Cardiovagal Reflex Blood Pressure Set Point Determination by Time Domain Analysis

Abstract

The baroreflex is not only an important marker of cardiac risk, but also can serve as a monitor of improvements in baroreflex sensitivity and consequences of drug treatments, physical training, etc. Sensitivity is not the only parameter of baroreflex function, but another very important is the set point. This allows to know the value of blood pressure that baroreflex tries to stabilize. A method to obtain the Blood Pressure Set Point corresponding to vagal baroreflex curve, based on the analysis of blood pressure and heart pulse interval variability is presented. The Eurobavar, which is a heterogeneous dataset, extracted from subjects with different reflex response is used to test the method. Systolic Blood Pressure (SBP) and interval time between beats (RR) series are constructed using records from that Dataset. From both series baroreflex sequences are extracted using traditional Sequence Method. Instead of computing the average of the slopes obtained from all arterial pressure points, we segment the pressure space in non-overlapping windows of 10 mm of Hg wide averaging the gain values corresponding to pressure values within each window (data binning). The Blood Pressure corresponding to the maximum of histograms curves, constructed from SBP of the baroreflex sequences, is used to contrast the result obtained with other method. Results were 119 ± 17,7mmHg for method 1 and 118 ± 21,9 mmHg for method 2. In conclusion, with only rearranging the data, an important parameter, such as Set Point of the baroreflex, can be achieved.