title: Use of a computer in analysis of heart rate and blood pressure response to the Valsalva maneuver.
abstract: The relationship between systolic blood pressure (SBP) and R-R interval (RR) in phase II of the Valsalva maneuver was analyzed with the use of a nonlinear relation. The nonlinear relation introduced here includes time derivatives of SBP and RR, and is a natural extension from the linear one which defines the linear baroreflex sensitivity index (BRSI). The model equations of SBP and RR derived from the nonlinear relation predicted well the observed changes of SBP and RR in 11 normotensive subjects and 16 hypertensive patients. Two of the parameters of the relation were related to the activity of the compensatory mechanism, and discriminated well the hypertensives from the normotensives. For this analysis an interactive system of regression analysis has been developed to reduce the difficulties in the case of nonlinear regression curve fitting. The regression curves can be monitored on a graphic terminal during every regression step. The values of nonlinear parameters can be obtained easily and systematically with use of the system.
mesh_terms: D000328:Adult; D000368:Aged; D001699:Biometry; D001794:Blood Pressure; D003201:Computers; D005260:Female; D006339:Heart Rate; D006801:Humans; D006973:Hypertension / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D014636:Valsalva Maneuver