Continuous recording of dicrotic and pulse pressures during head-up tilting test: the vasodepressive profile. Preliminary data.

Background: The aim of this study was to assess whether a non-invasive automatic evaluation of the pulse wave characteristics could provide clinical clues when monitoring the hemodynamic adjustments to head-up tilting.

Methods: A continuous assessment of the peripheral pulse wave characteristics (systolic, diastolic, dicrotic and pulse pressures) in 8 control subjects with a negative response to head-up tilting (60 degrees for 45 min) compared to 13 syncopal patients with a vasodepressive one was performed.

Results: Controls exhibited, when up-tilted, an increase in blood pressure as well as in the dicrotic and pulse pressures and no changes in heart rate. On the contrary, syncopal patients showed a progressive increase in heart rate associated with a progressive decrease in dicrotic pressure and a trend towards lower values of pulse pressure, but no changes in systolic pressure. Thereafter and until the pre-syncopal symptoms supervened, the systolic, diastolic and dicrotic pressures progressively declined. A decrease in dicrotic pressure mainly characterized the early vasodepressive response while its increase identified the negative one.

Conclusions: Our data, even though preliminary, strongly suggest that automatic hemodynamic evaluation is to be used in the clinical setting as a monitor of the sudden changes in blood pressure induced by head-up tilting. Furthermore, the dicrotic and pulse pressures, even those measured during the early phases of the test, should be considered as non-invasive parameters characterizing the vasodepressive response to head-up tilting.