses proposed by other authors.

(Abstract Control Number: 187)