Blood pressure — Heart rate syncronization coefficient as a complementary indicator of baroreflex mechanism efficiency

We aimed at studying the efficiency of blood pressure - heart rate feedback regulation, in particular the arterial baroreflex mechanism. We analyzed 150 short-term beat-to-beat recordings of blood pressure and pulse intervals and calculated their level of synchronization. We determined the synchronization coefficient as a fraction of the record fragments where the standard deviation of the Hilbert phase difference of blood pressure and pulse intervals was below a given threshold. Our results indicate that the synchronization coefficient is significantly lower in records with high blood pressure variability while does not correlate significantly with the arterial baroreflex sensitivity. Accordingly, the synchronization coefficient may be used as a complementary indicator of blood pressure feedback regulation, since it reflects how often the feedback mechanism is activated. We suggest that the product of the synchronization coefficient and the baroreflex sensitivity could be used as a potential measure of the total efficiency of baroreflex mechanism and thus of blood pressure feedback control.