DOES CARDIAC DENERVATION AFFECT THE SHORT-TERM BLOOD-PRESSURE VARIABILITY IN HUMANS

Objective: To explore the repercussion of cardiac denervation on the s hort-term blood pressure variability in humans, in order to assess the extent to which the variability of blood pressure is linked to the va riability of heart rate.Methods: Beat-to-beat blood pressure and RR in terval time were recorded in 16 heart-transplanted patients and were c ompared with those of 10 healthy control subjects in the resting supin e, sitting and standing positions. Blood pressure and RR interval vari abilities were assessed by spectral analysis. Results: The total blood pressure power and the supine and sitting very low-frequency, low-fre quency and high-frequency blood pressure variability were similar in t he heart-transplanted patients and in the controls, despite a marked r eduction in the RR interval variability in the heart-transplanted pati ents. However, the heart-transplanted patients had lower standing low- frequency blood pressure variability than the control subjects. Moreov er, very low-frequency and low-frequency RR interval variabilities rea ppeared in the long-term heart-transplanted patients but not in the sh ort-term heart-transplanted patients (range of time after transplantat ion 53-124 and 3-25 months, respectively). Conclusions: Short-term RR interval fluctuations are not mandatory for the maintenance of normal blood pressure variability in the supine and sitting positions, but ma y contribute to the increase in the low-frequency blood pressure varia bility which occurs normally in the standing position. Moreover, the l ong-term heart-transplanted patients had increased RR interval variabi lity, which may have been caused by the reappearance of limited autono mic cardiac modulation. However, this increased RR interval variabilit y did not affect the corresponding blood pressure variability.