Baroreflex sensitivity for falling pressures was significantly correlated with cardiac vagal tone (R = 0.81, P = 0.002), indicating vagal tone is generated by both dependent and independent mechanisms.
Observational (n=12)
Does baroreflex sensitivity correlate with cardiac vagal tone in healthy young adults?
Cardiac vagal tone is generated by both baroreflex-dependent and -independent mechanisms, with the baroreflex-dependent mechanism being dominant.
Effect estimate: R = 0.81
p-value: p=0.002
The extent of dependence of cardiac vagal tone on arterial baroreceptor input has been studied in 12 healthy, young adult subjects. Cardiac vagal tone was defined as the chang in R-R interval after complete cholinergic blockade by atropine. Baroreflex sensitivity was determined with the "Oxford-method": R-R interval was regressed against systolic pressure. The interindividual correlation between cardiac vagal tone and baroreflex sensitivity for falling pressures was found to be significant, but not close (R = 0.81, P = 0.002). In each subject, the baroreflex regression line for falling pressures was extrapolated to the post-atropine R-R interval level; 50 mmHg was considered as minimum and 80 mmHg as maximum threshold level for the integrated baroreflex. From the relation between the individual regression lines and the minimum and maximum threshold levels, it was concluded that cardiac vagal tone could be generated by both baroreflex-dependent and -independent mechanisms, the ratio of which varies in different individuals, with the baroreflex-dependent mechanism being the dominant factor.
Kollai et al. (Sat,) conducted a observational in Healthy (n=12). Baroreflex sensitivity was evaluated on Correlation between cardiac vagal tone and baroreflex sensitivity for falling pressures (R = 0.81, p=0.002). Baroreflex sensitivity for falling pressures was significantly correlated with cardiac vagal tone (R = 0.81, P = 0.002), indicating vagal tone is generated by both dependent and independent mechanisms.